[1] The Value of Physiological Knowledge. “If any one doubts the importance of an acquaintance with the fundamental principles of physiology as a means to complete living, let him look around and see how many men and women he can find in middle life, or later, who are thoroughly well. Occasionally only do we meet with an example of vigorous health continued to old age; hourly do we meet with examples of acute disorder, chronic ailment, general debility, premature decrepitude. Scarcely is there one to whom you put the question, who has not, in the course of his life, brought upon himself illness from which a little knowledge would have saved him. Here is a case of heart disease consequent on a rheumatic fever that followed a reckless exposure. There is a case of eyes spoiled for life by overstudy.
“Not to dwell on the natural pain, the gloom, and the waste of time and money thus entailed, only consider how greatly ill health hinders the discharge of all duties,—makes business often impossible, and always more difficult; produces irritability fatal to the right management of children, puts the functions of citizenship out of the question, and makes amusement a bore. Is it not clear that the physical sins—partly our ancestors’ and partly our own—which produce this ill health deduct more from complete living than anything else, and to a great extent make life a failure and a burden, instead of a benefaction and a pleasure?”—Herbert Spencer.

[2] The word protoplasm must not be misunderstood to mean a substance of a definite chemical nature, or of an invariable morphological structure; it is applied to any part of a cell which shows the properties of life, and is therefore only a convenient abbreviation for the phrase “mass of living matter.”

[3] “Did we possess some optic aid which should overcome the grossness of our vision, so that we might watch the dance of atoms in the double process of making and unmaking in the living body, we should see the commonplace, lifeless things which are brought by the blood, and which we call food, caught up into and made part of the molecular whorls of the living muscle, linked together for a while in the intricate figures of the dance of life, giving and taking energy as they dance, and then we should see how, loosing hands, they slipped back into the blood as dead, inert, used-up matter.”—Michael Foster, Professor of Physiology in the University of Cambridge, England.

[4] “Our material frame is composed of innumerable atoms, and each separate and individual atom has its birth, life, and death, and then its removal from the ‘place of the living.’ Thus there is going on a continuous process of decay and death among the individual atoms which make up each tissue. Each tissue preserves its vitality for a limited space only, is then separated from the tissue of which it has formed a part, and is resolved into its inorganic elements, to be in due course eliminated from the body by the organs of excretion.”—Maclaren’s Physical Education.

[5] The periosteum is often of great practical importance to the surgeon. Instances are on record where bones have been removed, leaving the periosteum, within which the entire bone has grown again. The importance of this remarkable tissue is still farther illustrated by experiments upon the transplantation of this membrane in the different tissues of living animals, which has been followed by the formation of bone in these situations. Some years ago a famous surgeon in New York removed the whole lower jawbone from a young woman, leaving the periosteum and even retaining in position the teeth by a special apparatus. The entire jawbone grew again, and the teeth resumed their original places as it grew.

[6] The mechanism of this remarkable effect is clearly shown by an experiment which the late Dr. Oliver Wendell Holmes used to take delight in performing in his anatomical lectures at the Harvard Medical College. He had a strong iron bar made into a ring of some eight inches in diameter, with a space left between the ends just large enough to be filled by an English walnut. The ring was then dropped to the floor so as to strike on the convexity just opposite to the walnut, which invariably was broken to pieces.

[7] For the treatment of accidents and emergencies which may occur with reference to the bones, see Chapter XIII.

[8] “Besides the danger connected with the use of alcoholic drinks which is common to them with other narcotic poisons, alcohol retards the growth of young cells and prevents their proper development. Now, the bodies of all animals are made up largely of cells, ... and the cells being the living part of the animal, it is especially important that they should not be injured or badly nourished while they are growing. So that alcohol in all its forms is particularly injurious to young persons, as it retards their growth, and stunts both body and mind. This is the theory of Dr. Lionel S. Beale, a celebrated microscopist and thinker, and is quite generally accepted.”—Dr. Roger S. Tracy, of the New York Board of Health.

[9] “In its action on the system nicotine is one of the most powerful poisons known. A drop of it in a concentrated form was found sufficient to kill a dog, and small birds perished at the approach of a tube containing it.”—Wood’s Materia Medica.
“Tobacco appears to chiefly affect the heart and brain, and I have therefore placed it among cerebral and cardiac poisons.”—Taylor’s Treatise on Poisons.

[10] “Certain events occur in the brain; these give rise to other events, to changes which travel along certain bundles of fibers called nerves, and so reach certain muscles. Arrived at the muscles, these changes in the nerves, which physiologists call nervous impulses, induce changes in the muscles, by virtue of which these shorten contract, bring their ends together, and so, working upon bony levers, bend the arm or hand, or lift the weight.”—Professor Michael Foster.

[11] The synovial membranes are almost identical in structure with serous membranes (page 176), but the secretion is thicker and more like the white of egg.

[12] “Smoking among students or men training for contests is a mistake. It not only affects the wind, but relaxes the nerves in a way to make them less vigorous for the coming contest. It shows its results at once, and when the athlete is trying to do his best to win he will do well to avoid it.” Joseph Hamblen Sears, Harvard Coach, and Ex-Captain of the Harvard Football Team, Article in In Sickness and in Health.

[13] “There is no profession, there is no calling or occupation in which men can be engaged, there is no position in life, no state in which a man can be placed, in which a fairly developed frame will not be valuable to him; there are many of these, even the most purely and highly intellectual, in which it is essential to success—essential simply as a means, material, but none the less imperative, to enable the mind to do its work. Year by year, almost day by day, we see men (and women) falter and fail in the midst of their labors; ... and all for want of a little bodily stamina—a little bodily power and bodily capacity for the endurance of fatigue, or protracted unrest, or anxiety, or grief.”—Maclaren’s Physical Education.

[14] “One half the struggle of physical training has been won when a boy can be induced to take a genuine interest in his bodily condition,—to want to remedy its defects, and to pride himself on the purity of his skin, the firmness of his muscles, and the uprightness of his figure. Whether the young man chooses afterwards to use the gymnasium, to run, to row, to play ball, or to saw wood, for the purpose of improving his physical condition, matters little, provided he accomplishes that object.”—Dr. D. A. Sargent, Director of the Hemenway Gymnasium at Harvard University.

[15] “It is health rather than strength that is the great requirement of modern men at modern occupations; it is not the power to travel great distances, carry great burdens, lift great weights, or overcome great material obstructions; it is simply that condition of body, and that amount of vital capacity, which shall enable each man in his place to pursue his calling, and work on in his working life, with the greatest amount of comfort to himself and usefulness to his fellowmen.”—Maclaren’s Physical Education.

[16] To this classification may be added what are called albuminoids, a group of bodies resembling proteids, but having in some respects a different nutritive value. Gelatine, such as is found in soups or table gelatine is a familiar example of the albuminoids. They are not found to any important extent in our raw foods, and do not therefore usually appear in the analyses of the composition of foods. The albuminoids closely resemble the proteids, but cannot be used like them to build up protoplasm.

[17] The amount of water in various tissues of the body is given by the following table in parts of 1000:

[18] The work of some kinds of moulds may be apparent to the eye, as in the growths that form on old leather and stale bread and cheese. That of others goes on unseen, as when acids are formed in stewed fruits. Concerning the work of the different kinds of moulds. Troussart says: “Mucor mucedo devours our preserves; Ascophora mucedo turns our bread mouldy; Molinia is nourished at the expense of our fruits; Mucor herbarium destroys the herbarium of the botanist; and Choetonium chartatum develops itself on paper, on the insides of books and on their bindings, when they come in contact with a damp wall.”—Troussart’s Microbes, Ferments, and Moulds.

[19] “The physiological wear of the organism is constantly being repaired by the blood; but in order to keep the great nutritive fluid from becoming impoverished, the matters which it is constantly losing must be supplied from some source out of the body, and this necessitates the ingestion of articles which are known as food.”—Flint’s Text-book of Human Physiology.

[20] Glands. Glands are organs of various shapes and sizes, whose special work it is to separate materials from the blood for further use in the body, the products being known as secretion and excretion. The means by which secretion and excretion are effected are, however, identical. The essential parts of a gland consist of a basement membrane, on one side of which are found actively growing cells, on the other is the blood current, flowing in exceedingly thin-walled vessels known as the capillaries. The cells are able to select from the blood whatever material they require and which they elaborate into the particular secretion. In Fig. 47 is illustrated, diagrammatically, the structure of a few typical secreting glands. The continuous line represents the basement membrane. The dotted line represents the position of the cells on one side of the basement membrane. The irregular lines show the position of the blood-vessels.

[21] Tablets and other material for Fehling and additional tests for sugar can be purchased at a drug store. The practical details of these and other tests which assume some knowledge of chemistry, should be learned from some manual on the subject.

[22] The Peritoneum. The intestines do not lie in a loose mass in the abdominal cavity. Lining the walls of this cavity, just as in a general way, a paper lines the walls of a room, is a delicate serous membrane, called the peritoneum. It envelops, in a greater or less degree, all the viscera in the cavity and forms folds by which they are connected with each other, or are attached to the posterior wall. Its arrangement is therefore very complicated. When the peritoneum comes in contact with the large intestine, it passes over it just as the paper of a room would pass over a gas pipe which ran along the surface of the wall, and in passing over it binds it down to the wall of the cavity. The small intestines are suspended from the back wall of the cavity by a double fold of the peritoneum, called the mesentery. The bowels are also protected from external cold by several folds of this membrane loaded with fat. This is known as the great omentum.
The peritoneum, when in health, secretes only enough fluid to keep its surface lubricated so that the bowels may move freely and smoothly on each other and on the other viscera. In disease this fluid may increase in amount, and the abdominal cavity may become greatly distended. This is known as ascites or dropsy.

[23] The human bile when fresh is generally of a bright golden red, sometimes of a greenish yellow color. It becomes quite green when kept, and is alkaline in reaction. When it has been omited it is distinctly yellow, because of its action on the gastric juice. The bile contains a great deal of coloring matter, and its chief ingiedients are two salts of soda, sodium taurocholate and glycocholate.

[24] Nansen emphasizes this point in his recently published work, Farthest North.

[25] We should make it a point not to omit a meal unless forced to do so. Children, and even adults, often have the habit of going to school or to work in a hurry, without eating any breakfast. There is almost sure to be a fainting, or “all-gone” feeling at the stomach before another mealtime. This habit is injurious, and sure to produce pernicious results.

[26] The teeth of children should be often examined by the dentist, especially from the beginning of the second dentition, at about the sixth year, until growth is completed. In infancy the mother should make it a part of her daily care of the child to secure perfect cleanliness of the teeth. The child thus trained will not, when old enough to rinse the mouth properly or to use the brush, feel comfortable after a meal until the teeth have been cleansed. The habit thus formed is almost sure to be continued through life.

[27] “If the amount of alcohol be increased, or the repetition become frequent, some part of it undergoes acid fermentation in the stomach, and acid eructations or vomitings occur. With these phenomena are associated catarrh of the stomach and liver with its characteristic symptoms,—loss of appetite, feeble digestion, sallowness, mental depression, and headache.”—James C. Wilson, Professor in the Jefferson Medical College, Philadelphia.
“Man has recourse to alcohol, not for the minute quantity of energy which may be supplied by itself, but for its powerful influence on the distribution of the energy furnished by other things. That influence is a very complex one.”—Professor Michael Foster.

[28] “When constantly irritated by the direct action of alcoholic drinks, the stomach gradually undergoes lasting structural changes. Its vessels remain dilated and congested, its connective tissue becomes excessive, its power of secreting gastric juice diminishes, and its mucous secretions abnormally abundant.”—H. Newell Martin, late Professor of Physiology in Johns Hopkins University.
“Chemical experiments have demonstrated that the action of alcohol on the digestive fluids is to destroy its active principle, the pepsin, thus confirming the observations of physiologists that its use gives ride to the most serious disorders of the stomach and the most malignant aberrations of the entire economy.”—Professor E. C. Youmans, author of standard scientific works.
“The structural changes induced by habitual use of alcohol and the action of this agent on the pepsin, seriously impair the digestive power. Hence it is, that those who are habitual consumers of alcoholic fluids suffer from disorders o digestion.”—Robert Bartholow, recently Professor of Materia Medica in the University of Pennsylvania.
“Alcohol in any appreciable quantity diminishes the solvent power of the gastric fluid so as to interfere with the process of digestion instead of aiding it.”—Professor W. B. Carpenter, the eminent English physiologist.

[29] “Cirrhosis of the liver is notoriously frequent among drunkards, and is in fact almost, though not absolutely, confined to them.”—Robert T. Edes, formerly Professor of Materia Medica in Harvard Medical College.
“Alcohol acts on the liver by producing enlargement of that organ, and a fat deposit, or ‘hob-nailed’ liver mentioned by the English writers.”—Professor W. B. Carpenter.

[30] Preparation of Artificial Gastric Juice. (a) Take part of the cardiac end of the pig’s stomach, which has been previously opened and washed rapidly in cold water, and spread it, mucous surface upwards, on the convex surface of an inverted capsule. Scrape the mucous surface firmly with the back of a knife blade, and rub up the scrapings in a mortar with fine sand. Add water, and rub up the whole vigorously for some time, and filter. The filtrate is an artificial gastric juice.
(b) From the cardiac end of a pig’s stomach detach the mucous membrane in shreds, dry them between folds of blotting-paper, place them in a bottle, and cover them with strong glycerine for several days. The glycerine dissolves the pepsin, and on filtering, a glycerine extract with high digestive properties is obtained.
These artificial juices, when added to hydrochloric acid of the proper strength, have high digestive powers.
Instead of (a) or (b) use the artificial pepsin prepared for the market by the wholesale manufacturers of such goods.

[31] The cause of the clotting of blood is not yet fully understood. Although the process has been thoroughly investigated we have not yet a satisfactory explanation why the circulating blood does not clot in healthy blood-vessels. The ablest physiologists of our day do not, as formerly, regard the process as a so-called vital, but a purely chemical one.

[32] Serous Membranes.—The serous membranes form shut sacs, of which one portion is applied to the walls of the cavity which it lines; the other is reflected over the surface of the organ or organs contained in the cavity. The sac is completely closed, so that no communication exists between the serous cavity and the parts in its neighborhood. The various serous membranes are the pleura which envelops the lungs; the pericardium which surrounds the heart; the peritoneum which invests the viscera of the abdomen, and the arachnoid in the spinal canal and cranial cavity. In health the serous membranes secrete only sufficient fluid to lubricate and keep soft and smooth the opposing surfaces.

[33] A correct idea may be formed of the arrangement of the pericardium around the heart by recalling how a boy puts on and wears his toboggan cap. The pericardium encloses the heart exactly as this cap covers the boy’s head.

[34] “Alcohol taken in small and single doses, acts almost exclusively on the brain and the blood-vessels of the brain, whereas taken in large and repeated doses its chief effects are always nervous effects. The first effects of alcohol on the function of inhibition are to paralyze the controlling nerves, so that the blood-centers are dilated, and more blood is let into the brain. In consequence of this flushing of the brain, its nerve centers are asked to do more work.”—Dr. T. S. Clouston, Medical Superintendent of the Royal Asylum, Edinburgh.
“Alcoholic drinks prevent the natural changes going on in the blood, and obstruct the nutritive and reparative functions.”—Professor E. L. Youmans, well-known scientist and author of Class Book of Chemistry.

[35] The word “cell” is not used in this connection in its technical signification of a histological unit of the body (sec. 12), but merely in its primary sense of a small cavity.

[36] “The student must guard himself against the idea that arterial blood contains no carbonic acid, and venous blood no oxygen. In passing through the lungs venous blood loses only a part of its carbonic acid; and arterial blood, in passing through the tissues, loses only a part of its oxygen. In blood, however venous, there is in health always some oxygen; and in even the brightest arterial blood there is actually more carbonic acid than oxygen.”—T. H. Huxley.

[37] “Consumption is a disease which can be taken from others, and is not simply caused by colds. A cold may make it easier to take the disease. It is usually caused by germs which enter the body with the air breathed. The matter which consumptives cough or spit up contains these germs in great numbers—frequently millions are discharged in a single day. This matter spit upon the floor, wall, or elsewhere is apt to dry, become pulverized, and float in the air as dust. The dust contains the germs, and thus they enter the body with the air breathed. The breath of a consumptive does not contain the germs and will not produce the disease. A well person catches the disease from a consumptive only by in some way taking in the matter coughed up by the consumptive.”—Extract from a circular issued by the Board of Health of New York City.

[38] “The lungs from the congested state of their vessels produced by alcohol are more subject to the influence of cold, the result being frequent attacks of bronchitis. It has been recognized of late years that there is a peculiar form of consumption of the lungs which is very rapidly fatal and found only in alcohol drinkers.”—Professor H. Newell Martin.

[39] “The relation to Bright’s Disease is not so clearly made out as is assumed by some writers, though I must confess to myself sharing the popular belief that alcohol is one among its most important factors.”—Robert T. Edes, M.D.

[40] Thus the fibers which pass out from the sacral plexus in the loins, and extend by means of the great sciatic nerve and its branches to the ends of the toes, may be more than a yard long.

[41] Remarkable instances are cited to illustrate the imperative demand for sleep. Gunner boys have been known to fall asleep during the height of a naval battle, owing to the fatigue occasioned by the arduous labor in carrying ammunition for the gunner. A case is reported of a captain of a British frigate who fell asleep and remained so for two hours beside one of the largest guns of his vessel, the gun being served vigorously all the time. Whole companies of men have been known to sleep while on the march during an arduous campaign. Cavalrymen and frontiersmen have slept soundly in the saddle during the exhausting campaigns against the Indians.

[42] According to the Annual Report of New York State Reformatory, for 1896, drunkenness among the inmates can be clearly traced to no less than 38 per cent of the fathers and mothers only.
Drunkenness among the parents of 38 per cent of the prisoners in a reformatory of this kind is a high and a serious percentage. It shows that the demoralizing influence of drink is apt to destroy the future of the child as well as the character of the parent.
“There is a marked tendency in nature to transmit all diseased conditions. Thus the children of consumptive parents are apt to be consumptive. But, of all agents, alcohol is the most potent in establishing a heredity that exhibits itself in the destruction of mind and body. There is not only a propensity transmitted, but an actual disease of the nervous system.”—Dr. Willard Parker.

[43] “It is very certain that many infants annually perish from this single cause.”—Reese’s Manual of Toxicology.

[44] If an eye removed from its socket be stripped posteriorly of the sclerotic coat, an inverted image or the field of view will be seen on the retina; but if the lens or other part of the refractive media be removed, the image will become blurred or disappear altogether.

[45] This change in the convexity of the lens is only a slight one, as the difference in the focal point between rays from an object twenty feet distant and one four inches distant is only one-tenth of an inch. While this muscular action is taking place, the pupil contracts and the eyeballs converge by the action of the internal rectus muscles. These three acts are due to the third nerve (the motor oculi). This is necessary in order that each part should he imprinted on the same portion of the retina, otherwise there would be double vision.

[46] The Germans have a quaint proverb that one should never rub his eyes, except with his elbows!

[47] “The deleterious effect of tobacco upon eyesight is an acknowledged fact. The Belgian government instituted an investigation into the cause of the prevalence of color-blindness. The unanimous verdict of the experts making the examination was that the use of tobacco was one of the principal causes of this defect of vision.
“The dimness of sight caused by alcohol or tobacco has long been clinically recognized, although not until recently accurately understood. The main facts can now be stated with much assurance, since the publication of an article by Uhthoff which leaves little more to be said. He examined one thousand patients who were detained in hospital because of alcoholic excess, and out of these found a total of eye diseases of about thirty per cent.
“Commonly both eyes are affected, and the progress of the disease is slow, both in culmination and in recovery.... Treatment demands entire abstinence.”—Henry D. Noyes, Professor of Otology in the Bellevue Hospital Medical College, New York.

[48] “The student who will take a little trouble in noticing the ears of the persons whom he meets from day to day will be greatly interested and surprised to see how much the auricle varies. It may be a thick and clumsy ear or a beautifully delicate one; long and narrow or short and broad, may have a neatly formed and distinct lobule, or one that is heavy, ungainly, and united to the cheek so as hardly to form a separate part of the auricle, may hug the head closely or flare outward so as to form almost two wings to the head. In art, and especially in medallion portraits, in which the ear is a marked (because central) feature, the auricle is of great importance”—William W. Keen, M.D., editor of Gray’s Anatomy.

[49] The organ of Corti is a very complicated structure which it is needless to describe in this connection. It consists essentially of modified ephithelial cells floated upon the auditory epithelium, or basilar membrane, of the cochlea. There is a series of fibers, each made of two parts sloped against each other like the rafters of a roof. It is estimated that there are no less than 3000 of these arches in the human ear, placed side by side in a continuous series along the whole length of the basilar membrane. Resting on these arches are numbers of conical epithelial cells, from the free surface of which bundles of stiff hairs (cilia) project. The fact that these hair-cells are connected with the fibers of the cochlear division of the auditory nerve suggests that they must play an important part in auditory sensation.

[50] The voices of boys “break,” or “change,” because of the sudden growth or enlargement of the larynx, and consequent increase in length of the vocal cords, at from fourteen to sixteen years of age. No such enlargement takes place in the larynxes of girls: therefore their voices undergo no such sudden change.

[51] This experiment and several others in this book, are taken from Professor Bowditch’s little book called Hints for Teachers of Physiology, a work which should be mastered by every teacher of physiology in higher schools.

[52] The teacher or student who is disposed to study the subject more thoroughly and in more detail than is possible in a class text-book, will find all that is needed in the following excellent books, which are readily obtained by purchase, or may be found in the public libraries of larger towns: Dulles’ Accidents and Emergencies; Pilcher’s First Aid in Illness and Injury; Doty’s Prompt Aid to the Injured; and Johnston’s “Surgical Injuries and Surgical Diseases,” a special article in Roosevelt’s In Sickness and in Health.

[53] “A tourniquet is a bandage, handkerchief, or strap of webbing, into the middle of which a stone, a potato, a small block of wood, or any hard, smooth body is tied. The band is tied loosely about the limb, the hard body is held over the artery to be constricted, and a stick is inserted beneath the band on the opposite side of the limb and used to twist the band in such a way that the limb is tightly constricted thereby, and the hard body thus made to compress the artery (Fig. 160).
“The entire circumference of the limb may be constricted by any sort of elastic band or rubber tube, or any other strong elastic material passed around the limb several times on a stretch, drawn tight and tied in a knot. In this way, bleeding may be stopped at once from the largest arteries. The longer and softer the tube the better. It requires no skill and but little knowledge of anatomy to apply it efficiently.” Alexander B. Johnson, Surgeon to Roosevelt Hospital, New York City.

[54] Corrosive sublimate is probably the most powerful disinfectant known. A solution of one part in 2000 will destroy microscopic organisms. Two teaspoonfuls of this substance will make a solution strong enough to kill all disease germs.

[55] The burning of sulphur produces sulphurous acid, which is an irrespirable gas. The person who lights the sulphur must, therefore, immediately leave the room, and after the lapse of the proper time, must hold his breath as he enters the room to open the windows and let out the gas. After fumigation, plastered walls should be white-washed, the woodwork well scrubbed with carbolic soap, and painted portions repainted.

[56] Put copperas in a pail of water, in such quantity that some may constantly remain undissolved at the bottom. This makes a saturated solution. To every privy or water-closet, allow one pint of the solution for every four persons when cholera is about. To keep privies from being offensive, pour one pint into each seat, night and morning.

[57] “While physiology is one of the biological sciences, it should be clearly recognized that it is not, like botany or zoology, a science of observation and description; but rather, like physics or chemistry, a science of experiment. While the amount of experimental instruction (not involving vivisection or experiment otherwise unsuitable) that may with propriety be given in the high school is neither small nor unimportant, the limitations to such experimental teaching, both as to kind and as to amount, are plainly indicated.
“The obvious limitations to experimental work in physiology in the high school, already referred to, make it necessary for the student to acquire much of the desired knowledge from the text-book only. Nevertheless, much may be done by a thoughtful and ingenious teacher to make such knowledge real, by the aid of suitable practical exercises and demonstrations.”—Report of the Committee of Ten on Secondary School Studies.

[58] This ingenious and excellent experiment is taken from the New York School Journal for May, 1897, for which paper it was prepared by Charles D. Nason, of Philadelphia.