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General Plan of the Circulation. 
 
AUTHORIZED PHYSIOLOGY SERIES, No. J. 
 
 THE OUTLINES 
 
 OF 
 
 ANATOMY, PHYSIOLOGY, AND 
 . HYGIENE 
 
 V 
 
 BEING AN EDITION OF 
 THE ESSENTIALS OF ANATOMY, PHYSIOLOGY, AND HYGIENE 
 
 REVISED TO CONFORM TO THE LEGISLATION MAKING THE 
 
 EFFECTS OF ALCOHOL AND OTHER NARCOTICS UPON THE HUMAN SYSTEM 
 
 A MANDATORY STUDY IN PUBLIC SCHOOLS 
 
 BY 
 
 ROGER S. TRACY, M. D. 
 
 REGISTER OF RECORDS OF THE NEW YORK CITY HEALTH DEPARTMENT J 
 
 AUTHOR OF " HAND-BOOK OF SANITARY INFORMATION 
 
 FOR householders" 
 
 NEW YORK •:• CINCINNATI •:• CHICAGO 
 
 AMERICAN BOOK COMPANY 
 
3€ 
 
 INDORSEMENT. 
 
 The ' ' Authorized Physiology Series " consists of : 
 NOo I.—" Health for Little Folks." For Primary Grades. 
 
 II. — " Lessons in Hygiene," \ 
 
 A special edition of "How we Live," >- For Intermediate Grades, 
 by Johonnot and Bouton. ) 
 
 in.— "The Outlines of Anatomy, Physi- ] For High - Schools and 
 ology, and Hygiene," by Roger S. - Advanced Classes in 
 Tracy, M. D. ) Common Schools. 
 
 In this series good judgment has been shown in the selection of facts that 
 should be taught each grade, and in representing these facts in language 
 which the pupils of the grades for which the books are designed can com- 
 prehend. 
 
 The treatment of the subjects of anatomy and physiology in the high- 
 school book covers the usual ground ; in the books of the lower grades it 
 does not unduly preponderate, but it is abundantly ample to enable the 
 pupil to comprehend the topic which is the real object of the study, viz., the 
 laws of health, and the nature of alcoholic drinks and other narcotics, and 
 their effects upon the human system. The treatment of this part of the 
 subject, in each book of the series, is full, clear, and in harmony with the 
 latest teachings of science, and represents the spirit as well as the letter of 
 the laws that require these truths taught all pupils in all schools. We are 
 therefore happy to indorse and commend the same for use in schools. 
 
 MARY H. HUNT, 
 National and International Superintendent 
 Department of Scientific Instruction of the 
 Woman''s Christian Temperance Union. 
 
 Albert H. Plumb, D. D. 
 Daniel Dorcheste 
 Hon. William E. 
 Rev. Joseph Cook, 
 
 Daniel Dorchester, D. D. \ ., . , ■, r ^i tt -^ ^ 04- *.. 
 
 ' y Advisory board for the United States. 
 
 Hon. William E. Sheldon. ' 
 
 Copyright, 1884, 1886, 1889, 
 By D. APPLETON AND COMPANY. 
 
 T. OUTLINES. 
 
 printefe b? 
 
 S). Bppleton &. Company 
 
 IRevc l!?or??, "CI. S. B. 
 
PREFACE. 
 
 It has been my aim In preparing this volume to 
 compress within the narrowest space such a clear 
 and intelligible account of the structures, activities, 
 and care of the human system as is essential for the 
 purposes of general education. I have also sought 
 to present the facts and principles of the subject in 
 such a natural order as will best subserve the true 
 ends of scientific education. Useful books of in- 
 formation upon physiology are already numerous, 
 but they are too generally deficient in making the 
 science valuable as a means of mental training. Of 
 course, the great object of physiology is to teach how 
 to preserve health, but this is not best done by 
 merely memorizing rules. The rules must be sup- 
 ported by reasons, and if there is not some thorough 
 understanding of the mechanism and powers of the 
 human body, such as will task the efforts of the 
 student, the real fruits of knowledge will not be 
 gained. 1 have accordingly given prominence to 
 the anatomical and physiological facts which are 
 necessary preliminaries to instruction in hygiene, 
 and in the reasonings upon these facts I have aimed 
 to attract and interest the pupil, to teach him some- 
 thing of the scientific methods of approaching the 
 
ivr PREFACE, 
 
 subject, and to connect new acquisitions logically 
 with those already gained, so that the knowledge 
 of the subject may become, as it were, organized 
 into faculty in the minds of the students. So im- 
 portant has it seemed to me to impress deeply upon 
 the pupil's mind the laws of connection and depend- 
 ence among the various parts of the living system 
 that I have thought it best to present this view, in 
 outline, at the very outset. I have, therefore, pre- 
 fixed to the volume a General Analysis, which, 
 while it serves as a table of contents, is interspersed 
 with running comments explaining the general re- 
 lations of the different organs and processes, and I 
 recommend that this analysis be carefully read by 
 the pupil, so that he may become familiar with its 
 argument before proceeding to the detailed study 
 of the text. 
 
 One of the greatest modern reforms in scientific 
 study is undoubtedly that which makes it more 
 and more objective, so that the student shall con- 
 stantly confirm the knowledge he gets from the 
 book by reference, as far as possible, to the objects 
 themselves, making his acquaintance with them 
 direct, and his information real. The various sci- 
 ences lend themselves to this mode of study in 
 different degrees ; chemistry and physics favoring 
 experiment, and botany offering systematic obser- 
 vation more than any other scientific subjects. 
 Physiology is less favorable' to the objective method. 
 For the purpose of ordinary ■ education, it must be 
 chiefly taught from the book, with such accompani- 
 ments of lectures and illustrations by. charts as the 
 circumstances will allow. But even here much may 
 ^e done to give the, pupil morje correct ideas of the 
 
PREFACE. V 
 
 elements of the subject than can be obtained from 
 the book alone. A good manikin is an invaluable 
 help to the popular study of anatomy and physiol- 
 ogy. Human dissection being out of the question, 
 the manikin, which can be taken to pieces so as to 
 show all the organs in their situations, connections, 
 and relative dimensions, will afford the pupil a vivid 
 and exact conception of the dependent parts of the 
 living body, and make his physiological knowledge 
 truthful and actual. A manikin for school pur- 
 poses costs about $2 50, and may be imported from 
 Paris,^ where they are made, free of duty for educa- 
 tional institutions. 
 
 A great deal is also to be learned from such 
 rough dissections of organic tissue and structures 
 as may be made anywhere. Every butcher's shop 
 is full of specimens of all parts of animals, that can 
 be cheaply obtained for examination, and parents 
 and teachers should encourage pupils to make such 
 rude dissections as are practicable, and will help to 
 give correct ideas of the relations and functions of 
 the different organs. 
 
 The study of the minuter parts of organized 
 beings with the microscope, histology as it is called, 
 has come into great prominence in modern times, 
 and may be said to have revolutionized the science 
 of life. No class in physiology should be without a 
 microscope for the direct study of cell-structures 
 and the finer tissues of both plants and animals. A 
 suitable instrument, with a magnifying power of 
 three hundred and fifty diameters, will show the 
 circulation in the web of a frog's foot, and open a 
 new world of fascinating and wonderful observation, 
 
 *Auzoux is the principal manufacturer of these models. 
 
vi PREFACE. 
 
 while it may be bought for sixteen dollars. Micro- 
 scopic preparations of blood-corpuscles, muscular 
 and nervous tissues, and sections of organs may be 
 got for about twenty cents apiece, but it is desirable 
 that the pupil should not rely upon these, but should 
 learn the method of preparing and mounting objects 
 himself. The microscope is not to be recommended 
 as a mere toy to amuse idle curiosity ; there is work 
 connected with it which is in a high degree educa- 
 tional. It cultivates critical observation and careful 
 manipulation, and is invaluable as a means of self- 
 education. The little hand-book of Phin will be 
 found useful in guiding beginners with this instru- 
 ment. 
 
 In compliance with the laws of many States re- 
 quiring the study in schools of " physiology and 
 hygiene with special reference to the nature of 
 alcoholic drinks and other narcotics, and their 
 effects upon the human system," much additional 
 matter relating to that subject will be found in this 
 book. In its preparation the author has had the 
 valuable co-operation of Mrs. Mary H. Hunt, Su- 
 perintendent of the National and International De- 
 partment of Scientific Instruction of the Woman's 
 Christian Temperance Union, who has kindly gone 
 over the entire book, and whose familiarity with 
 the subject and with the laws relating thereto has 
 given especial importance to her suggestions re- 
 garding the selection and arrangement of the new 
 matter. 
 
 The illustrations are largely copied from Gray's 
 ''Anatomy," though I am also indebted to Dalton's 
 '' Physiology," to Flint's *' Physiology," to Ranney's 
 "Applied Anatomy of the Nervous System," to 
 
PREFACE. vii 
 
 Riidinger's " Topographisch-Chirurgische Anato- 
 mic," and to Neumann's " Hand-Book of Skin Dis- 
 eases." Many of the figures I have altered to suit 
 my purpose, and the necessary descriptions are so 
 inscribed upon or near them as to do away with 
 the inconvenience of lettered references. A few of 
 the cuts are original. 
 
 For the use of material other than the illustra- 
 tions, I have to acknowledge m}- indebtedness to 
 Flint, Beaumont, Strieker, Neumann, RUdinger, 
 Paget, Maudsley, Reynolds, Aitken, Huxley, Soel- 
 berg Wells, Uhle and Wagner, Foster, and espe- 
 cially to Dalton. 
 
 R. S. T. 
 
GENERAL ANALYSIS. 
 
 Part I.— Introduction. 
 
 Gives certain necessary definitions, and describes the cell 
 and its properties as being the real basis of all more fully 
 developed living organisms. 
 
 *^"^"^'^ PAGE 
 
 I. Definitions ... t 
 
 II. Minute Structure of the Body ..... 5 
 
 Part II.— Organs of Motion. 
 
 A large body entirely composed of cells would be a soft, 
 jelly-like mass, incapable of locomotion or of self-protection. 
 But to obtain food it must be able to move from place to place, 
 and also to move its different parts with reference to one an- 
 other. For these purposes there must be points of resistance 
 and points of support. These points are furnished by the 
 bones, which act as levers, the joints being the fulcra. 
 
 I. Bones in General . . jj 
 
 II. Particular Bones. — Joints . . . . . .17 
 
 III. Injuries of Bones and Joints 27 
 
 But levers alone are of no use. The bones form a strong 
 framework for the body, but they can not move themselves. 
 To produce motion, organs are required, which can become 
 longer or shorter, under var>ing circumstances. Such organs 
 are the muscles. 
 
 IV. Muscles . . , , . „ ,0 
 
 • » • » o o o c 32 
 
X GENERAL ANALYSIS. 
 
 Part III. — Organs of Repair. 
 
 Energy is never lost or created. If the body loses energy 
 in one way, it must gain it in another, or it will soon be worn 
 out. Every muscular contraction wastes a certain amount of 
 material, and an equal amount must be again Siipplied. This 
 is done in the form of food. 
 
 CHAPTER PAGE 
 
 I. Food. — Supply and Waste 46 
 
 But food, as it exists outside of the body, can not be ap- 
 propriated by the wasting tissues. It must hrst be prepared. 
 The process of preparation is called digestica. 
 
 II. Origin and. Nature of Alcoholic Drinks. . . 54 
 
 III. Mastication. — Swallowing 65 
 
 IV. Stomach-Digestion .... ... 72 
 
 V Intestinal Digestion 96 
 
 After the food has been so far prepared, it must in some 
 way be carried through the body to all its different parts, that 
 each may take what it requires for its sustenance. This is 
 accomplished by means of a fluid which passes continually 
 and rapidly through all parts of the body, carrying the nutri- 
 tious material. This fluid is the blood. 
 
 VI. The Blood ri2 
 
 But the blood, besides carrying nutriment, must also re- 
 move the waste and used-up matters, which injure the health 
 if they remain in the body. There is also a gas, called oxygen, 
 which is found to be necessary to the processes of nutrition. 
 This gas exists in the air, and is taken from the air into the 
 blood. The process, by which the blood gets rid of impurities 
 and takes in oxygen, is called respiration. 
 
 VII. Respiration 118 
 
 VIII. Asphyxia . . 141 
 
 The blood can not visit the different parts of the body of 
 its own accord. It is a fluid, and must be propelled. There 
 are organs for this purpose, which keep up what is called the 
 circulation of the blood. 
 
 IX. The Heart 146 
 
 X. The Blood-Vessels 159 
 
 XI. Disorders of Circulation. — H.-emorrhage. . . 175 
 
GENERAL ANALYSIS. 
 
 XI 
 
 Part W . — Organs of Co-ordination. 
 
 The motions of the body, the continual waste and supply, 
 and the processes of digestion and circulation, form a very 
 comphcated series of phenomena. Certain parts of the body 
 require more blood at certain times than at others. Processes 
 taking place at the same time in different parts of the body 
 might conflict and interfere with each other. We find, there- 
 fore, a system of organs whose function it is to harmonize 
 or co-ordinate all these processes, to produce a sympathy 
 between them, and make them all work together for the com- 
 mon interest. This is the nervous system. 
 
 CHAPTER PAGE 
 
 I. Nerve-Substance 1S9 
 
 II. The Sympathetic System 
 
 III. The Spinal Cord . 
 
 IV. The Brain 
 
 V, Special Nerves. — Hygiene 
 
 . 199 
 . 20S 
 . 219 
 . 231 
 
 Part V. — Organs of Protection. 
 
 All the organs pre\-iously described form a vtxy delicate 
 structure, which is continually exposed to external injurious 
 influences. It is exposed to heat and cold, to blows and 
 scratches, and all manner of violence, and so we find it en- 
 wrapped in a strong covering, which protects it from these 
 influences, partly by its own strength and toughness, and 
 partly by certain organs which are imbedded in it, and form 
 a part of it. This organ is the skin, with the various glands 
 and other structures found therein. 
 
 I. The Skin 252 
 
 II. Functions and C.\re of the Skin .... 258 
 
 Part VI.— Organs of Perception. 
 
 The body being now complete, so far as its movements, 
 nutrition, co-ordination of parts, and protection are concerned, 
 we see that, as its food must come from outside, there must 
 be organs to bring it into relation with the external world, lo 
 aid it in its search for food, and to protect it during the search. 
 These organs are the organs of the senses, which bring us 
 into relation with what is outside of us, and in this way are 
 the sources of our ideas. The elementary one of these 
 senses is touch, tlie others being only modifications of it. 
 
xii GENERAL ANALYSIS, 
 
 CHAPTER PAGE 
 
 I. Touch, Taste, Smell 274 
 
 II. Hearing 283 
 
 III. Sight . . . o 291 
 
 Part VII. — Organ of Communication . . . .309 
 
 The body being now practically complete, we find still 
 another organ, whose function it is to enable us to communi- 
 cate our ideas to others. This organ is the larynx, the organ 
 of speech, that wonderful faculty which has had so much to 
 do with creating the tremendous gap that exists between man 
 and the lower animals. 
 
 Table of the Bones 314 
 
 Questions 315 
 
 Glossary 331 
 
 Index . 345 
 
PART I. 
 INTR on UC TION, 
 
 CHAPTER I. 
 
 DEFINITIONS. 
 
 I. Definitions.^The science which tells us about 
 the different parts of the body, what they are, where 
 they are, and how they look, is called anatomy. 
 
 The science which tells us about the purpose of 
 these parts, what they do and how they do it, is 
 called physiology. 
 
 The science which tells us what will interfere 
 with the working of these parts, w^hat will injure 
 and what will help them, and how to avoid what 
 is hurtful, is called hygieite. 
 
 A part of the body, which is so small that when 
 it has been separated from other parts it can not be 
 further subdivided without the destruction of its 
 organization, is called an anatomical clement^ as a 
 cell or a fiber. 
 
 Two or more anatomical elements, united or in- 
 terwoven so as to form one substance, make what 
 is called tissue ; e. g., fatty tissue, connective tissue, 
 etc. 
 
 A part of the bodv, which is made up of ana- 
 tomical elements and tissues, together forming one 
 
2 INTRODUCTION, 
 
 whole, which can be separated from the rest of the 
 body as an entire mass, and which performs a par- 
 ticular function, is called an organ; as, the liver, 
 the heart, a bone, or a muscle. 
 
 A number of organs, similar in structure, but 
 differing in size and shape, and spread throughout 
 the body, are called a system ; as, the nervous sys- 
 tem, the arterial system, etc. 
 
 Several organs, which differ in structure but 
 are so connected as to work together for a particu- 
 lar end, are called an apparatus ; thus, the stomach, 
 liver, etc., constitute together the digestive appa- 
 ratus. 
 
 • The work that is done by a healthy organ in 
 the body is called its function ; e. g., the secretion 
 of bile is a function of the liver. 
 
 Any substance whose nature it is when absorbed 
 into the blood to injure health, or destroy life, is 
 called a poison. 
 
 A narcotic is something that, when introduced 
 into a living organism, deadens its sensitiveness, 
 and so diminishes its ability to perform its natural 
 functions. 
 
 When a poison does its injurious work wholly 
 or in part by paralyzing or deadening the nervous 
 system, it is called a narcotic poison. 
 
 As narcotic poisons will be frequently referred 
 to in the following pages, a brief description of 
 those best known is given here. 
 
 Opiiwi, a powerful narcotic, is a blackish or 
 brownish gummy substance obtained by evaporat- 
 ing the milky juice of the poppy. Its composition 
 is very complex, one of the principal substances it 
 contains being morphia (or morphine), usually form- 
 
DEFINITIONS. 3 
 
 ing about ten per cent of its weight. Laudanum is 
 an alcoholic tincture of opium, twenty-five drops 
 being about the equivalent of one grain of the drug. 
 Paregoric is a compound tincture sweetened with 
 honey and flavored with anise, containing about 
 one grain of opium in each tablespoonful. 
 
 Alcohol, a product of fermentation, is a narcotic 
 poison. Its great affinity for water, and its power 
 of coagulating albumen, render it destructive of 
 living tissues with which it is brought in contact. 
 It is a colorless, transparent fluid, of light specific 
 gravity (0.7938), is very inflammable, burning with 
 a smokeless blue flame, and has been frozen at the 
 exceedingly low temperature of —203° Fahr., when 
 it solidifies into a white mass. Pure alcohol is very 
 difficult to obtain, on account of its strong affinity 
 for water. It is composed of carbon, hydrogen, 
 and oxygen (C^HgO). 
 
 There are various kinds of alcohol — that which 
 imparts the intoxicating quality to wines, etc., being 
 known as ethyl alcohol. Other forms are found in 
 rotting wood, in decaying grains, etc. For further 
 account of the origin and nature of this substance 
 and of drinks containing it, see Part III, Chapter II. 
 
 Tobacco is the dried leaf of a plant called by bot- 
 anists Nicotiana Tabaciiin. 
 
 The tobacco-leaf is cured in various ways, and 
 put through manufacturing processes which affect 
 its qualit}'. Like opium, it is a very complex sub- 
 stance, but the active ingredient, which renders the 
 use of it so attractive to many people, is called 
 nicotine. This is a volatile, colorless liquid of a 
 specific gravity of 1.018, which turns brown on ex- 
 posure to the air. It constitutes from one to nine 
 
4 INTRODUCTION. 
 
 per cent of the weight of the tobacco, the amount 
 varying greatly in different specimens. Nicotine 
 is a deadly poison like Prussic acid, destroying life 
 in small doses with great rapidity. 
 
 Chloroform (CHCI3) is a narcotic poison, obtained 
 by distilling chloride of lime, water, and alcohol 
 together. It is a thin, colorless liquid (specific 
 gravity, 1.525), of agreeable odor and sweetish 
 taste. When inhaled, the vapor produces tempo- 
 rary insensibility. 
 
 Chloral (CCI3CHO) is made by passing chlorine 
 gas into ethyl alcohol. It is a thin, oily, colorless 
 liquid, of a pungent odor, but almost tasteless 
 (specific gravity, 1.502). It is used by physicians 
 to induce sleep. 
 
CHAPTER IL 
 
 MINUTE STRUCTURE OF THE BODY. 
 
 2. Minute Structure of the Body. — The body, 
 when its parts are examined with the microscope, is 
 found to be made up mainly of cells, fibers, Tind fluids. 
 The cell is considered to be the original element 
 out of which every other element in the body is 
 formed ; fibers, fluids, etc., being derived from or 
 generated by previously existing cells. 
 
 The different consistency of different organs is 
 due to the varying proportions of these elements. 
 If the fibers are in the largest proportion, the tissue 
 or organ will be hard, 
 tough, and elastic ; if the 
 cells form the greatest 
 part, it will be soft, melas- 
 tic, and vielding. 
 
 3. The Fiber. — The 
 fiber proper (Fig. i) is a 
 slender thread, composed 
 of a hard whitish or yel- 
 lowish substance, some- 
 times elastic and some- 
 times not, but very tough 
 
 and strong. Fibers are found in almost all parts of 
 
 the body, binding the parts of organs together, and 
 2 
 
 Fig. I. — Fibrous tissue. 
 
6 INTRODUCTION. 
 
 constituting almost the entire mass of some parts, 
 as the tendons or sinews, for instance. The word 
 " fiber " is also used of certain portions of muscular 
 and nervous tissue, in a different sense from the one 
 given above. These differences will be explained 
 hereafter. 
 
 4. The Cell. — The cell is the most important 
 structure in the living body, whether animal or 
 vegetable. Life resides in the cell ; and every 
 plant or animal may really be looked upon as a 
 mass composed of billions of cells, each of which 
 is alive, and each of which has its own part to play 
 in the nourishment of itself and the rest of the 
 body. 
 
 A single cell * (Figs. 2 and 3) is a portion of al- 
 
 FiG. 2. — Epithelium from the mouth. 
 
 Fig. 3. — Liver-cells. 
 
 buminous matter, which has by some been called 
 protoplasmjf sometimes surrounded by a thin mem- 
 
 * Scrape gently the surface of the tongue, and put the fluid thus 
 obtained under the microscope. Plenty of cells will then be seen, 
 similar in appearance to those shown in Fig. 1. 
 
 \ Pro toplas7n^ from two Greek words, signifying the first (or primi- 
 tive) formed matter, because, so far as we know at present, it is the 
 
MINUTE STRUCTURE OF THE BODY. j 
 
 brane and sometimes not, and usually having in its 
 interior what looks like a smaller celL This small 
 body is called the nu'clnis of the larger one. In- 
 side of the nucleus is often found another exceed- 
 ingly minute body, or sometimes a mere shining 
 point, called the mLcle'olus (see Fig. 52). 
 
 5. Protoplasm. — The protoplasm, or matter 
 which forms the mass of a cell, is of a semi-fluid 
 consistency, somewhat like jelly, and can not be dis- 
 tinguished by chemical tests from albumen. Hence 
 it is said to be albuminous in its nature, resembling 
 to some extent the white of a raw ^^^, which is 
 almost pure albumen. All cells are so exceedingly 
 small, being rarely more than ^^^q of an inch in 
 diameter, that we really know very little of their 
 minute structure, on account of the difficulty of in- 
 vestigating them with such imperfect instruments 
 as we have. 
 
 6. Granular Matter. — The points just mentioned 
 are the most characteristic of the cell. Besides the 
 cells, fibers, and fluids, there is a great deal of mat- 
 ter in different parts of the body, which has been 
 formed or deposited by the cells at different periods 
 of their growth. This matter, under the micro- 
 scope, sometimes appears granular, or as if made 
 up of very minute specks, and sometimes almost 
 transparent. Some of it is found to be fat in a 
 finely-divided state, but some of it is albuminouSj 
 and some of it contains mineral matter in consider- 
 able amount. 
 
 7. DifTerence between Living and Dead Cells. — 
 A Hving and a dead cell look precisely alike, except- 
 
 simplest form of living matter, and makes up the only part of all ani- 
 mal and vegetable bodies which shows signs of life. 
 
8 
 
 IN TROD UCTION. 
 
 ing that the dead one is motionless. A living cell, 
 minute as it is, frequently possesses the power of 
 independent motion, or at least is able to change 
 its form (Fig. 4). It also can take up nourishment 
 into its mass, and can propagate itself. The move- 
 ments of the cell can be 
 beautifully seen in the 
 white cells of the blood, 
 which will be described 
 hereafter. 
 
 8. Growth of Cells. — 
 A cell propagates itself in 
 several ways ; one of the 
 most common is by divid- 
 ing into two parts. This 
 operation has been often 
 watched under the micro- 
 scope by skilled observers. The change is seen to 
 begin in the nucleus, and, as that divides by a line 
 through its center, the protoplasm of the cell ar- 
 ranges itself in halves around each part of the nu- 
 cleus, its surface dipping in toward the center, 
 until finally the approaching surfaces meet and the 
 
 Fig. 4. — White cells in motion. 
 
 Fig. 5. — Cell dividing and forming two new cells. 
 
 cell is divided into two new cells, each with its nu- 
 cleus, and in every way complete (Fig. 5). This 
 division goes on with great rapidity. The secre- 
 tion from the throat and nose in nasal catarrh is 
 composed mainly of cells, which are thrown off by 
 millions during an inflammation. 
 
MINUTE STRUCTURE OF THE BODY. 9 
 
 9. Other Properties of Cells. — Cells also possess 
 other powers which enable them to perform their 
 important offices in the body. They are able to 
 select certain substances out of a general mixture, 
 and reject others. This is done by the liver-cells, 
 for example, which secrete the bile, and by the cells 
 of those glands which secrete the saliva. The cells 
 of the brain act, in some unexplained way, as the 
 instruments of thought. The cells in the kidneys 
 separate matters from the blood which are very 
 poisonous, and have to be expelled from the S3'S- 
 tem. 
 
 The power of division and of numerical increase 
 of cells is not unlimited. If a portion of the body 
 is wounded, it is healed again by the active efforts 
 of the uninjured cells in the borders of the wound. 
 The action of these cells ceases, however (if the part 
 is healthy), to reproduce substance, when the part 
 made vacant by the injury has been filled up. Why 
 does this action of the cells, once started, not con- 
 tinue until the body dies ? Why does the replace- 
 ment of tissue cease as soon as the former surface 
 is reached ? This question can not at present be 
 answered.* 
 
 Thus we see that the cell, minute as it is and 
 simple as it is, performs its office in the body with 
 
 * When the cells in the borders of a wound or sore are not in a 
 healthy condition, they sometimes increase in number verj' rapidly, but 
 the new cells, instead of being like the older ones, are larger, chiefly ow- 
 ing to the greater amount of fluid in their interior. This makes them 
 soft and spongy, and seems to interfere with their functions. They do 
 not nourish themselves properly, and they increase and grow beyond 
 the limit where they should stop, and where, if they were healthy, they 
 would stop. This unhealthy growth is what is known as proud fleshy 
 and it has to be repressed by proper surgical treatment. 
 
lO INTRODUCTION. 
 
 care and evidence of forethought and intention. It 
 does what is necessary and no more. It does not 
 act blindly. It does -all it does with a purpose. 
 Where and what is the intelligence that directs the 
 active living cell to repair so far and no farther, to 
 eat this and reject that, to multiply up to a certain 
 point and then stop, and, most wonderful of all, to 
 take upon itself the duties of other cells when they 
 are sick and unable to act,^ and stop performing 
 these extra duties, when the other cells recover? 
 
 10. Effect of Alcohol and Tobacco on Living 
 Cells. — The cells which compose the mass of the 
 body, being very delicate in their structure, are 
 easily acted upon by whatever comes in contact 
 with them. If other substances besides those con- 
 tained in our natural food and drink are introduced 
 into the body, the cells are likely to be injuriously 
 affected ; and this is especially true of narcotics, of 
 which alcohol and tobacco are the most universally 
 used. These substances blunt the sensitiveness of 
 these cells, retarding the changes in their interior, 
 hindering their appropriation of food and elimina- 
 tion of waste matters, and therefore preventing 
 their proper development and growth. The more 
 recently formed such cells are, the less are their 
 powers of resistance ; so that in young persons 
 who are growing the effect of such drugs is espe- 
 cially potent and harmful. 
 
 * When the kidneys, for instance, are diseased, so that the excretion 
 of urine is interfered with, it is found that some of the poisonous mat- 
 ters which usually pass out through them are ejected from the body 
 through the lungs and skin. In such cases, physicians try to assist this 
 process by inducing active perspiration, so as to relieve the kidneys 
 from work as much as possible, and allow them to rest until they get 
 well. 
 
PART II. 
 
 ORGANS OF MOTION. 
 
 CHAPTER I. 
 
 BOXES. — GENERAL STRUCTURE. 
 
 11. Uses of the Bones. — If the body were com- 
 posed merely of cells, such as have been described, 
 with fibers and fluids, it would be a shapeless, jelly- 
 like mass, incapable of locomotion, and of self-pro- 
 tection. There is a necessity, in such a large mass, 
 of points of support and resistance, and the organs 
 or tissues which furnish such points must be tough, 
 hard, and elastic. Such organs are the bones, which 
 form the framework of the body and determine its 
 shape and size. Their most important offices are 
 two in number, viz., to act as levers and points of 
 support and action for the muscular parts, and to 
 protect the soft and delicate organs from external 
 injury. 
 
 12. Living and Dead Bone. — A bone, as we 
 usually see it outside the body, is as different from 
 a living bone as the skin of a corpse is from the liv- 
 ing skin. We usually see it deprived of blood, 
 while in the hving body it is full of it, and is of a 
 pinkish-white color externally, and deep red within. 
 
 13. Composition of Bone. — To accomplish the 
 
12 ORGANS OF MOTION. 
 
 two purposes above mentioned, bones must be hard 
 and tough, in order to maintain their stiffness when 
 the muscles pull upon them, and also to be able to 
 resist external blows. They must also be in some 
 degree elastic, or they would be too brittle for use, 
 and would snap in two under great pressure. Ac- 
 cordingly, we find all bones composed of two kinds 
 of material, so thoroughly mingled and united that, 
 when either kind is removed, the bone still retains 
 its peculiar shape and size, although of course it 
 does not weigh as much as before. About two 
 thirds of the weight of every bone in the adult con- 
 sists of earthy substances, mostly lime phosphate 
 and lime carbonate, and the remaining third of ani- 
 mal matter, part of which can be separated from 
 the rest of the bone by long boiling, and is known 
 as gelatine. 
 
 If a bone be burned in a hot fire, all of the ani- 
 mal matter will be destroyed, and the earthy mat- 
 ters left. These Avill still retain the shape of the 
 bone, but will be Avhite in color, and will easily 
 break and crumble in the fingers. If a bone, on 
 the other hand, be soaked for a time in dilute hy- 
 drochloric acid, all the earthy matter will be dis- 
 solved out, and the animal portion left. This, as in 
 the other case, will retain the shape of the bone, 
 but will be flexible and tough, and may even be 
 tied in a knot. 
 
 By the combination of these two kinds of mat- 
 ter, then, the bone is made hard, tough, and elastic, 
 and admirably adapted to its uses in the body. 
 
 14. The Composition of Bone varies with Age. 
 — In infants and children, the amount of animal mat- 
 ter in the bones is proportionately greater than in 
 
BONES.— GENERAL STRUCTURE. 13 
 
 the adult, and so the bones of very young people 
 will often bend Avhen injured, instead of breaking. 
 Surgeons call this the " green-stick " fracture, be- 
 cause the bone is bent like a green twig, only a small 
 portion of it on the outside of the bend being broken 
 or torn apart. As a person grows older, the amount 
 of earthy matter increases, until in old people the 
 bones become very brittle, and break with very 
 slight blows. 
 
 15. Varieties of Bone and their Structure. — 
 Bones are divided, according to their shape, into 
 long bones, sJiort bones, flat bones, and a fourth kind, 
 called irregular, which combine qualities belonging 
 to the other classes. The long bones are found only 
 in the limbs, and are the most important to the sur- 
 geon, as it is in them that most fractures and other 
 injuries occur. They are divided into a shaft and 
 extremities. The shaft of every long bone consists 
 of hard, compact, closely-grained tissue, somewhat 
 like ivor}'. This is the only part used in the man- 
 ufacture of ornaments, buttons, knife-handles, etc. 
 The extremities of these bones form the joints, and, 
 in order to give greater security and a greater 
 purchase to the muscles as well as a greater surface 
 for their attachment, the ends are much larger than 
 the shaft. The tissue of which they are composed 
 is also not so hard and close in texture, as, if it were 
 so, the bone would be too heavy. There is no finer 
 example of economv of material and the combina- 
 tion of strenofth with liorhtness than the structure 
 of the long bones (Fig. 6). The ends are made of 
 fine threads of bone interlaced and crossing and 
 supporting each other, so as to make a sort of spongy 
 tissue, full of little cavities, and y^X. very strong and 
 
14 
 
 ORGANS OF MOTION, 
 
 tough. And even the shaft of the bone is not solid, 
 butj as every one knows, is hollow in the middle. 
 
 This hollow space and the little 
 cavities of the ends of the bone 
 are filled with what is called 
 marrow^ a substance composed 
 chiefly of blood-vessels and fat, 
 which has important duties to 
 perform in the growth and nour- 
 ishment of the bone. The other 
 varieties of bone are composed 
 entirely of the spongy (or cancel- 
 lous) tissue, with a thin layer of 
 hard, compact tissue on the sur- 
 face. 
 
 i6. The Periosteum and the 
 Minute Structure of Bone. — All 
 the bones are covered with a 
 very tough, strong, fibrous m.em- 
 brane, called tho, perios'teum, ex- 
 cepting at the parts which enter 
 into the formation of the joints, 
 where they are covered with 
 Fig. 6.— The right femur, Cartilage. This membrane ad- 
 or thi-h-bone, sawn in hercs SO closcly to the bonc as to 
 
 two lenslhwise. Notice . ' ^ ^ ^ r r 
 
 the arrangement of the fcquirc Considerable forcc for 
 bony fibers at the upper its Separation. It sccms to f orm 
 
 end, its pecuharity be- ^ -^ ^f ^^iQ boUC. NoW, thc 
 
 ing somewhat exagger- . , , r 
 
 ated so as to make it periostcum and the marrow of 
 
 more plain. the boucs are necessary to their 
 
 growth and nourishment. The 
 
 blood-vessels and nerves spread and divide in these 
 
 tissues before entering the actual substance of the 
 
 bone. The bone itself is full of minute channels and 
 
BONES,— GENERAL STRUCTURE. 
 
 tubes varying in size from ^^ to the -gu-roT of an 
 inch in diameter, through which the blood cir- 
 culates, and the smallest of these tubes are con- 
 nected at one end with exceedingly minute cavi- 
 ties in the bone, in each of which lies a little cell, 
 which does the work of nourishing, repairing, and 
 
 enlarging the bone 
 (Fig. 7). Thus we 
 see that, even in so 
 hard and firm a tis- 
 sue as bone, what 
 has been said about 
 cells holds true. 
 They are the real 
 life of the bone ; 
 they separate from 
 the blood the neces- 
 sary material and 
 deposit it around 
 themselves, some- 
 what as a crab re- 
 news his shell eve- 
 ry year after get- 
 ting rid of the old 
 one. 
 17. Uses of the Periosteum. — It has long been 
 known that, when the periosteum is severely bruised 
 and separated from the bone by violence, the por- 
 tion of bone deprived of the periosteum dies and 
 has to be removed from the bodv. It is also found 
 that a portion of bone, or even an entire bone, may 
 be removed from the bodv, and if it be carefully 
 done, so as to leave the periosteum in its place, the 
 bone will grow again. A remarkable example of 
 
 Fig, 7. — Cross-section of bone, magriified. 
 The small black spots are the caWties ia 
 which the bone-cells live. The fine lines 
 are canals through which the plasma (sec- 
 tion 122) of the blood passes. The large 
 holes are for blood-vessels. 
 
1 6 ORGANS OF MOTION. 
 
 this was a case operated upon by the late Dr. James 
 R. Wood, of New York. In a young woman, whose 
 lower jawbone had become dead and caused her 
 great suffering, this distinguished surgeon removed 
 the whole jaw, leaving the* periosteum and even the 
 teeth, held in their places by an apparatus made for 
 the purpose. The entire bone grew again, and the 
 teeth became fixed in it as it grew. The person 
 died several years afterward, and her skull, show- 
 ing the result of this wonderful operation, is in the 
 museum at Bellevue Hospital."^ 
 
 * Other experiments have even shown that, if a piece of fresh living 
 periosteum be transplanted from a bone to a muscle, it will produce 
 bone in its new situation. These remarkable qualities of the perios- 
 teum have been explained by some, by supposing that, in each case of 
 operation or experiment, some of the minute bone-cells have adhered 
 to the periosteum when the mass of the bone was removed, and that 
 they were the chief agents in forming the new bone. 
 
CHAPTER II. 
 
 NUMBER OF BONES. — PARTICULAR BONES. — JOINTS. 
 
 i8. The number of bones in the human body is 
 two hundred (Fig. 8). At one period of hfe they 
 are nearly all cartilaginous, but the cartilage is grad- 
 ually changed into bone. This process of change, 
 ossification, as it is called, is not complete before the 
 twenty-fifth year of life, and therefore no person 
 can be called really grown up until that time. 
 
 19. The Vertebrse. — The foundation, so to speak, 
 of the body — that portion of the skeleton to which 
 the remainder is attached, and from which it is 
 built up — is the spine, or backbone (Fig. 9). This 
 is composed of many small bones, all of the same 
 general pattern, called vcr'tcbriv. The principal part 
 of the vertebra (Fig. 10), called the body, is shaped 
 very much like a wooden pill-box slightly hollowed 
 out on the top and bottom. The bodies of the ver- 
 tebras form the front of the spinal column. From 
 the rear of each of these bodies are offshoots of 
 bone, which unite in such a way as to leave a hole 
 about half an inch in diameter running up and 
 down. These vertebrae are placed one above an- 
 other, with elastic pads of cartilage between their 
 bodies. These pads are so thick that, taken all to- 
 gether, they make up about one fourth of the whole 
 
i8 
 
 ORGANS OF MOTION. 
 
 Fig. 8.— The skeleton. 
 
THE SPINE. 
 
 lo 
 
 length of the backbone. The vertebrae being ap- 
 phed to each other in this way, it is evident that 
 the holes just mentioned, which 
 are surrounded by bone, w411 form 
 a continuous canal (the spinal ca- 
 nal) running from the skull down 
 the back. This canal contains 
 the spinal cord, which, next to the 
 brain, is the most important part 
 of the nervous system. At the 
 sides of the spine, throughout its 
 whole length, are holes, out of 
 which pass nerves supplying the 
 muscles and other organs of the 
 body, and into which pass the 
 blood-vessels that nourish the 
 spinal cord, 
 
 20. The Spine. — The back- 
 bone, being composed of so many 
 pieces, is very movable. The 
 power of motion varies, however, 
 in different parts. It is greatest 
 in the neck, and least in that por- 
 tion of the back to which the ribs 
 are attached. In the human be- 
 ing, the neck is not so flexible 
 as in many animals. Birds, in 
 particular, can look directly back- 
 ward. 
 
 Notwithstanding 
 
 the 
 
 great 
 
 Fig. 9. — The spine, sa\vn 
 
 in two lengthwise, ^ ... . , 
 
 Showing the spinal powcr of motiou m the spme, the 
 
 canal and the holes different boucs are very strongly 
 
 between the verte- ^^^^-^^^ ^^^^^ protected bv power- 
 
 brae, where nerves and ^ - -^ 
 
 blood-vessels pass out. 
 
 ful ligaments and muscles, which 
 
20 
 
 ORGANS OF MOTION. 
 
 render it difficult for a vertebra to slip out of place, 
 and such an accident is one of the rarest which a 
 surgeon is ever called upon to treat. 
 
 Fig. io. — A vertebra. 
 
 The elastic pads between the vertebrae deaden all 
 shocks of the body and prevent them from injuring 
 the brain. These pads become compressed during 
 the day, especially when a person is much on his 
 feet, so that at night-time the body is from one 
 quarter to one half an inch shorter than it is in the 
 morning. During sleep or rest the elasticity of the 
 pads causes them to resume their original shape 
 and thickness. 
 
 21. The Skull. — The skull is the only portion of 
 the skeleton whose principal office is the protec- 
 tion of soft parts within it. Accordingly, we find 
 
SUTURES OF THE SKULL. 2 1 
 
 that its bones are differently composed and dif- 
 ferently put together from the other bones in the 
 body. Those forming the outside of the skull, im- 
 mediately surrounding the brain, and most exposed 
 to blows, are composed of three layers. The out- 
 side layer is the thickest, and is tough and some- 
 what elastic. The innermost layer is very thin, but 
 hard and brittle, so that it is called the vit'reous 
 (glassy) table of the skull. Between these layers is 
 spongy tissue, like what has been before described. 
 This deadens every blow upon the head, and the 
 safety of the brain is still further provided for by 
 the arched shape of the skull, which tends to dif- 
 fuse the force of a blow. The protection afforded 
 by the shape and structure of the outside por- 
 tion of the skull is very great, and it is a well- 
 known fact in surgery that a blow upon the top 
 of the head, without breaking the bone on which 
 it falls, may break the bones at the base of the 
 skull, immediately opposite the spot of the blow, 
 . by the mere force of the shock, although the latter 
 bones are much thicker and more massive than the 
 others. 
 
 There is only one movable bone in the skull and 
 that is the loivcr jaiv. If the upper jaw be made to 
 move in eating or speaking, it is only by moving 
 the whole head where it joins the neck. 
 
 22. Sutures of the Skull. — The bones of the 
 skull are joined together by what are called sutures 
 — i. e., their edges are jagged and irregular, and fit 
 together like dovetailed boards (Fig. 11). This 
 renders the arch of the skull more compact, and, 
 as far as resistance to pressure is concerned, the 
 V)ones might be considered as one piece, while the 
 3 
 
22 
 
 ORGANS OF MOTION. 
 
 Fig. 
 
 II. — General outlines of the skull, sliow' 
 ing the sutures. 
 
 interruptions at the sutures tend to deaden the 
 shock of a blow. 
 
 23. The Frontal Sinuses. — In the front of the 
 
 skull there are two 
 cavities in the sub- 
 stance of the bone 
 itself. These are 
 situated just above 
 the eye-brows, and 
 are called Xh^ fron- 
 tal si' niLscs (Fig. 1 2). 
 The layer of bone 
 Avhich forms their 
 front wall causes 
 the prominences 
 just over the eye- 
 brows, and, as the cavities increase in size with 
 age, this portion of the forehead becomes more 
 prominent. The cavities are lined with mucous 
 membrane, and are 
 connected with the in- 
 side of the nose by a 
 canal or small passage, 
 so that, when a person 
 has a severe cold in 
 the head, the inflam- 
 mationsometimes runs 
 up this passage into 
 the frontal sinuses. 
 When this is the case, 
 the person has a dull, 
 stuffy headache in that 
 locality, due to the swelling of the mucous membrane. 
 
 24. The Ribs. — The bony part of the walls of 
 
 Fig. 12. — Frontal sinus. 
 
NATURAL SHAPE OF THE CHEST 
 
 23 
 
 the chest is made up of tzventy-four ribs and the 
 breast-bone, together with part of the spine behind. 
 There are twelve ribs on each side, the first, nearest 
 the neck, being usually the shortest. They increase 
 in length from the first to the seventh, and then di« 
 minish, so that the twelfth is also quite short. They 
 are flat and narrow, and are attached at one end to 
 the spine, in such a manner that they move easily 
 up and down, while the other end is attached to the 
 breastbone, or sternum, by means of a piece of car- 
 tilage, varying in length with the length of the rib. 
 The eleventh and twelfth ribs are not attached to 
 anything at their forward end, and hence are called 
 floating ribs. 
 
 The ribs are attached to the spine in such a way 
 that all of them move together up and down. In 
 front, the stiff but elastic cartilage allows motion in 
 every direction. Now the shape of the ribs is so 
 peculiar, being a sort of double curve, that when 
 they are raised at the sides, the ends which join the 
 breastbone are pushed forward, and of course carry 
 the breastbone with them„ So it is evident that at 
 every inspiration the diameter of the chest increases 
 from front to rear as well as from side to side. 
 
 25. Natural Shape of the Chest. — In 3'oung peo- 
 ple the cartilages are soft, but thev grow harder as 
 age advances, and become partially turned into 
 bone. In youth they yield to pressure to such an 
 extent that by tight lacing the shape of the chest is 
 sometimes made exactly the reverse of what it ought 
 to be (Fig. 13). The ribs naturally form a cone, with 
 the smaller end uppermost, but it is not uncom- 
 mon to see the smaller end at the waist. Na- 
 ture will endure a great deal of meddling, but it 
 
24 
 
 ORGANS OF MOTION. 
 
 is not always safe to trifle with her, and all persons 
 who carry tight lacing too far will inevitably suffer. 
 
 26. The Limbs.— More than one half of the 
 bones in the body are found iu the Innbs. Out of two 
 hundred bones, they contain one hundred and twen- 
 ty-six, and these are so constructed and so arranged 
 as to afford a great variety of movement. The up- 
 
THE JOINTS. 
 
 25 
 
 per and lower limbs are what is called Jiomol' ogotis 
 in their parts — i. e., each bone in the arm has its 
 counterpart in the leg, with onh' slight apparent 
 exceptions. Thus, 
 the shoulder-blade 
 corresponds to the 
 body of the hip-bone, 
 the collar-bone to the 
 front of the hip, the 
 arms to the thigh, 
 the two bones of the 
 fore-arm to the two 
 of the leg, the wrist 
 to the ankle, and the 
 hand and fingers to 
 the foot and toes. 
 The similarity and 
 correspondence of 
 these parts are quite 
 clear in the skeleton. 
 27. The Joints. — 
 To render move- 
 ments possible, the 
 skeleton is broken up 
 in its whole extent 
 by numerous joints. 
 The surfaces of the 
 joint are not covered 
 by periosteum, but 
 by a firm, bluish- 
 white, smooth, and 
 very elastic sub- 
 stance called carti- 
 lage. 
 
 pii 
 
 Fig. 14. — The ric;ht knee-joint, sho^^^ng;hov^ 
 strong;ly it is bound about by ligaments. 
 
 The two cartilage-covered surfaces in every 
 
26 ORGANS OF MOTION. 
 
 joint are in contact with each other. The joint is 
 closed entirely by the syno' vial membrane, which 
 passes over from one bone to the other, all round 
 the outside. This membrane is exceedingly smooth 
 and delicate, and its inner surface exudes a fluid very 
 much like the white of an Q^^-, which moistens the 
 surface of the joint and renders every movement 
 easy and frictionless. Outside of these structures 
 are ligaments (Fig-. 14), which hold the bones firmly 
 in their places. Ligaments are composed of white, 
 fibrous tissue (Fig. i) — i. e., of tough, inelastic fibers 
 or threads running parallel with each other, of a 
 shining, silvery-white color. They are flexible, so 
 as to allow of considerable lateral movement, but 
 are tough and exceedingly strong, so that they hold 
 the ends of the bones close together. Thus, the 
 construction of the joints is such that they are 
 strong, flexible, elastic, and supple. 
 
CHAPTER III. 
 
 INJURIES OF BOXES AND JOINTS. 
 
 28. Injuries in General. — The injuries to which 
 the bones are most Hable are fractures and disloca- 
 tions. If the bone be fractured, the jagged ends of 
 the broken bone irritate the parts about them, and 
 the muscles contracting pull the broken ends out of 
 their proper relation to each other (Fig. 15). In the 
 dislocation, the end of the bone is out of its proper 
 place. But the limb is movable at the point of fract- 
 ure, while it is always stiff and fixed at the point 
 of dislocation. In a fracture, also, the ends of the 
 bone, if gently moved against each other, produce 
 a peculiar grating feeling, which always tells the 
 surgeon with certainty that the limb is broken. 
 
 29. Fractures. — Bones are rarely broken straight 
 across, excepting in very young persons. The fract- 
 ure is usually oblique, and so the broken ends slide 
 past each other, and the limb is shorter than it was 
 before the accident. In a broken thigh, the bone is 
 surrounded by such a thick mass of muscles that, 
 even if the broken ends are pulled by force into 
 their proper places, it is impossible to keep them 
 there. They will always slide past each other to a 
 slight extent, and a person never recovers from such 
 an accident, without having the injured limb from 
 
28 
 
 ORGANS OF MOTION, 
 
 DETL 
 
 roiD 
 
 half an inch to an inch shorter than the sound one. 
 
 This has been shown and proved by thousands of 
 
 careful measurements, 
 and should always be 
 borne in mind when 
 there is a temptation to 
 blame a surgeon for fan- 
 cied neglect. 
 
 When a fracture oc- 
 curs near a joint it is a 
 much more serious ac- 
 cident, for the inflam- 
 mation which follows 
 the injury involves the 
 parts about the joint, 
 and sometimes the joint 
 itself, which maybe left 
 stiff and almost useless 
 
 Fig. is.— Fractured humerus, showing f qj- g^ lon^" time aftcr- 
 how the muscles pull the ends of the , ^^^i • • 
 
 broken bone out of place. Ward. This IS particu- 
 
 larly the case with frac- 
 tures near the wrist, for the slow recovery of which 
 the surgeon is so often blamed. 
 
 30. Dislocations. — When a bone is dislocated 
 there is always a certain amount of injury to the 
 parts about the joint. The ends of the bone are so 
 carefully and strongly guarded and fastened by lig- 
 aments and muscles, that these must necessarily be 
 considerably torn and bruised, in order to let the 
 bone out of its place. Thus it happens that a dis- 
 location often gives rise to more pain and suffering 
 immediately after the accident than a fracture.* 
 
 * Sometimes the violence resulting from a fall is not sufficient either 
 to break or dislocate a bone, and yet the parts about a joint are so se- 
 
INJURIES OF BONES AND JOINTS. 29 
 
 The vast majority of dislocations occur in the 
 shoulder and hip joints, and are usually caused by 
 a blow on the end of the bone when the limb is 
 firmly extended, as when a person is falling and tries 
 to save himself by stretching- out his hand. The 
 lower jaw is sometimes dislocated, and then the 
 mouth remains wide open until the dislocation is 
 reduced^ rendering- the sufferer a somewhat ludi- 
 crous as well as pitiable sight. This accident has 
 been known to occur during a prolonged yawn. 
 
 31. Healing of Injured Bones. — A fractured bone 
 takes from three to six weeks, and sometimes longer, 
 to become healed. A dislocated bone, after it is re- 
 duced, requires to be kept quiet until all pain and 
 swelling have subsided. In either case, there always 
 remains more or less stiffness, which sometimes 
 does not disappear for months after the accident. 
 
 Z'2.. Care of Injured Persons. — It frequently hap- 
 pens that a bone is broken when the person is at a 
 distance from his home, or from any place where 
 he can be attended by a surgeon. In fractures of 
 the lower limbs, he must be carried often for a lonsf 
 distance, and every one should know how to make 
 him comfortable during transit. It must be remem- 
 bered that the only object of any person wdio is not 
 a surgeon, should be to keep the broken limb in 
 such a position that there will be no motion of the 
 fractured ends, so that the patient may suffer as 
 little as possible, and the surgeon may find him as 
 nearly as may be in the condition in which the in- 
 
 verely strained that some of the ligaments are torn apart. Very often 
 only a few fibers are ruptured, but such injuries always cause great suf- 
 fering, and recovery is very slow. This form of injury is called a 
 sprain, and is most likely to occur in tlie wri-^t, ankle, or knee. 
 
30 
 
 ORGANS OF MOTION. 
 
 jury left him,* Therefore, he should be carried on 
 a Htter, the broken limb being packed about with 
 soft materials in such a way as to keep it from roll- 
 ing or jarring. The weight of the foot will often 
 make the lower part of the leg swing from side to 
 side, and in the case of a fractured thigh, the leg 
 should be protected on each side from the hip 
 down. Dislocations require the same care, except- 
 ing that a splint is not necessary. 
 
 Z3' Effect of Alcohol on Growing Persons. — 
 Besides the danger connected with the use of alco- 
 holic drinks, which is common to them with other 
 narcotic poisons, alcohol retards the growth of 
 young cells and prevents their proper develop- 
 ment. Now, the bodies of all animals are made up 
 largely of cells, as heretofore shown, 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 alco- 
 hol, in all 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. 
 
 34. Effect of Tobacco on Growing Persons. — 
 Tobacco does not usually produce any permanent 
 changes in the different organs as alcohol does. It 
 seems mainly to influence the functions of organs, 
 
 * It is a very good plan to bind the lower limbs together in such a 
 case, above and below the injured part, so that the sound leg may serve 
 as a splint to the broken one. A broken arm may be bound to an im- 
 provised splint (a cane, a stick of wood, a shingle), a folded handker- 
 chief or other padding being used to fill up the hollows between the 
 splint and the skin, and the broken limb being supported by a sling 
 around the neck. 
 
INJURIES OF BONES AND JOINTS. 31 
 
 without causing their degeneration, and the dys- 
 pepsias and other results of the use of tobacco 
 generally disappear promptly when the cause is 
 removed. This may at least be said of adults, but 
 it is not so true of the young, x-lny prolonged dis- 
 turbance of the normal nutritive processes of the 
 body in a growing person produces permanent re- 
 sults, and children and youth are liable to be stunt- 
 ed physically and mentally by the use of tobacco. 
 The reason for this is plain. Growth and develop- 
 ment go on according to age. They can not be 
 interrupted for months and years and put off until 
 a later period. If the normal development is hin- 
 dered between fourteen and eighteen, and then a 
 healthier mode of life is resumed, the course of 
 development will not be taken up and carried on 
 as if the youth were still fourteen, but the effect of 
 his foolishness will be in great measure permanent. 
 A part of what has been lost mav be recovered if 
 growth has not yet ceased, but it can not all be 
 made up. 
 
 35. Effect of Opium on the Young. — The great 
 difference in the power of resistance between the 
 tissues of the young* and growing person and the 
 adult is strikingly shown by the effect of opium 
 upon them respectively. The danger of giving it 
 to children is so great that medical books are full 
 of cautions against it, and, while one grain is the 
 medicinal dose for an adult and four grains are 
 the smallest quantity known to have been fatal to 
 one, infants have been killed by one twentieth of a 
 grain. 
 
CHAPTER lY, 
 
 MUSCLES. 
 
 36. The Muscles. — The bony framework of the 
 body is set in motion by a system of organs called 
 muscles^ which cover the skeleton almost entirely 
 (Fig. A), and cause the different bones to move 
 upon each other by means of their peculiar prop- 
 erty of contractility, or the power of becoming 
 longer or shorter under varying circumstances. 
 
 There are two kinds of muscles in the body, 
 called voluntary and involinitary, which differ very 
 much in their structure and functions. The volun- 
 tary muscles, as the name implies, are under the con- 
 trol of the will ; while the involuntary muscles are 
 not only beyond our control, but act as a rule with- 
 out our knowledge or consciousness. 
 
 37. The Voluntary Muscles. — A vohtntary muscle 
 is a mass of reddish fibers, somewhat loosely joined 
 together by connective tissue, and easily separated 
 lengthwise.* The fiesh of animals is composed of 
 muscular tissue. Every voluntary muscle is united 
 
 * If the fibers of a piece of lean meat are carefully separated and 
 closely scrutinized, it will be seen that they are connected with each 
 other by a delicate tissue of fine white threads, interwoven like the 
 fibers of a cobweb or of the most delicate lace-work. This is called 
 connective tissue, and is found in almost all parts of the body, uniting 
 the different elements that make up the various organs. 
 
THE MUSCLES. 
 
 33 
 
 Fig. a. — The muscular system. 
 
34 
 
 ORGANS OF MOTION. 
 
 Sit each end to some fixed point in the body, and 
 there is always a joint or point of flexure between 
 its points of attachment. When the muscle con- 
 tracts, therefore, the two ends are brought nearer 
 together, and motion is produced in the organ or 
 limb to which it is attached. 
 
 Every voluntary muscle can be divided into 
 small fibers, lying side by side, and these again into 
 fibrils still more minute. Each fibril under the 
 microscope presents an appearance of delicate lines 
 running at right angles to its length (Fig. i6). 
 
 Fig. i6.— Voluntary muscular tissue. 
 
 These lines are called strict, and the appearance is 
 called striation. 
 
 '^. The Involuntary Muscles. — Invohmtary mus- 
 cles are made up of fiattish bands of long, narrow 
 fibers, tapering at each end, somewhat of the shape 
 of an oat, but more slender. Each fiber has a nu- 
 cleus in its middle, and they are all connected 
 
THE MUSCLES. 
 
 OD 
 
 
 IT:| 
 
 / 
 
 
 ^::, 
 
 together lengthwise, as the voluntary muscular 
 fibers are (Fig. 17). 
 
 39. Differences between the Voluntary and In- 
 t'oluntary Muscles. — The voluntary muscles are all 
 composed of the striated muscular 
 fiber which allows of very rapid 
 contraction, while the involuntary 
 muscular fibers contract in a very 
 peculiar manner. They do not be- 
 gin to contract immediately, as 
 soon as they are stimulated, but 
 there is a short interval between 
 the irritation and the response of 
 the muscle. Then the contraction 
 begins, and proceeds slowly and 
 continuously up to a certain de- 
 gree, when the fibers slowly relax, 
 very much like the slow, crawling 
 motion along the body of a worm 
 or snake, when a wave seems to 
 travel from one end to the other. 
 Now there are some organs in the 
 body, whose action must be rapid, from the nature 
 of the office they perform, and still it would not do 
 to have their motions depend upon the will. Such 
 an organ is the heart. It must contract often and 
 quickly in order to supply sufficient blood to the 
 body, and yet, if its action depended upon our will, 
 it would require all of our attention, to the exclu- 
 sion of everything else. Accordinglv, we find it 
 composed of muscular fibers that are intermediate 
 in structure between the voluntary and involuntary 
 kinds. The involuntary muscular fiber is found, 
 among other places, in the stomach and intestines, 
 
 
 Fig. t7. — Involuntary 
 muscular tissue. 
 
36 ORGANS OF MOTION. 
 
 in the iris of the eye, and in the walls of the ar- 
 teries. 
 
 40. Difference in Size of Muscles. — The largest 
 muscle of the back, the latissimiis dorsi, weighs sev- 
 eral pounds ; and one of the muscles of the leg, the 
 sartor ills, is two feet long ; while \h.Q stapedius, one of 
 the little muscles inside the ear, is only the sixth of 
 an inch long, and weighs about a grain.* Between 
 these extremes are many variations in size and 
 shape. 
 
 41. The Tendons. — Muscles are connected with 
 the bones by means of tendons. A tendon is made 
 up of fibrous tissue, and is a white, glistening cord, 
 of exceeding strength and toughness. At the ends, 
 they gradually change their appearance, becoming 
 muscle at one extremity and bone or periosteum 
 at the other. There is no sharp line, where the 
 muscle or bone can be distinguished from the ten- 
 don. Wherever the tendons would be likely to rise 
 and form a line like the string of a bow during the 
 contraction of a muscle, as at the wrist and the 
 
 * Latis simtis dorsi — i. e., the broadest of the back. This muscle is 
 attached to the spine in the lumbar region and also to the lower ribs. 
 The fibers come together so that the muscle has a triangular shape, and 
 its small end is attached to the humerus. It is the chief muscle that 
 comes in play when the body is raised from the ground by means of the 
 arms. 
 
 The sarto'yius means the tailor's muscle. It is a long, ribbon-like 
 muscle, which begins on the outside of the hip-bone and ends on the 
 inside of the knee, crossing the thigh on the inner side. When it con- 
 tracts, it raises the lower part of the leg, and turns it inward, thus 
 crossing the legs, tailor-fashion — hence its name. It comes in play 
 when one foot is placed on the opposite knee. 
 
 Stapedius means the stirrup-muscle, so-called because it is attached 
 to a small bone in the ear, which is shaped like a stirrup, and hence 
 called stapes (Latin for stirrup). 
 
THE MUSCLES. yj 
 
 ankle, for example, they are bound down by stout 
 ligaments, through or under which they slide to and 
 fro, the channels in which they move being lined 
 with synovial membrane like the joints. 
 
 42. Force of Muscular Contraction. — When a 
 muscle contracts (whether voluntary or involuntary), 
 it becomes not only shorter and thicker, but harder, 
 than before, and the force with which it contracts 
 is enormous. To attain the compactness which w^e 
 see in the body, the muscles of the limbs, for ex- 
 ample, have to lie parallel with the length of the 
 limb. Besides this, many of them are attached be- 
 tw^een the fulcrum and the weight, and very near 
 the fulcrum. The biceps, for instance, which (with 
 the brachialis anticus) bends the forearm upon the 
 arm, is attached at one extremity to the shoulder- 
 blade, and at the other to the forearm, just below 
 the elbow, where its tendon can be felt. Thus there 
 are two disadvantages under which it acts. In the 
 first place, its point of action is only about one eighth 
 as far from the joint or fulcrum as the hand is, and 
 in the second place, when it begins to contract, it 
 acts at a very acute angle — in fact, almost parallel 
 with the bone (Fig. 18). As the arm becomes flexed, 
 
 Fig. 18. — Disadvantageous action of the biceps muscle, 
 illustrated. 
 
 the angle of action approaches more and more to a 
 right angle, and the necessary effort becomes Isss 
 4 
 
38 ORGANS OF MOTION, 
 
 and less. And yet we not only flex the arm easily 
 enough at the elbow, but we do it with a consider- 
 able weight in the hand. It has been estimated that 
 the muscles of the arm, in flexing it at the elbow, 
 with a ten-pound weight in the hand, contract with 
 a force of at least two hundred pounds. And yet 
 this is a feat which a delicate woman or a child can 
 perform, and the force required is not to be com- 
 pared with the power of an athlete. 
 
 43- Muscular Irritability. — Muscular tissue will 
 contract under any kind of irritation. In the living 
 body, the stimulus always comes from the nerves, 
 but the muscle itself has a form of irritability, which 
 lasts for a considerable time after death. When an 
 ox is killed, and has been prepared for the market, 
 the muscles may often be seen twitching and quiver- 
 ing in the beef for half an hour, and the muscles of 
 an amputated arm may also be seen to contract for 
 some minutes merely under the irritation of the cold 
 air. In cold-blooded animals, this irritability persists 
 for a long time. If the heart of a frog be entirely 
 removed from the body, it will continue to beat for 
 several minutes, and, when it has finally ceased, it 
 will start again on being pricked with a needle. 
 This experiment may be repeated several times be- 
 fore the muscular irritability finally vanishes.'^ 
 
 44. The Muscular Sense. — When a muscle con- 
 tracts, the degree of contraction is perceived or felt 
 
 * There are reasons for believing that the continued beating of the 
 heart of a cold-blooded animal for hours after it has been removed 
 from the body may be due to the presence of microscopic nervous 
 ganglia in the substance of the muscle. This supposition, however, 
 does not affect the usefulness of the frog's heart as an illustration of 
 the fact that parts of animals continue to live after separation from the 
 main body. 
 
THE MUSCLES. 39 
 
 by the brain. For example, any one is conscious 
 whether his thumb is bent inward toward the hand, 
 or outward toward the wrist, entirely apart from 
 the use of the sight. The precise manner in which 
 this sensation is conveyed to the brain is still a sub- 
 ject of conjecture. Although apparently so simple, 
 it brings up questions of great intricacy and dif- 
 ficulty, which can not be considered here. But this 
 sense, whatever its manner of operation, is called the 
 muscular sense. It is one of the chief means we have 
 of determining the weight or the hardness and soft- 
 ness of bodies, as w^e judge of these qualities mainly 
 by the resistance our muscles meet with when hand- 
 ling the bodies. But, more than all, the muscular 
 sense is necessary in keeping the body upright. The 
 size of the feet is so small, compared with the height 
 of the body, that early in life it is a matter of ex- 
 treme difficulty for us to keep our balance. To 
 stand and walk is one of the first and one of the 
 hardest things we have to learn. It requires a con- 
 stant contraction of the muscles, now one set and 
 now another, in order to keep from falling. 
 
 45. Use of the Muscular Sense in Standing. — 
 Ordinarily we are assisted in standing upright b}' our 
 sight. This fact, together with the muscular effort 
 required to stand still, may both be made very evi- 
 dent in the following manner : if a person stands 
 with the feet close together, he will perhaps feci a 
 slight swaying of the body, which has to be counter- 
 acted by muscular contraction. Perhaps no such 
 swaying will be perceptible to him. But now, still 
 keeping the feet close together, let him shut the 
 eyes, when the swaying of the body will become 
 much greater than before, and the constant muscular 
 
40 ORGANS OF MOTION. 
 
 contractions, now here, now there, will be so plainly 
 felt as to be disagreeable. In certain diseases, this 
 muscular sense in the legs is lost, and then the per- 
 son can stand with the eyes open, but if the eyes be 
 closed he instantly totters and falls, for he then has 
 nothing to guide him as to his vertical position. 
 
 46. Waste during Muscular Contraction. — The 
 cause of muscular contraction is an unsolved prob- 
 lem. There is nothing in the chemical composition 
 or the physical structure of the muscle which would 
 lead us to expect to see it contract when irritated, 
 if we knew nothing more about it. All we can say 
 is, that it depends upon the composition of the mus- 
 cular substance, and we know, also, that every con- 
 traction is accompanied by a loss of or change of 
 material. In this Avay, our muscles are being con- 
 tinually used up, and if they were not constantly sup- 
 plied with fresh nourishment by the blood, they 
 would soon wear out and die. But the minute mus- 
 cular fibers (or the cells composing them) not only 
 perform their special function of contraction, but 
 are able to choose and take up out of the blood their 
 own proper food and appropriate it. 
 
 47. Muscular Overwork. — If a muscle is hard 
 pressed and exercised too much, so that the waste 
 of material is greater than the supply, and it wears 
 away faster than it is repaired, it falls into the con- 
 dition which we call fatigue, and it is only with 
 great effort that w^e can make it work. If it be still 
 further imposed on, without opportunity to recu- 
 perate, it soon gives out entirely, and can not be 
 made to contract with vigor under any stimulus our 
 brain can send to it. Such extreme fatigue is dan- 
 gerous, because there is always the chance that the 
 
THE MUSCLES. 41 
 
 muscular fibers may become so completely wasted 
 that even their power of nourishing themselves may 
 be impaired, and the recovery of their natural con- 
 dition may be very slow and imperfect, or, in rare 
 cases, impossible. 
 
 48. Muscular Inactivity. — On the other hand, if a 
 muscle is not exercised at all, its power of nourish- 
 in": itself is interfered with almost as much as if it is 
 exercised too much. It is found that unused mus- 
 cles gradually waste away, growing smaller and 
 smaller, and becoming soft and flabby, and finally, if 
 they are not used for a ver}^ long time, it can be seen 
 by the microscope that the muscular fibers disappear 
 altogether, or are filled with little particles of fat, 
 which take the place of some of the muscular sub- 
 stance, and so make it very weak and useless. Such 
 inactivity of the muscles may occur in cases of paral- 
 ysis, and the physician is then careful to stimulate 
 them with electricity, in order to keep them, as 
 nearly as possible, in a sound condition. The elec- 
 trical current, in such cases, takes the place of the 
 nervous stimulus, which naturallv causes muscular 
 contraction. The muscles of a broken limb, also, 
 which have necessarily been idle while the bone was 
 mending, are always ver}^ feeble for some time after 
 the limb comes in use again.* 
 
 * Curvature of the spine, which is more frequent among girls than 
 among boys, is often directly attributable to lack of exercise. The 
 muscles of the back become weak, and, as some exercise of the muscles 
 of the right side can not be avoided, so long as the girl performs any 
 duties whatever, the difference in strength between the muscles of the 
 right side and those of the left side becomes greater than is natural. 
 The result of this is that the stronger muscles ovei-power the others and 
 pull the spine over toward the right side, greatly distorting the figure. 
 In left-handed persons the cui-vature is toward the left side. 
 
42 ORGANS OF MOTION. 
 
 49. ExercisCo — It is necessary, therefore, that the 
 muscles should be sufficiently exercised, and not too 
 much. The kind of exercise is not of so much im- 
 portance. No better form of exercise can be de- 
 vised than the various out-door sports that boys are 
 so fond ofo It is much better that exercise should 
 be a pleasure than a duty. For this reason, the or- 
 dinary exercises of the gymnasium do not compare 
 in value, as health-giving ones, with rowing, skating, 
 running, riding, wrestling, swimming, and the va- 
 rious out-door games.^ It is really of no 'advantage, 
 in our ordinary modern life, that the upper arm 
 should, by judiciously and ingeniously planned ex- 
 ercise, grow to be an inch larger than it was a year 
 before, and to the ordinary youth the duties of a 
 gymnasium are irksome to the last degree. f There 
 is no evidence that athletes, whose bodies are 
 knobbed with unsightly bunches of muscle, are any 
 healthier or any happier, or live any longer, or do 
 any more good in the world, than the less muscular 
 
 * These remarks apply to girls as well as to boys. Out-door exer- 
 cise of an agreeable kind is as necessary for the health of one as of the 
 other. The hot-house plant is never strong, and the tom-boy grows to 
 be the most healthy and vigorous woman, both mentally and physically. 
 
 f It is not to be understood that the g)'mnasium is here altogether 
 condemned. It is of great use in its proper sphere. But the boy's idea 
 of a gymnasium is that it is a place to get strong, rather than healthy. 
 The surroundings and examples are such as to encourage straining for 
 effect, lifting heavy weights in emulation, and the like acts, which may 
 injure a boy permanently. When gymnastic exercises are performed 
 under a competent instructor, with proper ends in view, and an intelli- 
 gent use of means to those ends, the matter is altogether different. 
 But, as mentioned in the text, gymnastic exercises, excepting for the 
 purpose of remedying particular defects, training special muscles for a 
 particular purpose, or treating actual disease, can not be compared in 
 efficiency with out-door sports. 
 
EXERCISE. 43 
 
 person who coniines himself to simple food, who in- 
 sists upon pure air, and exercises moderately and for 
 his own pleasure in the way that suits him best.* 
 
 50. Danger of Exhaustion. — But, w hile muscular 
 exercise is necessary to continued good health, it 
 should never be carried to the point of exhaustion. 
 This is dangerous, not only, as previously indicated, 
 because the nutrition of the muscle may thus be in- 
 terfered with, but because, when the point of simple 
 fatigue is passed, and exhaustion supervenes, the 
 nervous system has become implicated and is getting 
 worn out. This danger will be better understood 
 when that part of our bodies is described hereafter. 
 It is enough, for the present, to remember that a 
 person is not harmed by being tired, but that it ahvays 
 harms one to be exhausted. 
 
 51. Rest. — When a muscle is fatigued, it recov- 
 ers very fast if allowed to rest. For this reason 
 it is much less fatiguing to walk an hour than to 
 
 * The muscular strength which is developed by gyninastic training 
 vanishes when the training ceases. It is often noticed by those who 
 practice much in gymnasiums that constant practice is necessary to re- 
 tain what increase of muscular power they have acquired. There seems 
 to be a normal condition of the muscular system in each individual, to 
 which he reverts when special training is abandoned. The strong men 
 are not made so by training ; they are born with a tendency to a pre- 
 ponderance of the muscular organs. Marvelous stories are told of 
 men of this class. It is said of Frederick Augustus of Saxony, King 
 of Poland (1670-1733), commonly called Augustus the Strong, that on 
 one occasion, wishing to present a bouquet to a lady, and seeing nothing 
 to wrap it in, he took a silver plate from the table and folded it around 
 the stems wilh the greatest ease. In Dresden is exhibited a horseshoe, 
 or the halves of it, which he is said to have broken with one hand. 
 Similar stories are told of Baron Trenck (1711-1747) ; and of Milo, of 
 Crotona, a famous athlete (520 B. c), it is said that he once carried a 
 live ox on his shoulders around the stadium, then killed it with a blow 
 of his fist, and afterward ate the whole of it in a single day. 
 
44 ORGANS OF MOTION. 
 
 stand still an hour. In the former case the muscles 
 constantly have short intervals of rest, while in the 
 latter they are not able to rest at all, but are con- 
 tinually in a state of contraction. If we are obliged 
 to stand for a long time, therefore, we almost in- 
 stinctively change our position frequently, stand on 
 one leg and then on the other, or find some place 
 to lean against, in order to give the muscles the 
 rest they need. 
 
 Out-door sports^ then, are more healthful than gym- 
 nastic exercises. 
 
 Exercise may be pushed to the point of fatigue with- 
 out injury, but never to the point of exhaustion. 
 
 52. General Effects of Alcohol upon the Struct- 
 ures of the Body. — When alcohol is introduced 
 into the system it circulates in the blood, and, 
 coming directly in contact with the different or- 
 gans, irritates the delicate structures of which they 
 are composed ; and, if used habitually, tends to pro- 
 duce gradual permanent changes in them, which 
 can mostly be brought under two heads, viz., an 
 increase of connective tissue or a deposit of fat. 
 Both of these tissues in the healthy body are chiefly 
 useful on account of their physical properties, the 
 connective tissue serving as a closely woven web or 
 frame-work to support the softer structures (cells, 
 etc.) and retain them in position, while the fat 
 makes up the padding of the body, and also forms 
 a reserve fund upon which the working tissues 
 draw for sustenance when the amount of food taken 
 is insufficient. When these tissues are deposited in 
 abnormal quantities, however, they become great 
 agents of harm. They encroach upon the neigh- 
 boring cells, squeeze them out of shape, interfere 
 
EXERCISE. 
 
 45 
 
 with their nutrition and the proper performance of 
 their functions, and so diminish secretion and ex- 
 cretion, press upon and obstruct, or even obliterate, 
 blood-vessels, irritate nerves, and in many other 
 ways throw the delicate mechanism of the body 
 out of gear. These alterations will be more par- 
 ticularly mentioned hereafter. 
 
 53. Effect of Alcohol upon the Muscles. — Fatty 
 degeneration of the muscle is a common result of 
 the use of alcoholic drinks, especially beer. 
 
 The microscope shows a striking difference be- 
 tween the firm, elastic structure of a healthy man's 
 muscle and the pale, flabby, inelastic fibers of a 
 heavy, inactive beer-drinker. Such a person may 
 appear very strong and healthy, but his strength 
 quickly deserts him upon any unusual exertion. It 
 is found, also, that even moderate drinkers are more 
 likely to be attacked by epidemic diseases, that they 
 do not bear surgical operations so well, that they 
 suffer more from exposure of any kind, and that 
 they are apt to succumb to diseases from which the 
 abstinent generally recover. 
 
 54. Alcohol diminishes the Power of Endurance. 
 ^It has been amply shown by Arctic exploration 
 and by military campaigns in India and Africa, 
 that those who use no alcohol endure privation, 
 fatiguing labor, and extremes of temperature much 
 better than those who take dailv rations of grog. 
 The common opinion that alcoholic liquors ward off 
 the cold and temper the heat arises from the fact 
 that the bodily sensations are dulled by the narcotic ; 
 the drinker, in other words, is partially ancesthe- 
 tized, so that, although he feels cold and heat in a 
 less degree, he is really less able to resist them. 
 
PART III. 
 
 ORGANS OF REPAIR. 
 
 CHAPTER I. 
 
 FOOD. 
 
 55. Necessity of Food. — We all know that, as 
 long as we are living beings, we tend constantly to 
 lose weight. In our excretions, our breath, the per- 
 spiration, the tears, the saliva, we lose altogether 
 several pounds a day. All of this matter is so much 
 gone, and if it be not replaced the body dies. It 
 can not be too clearly impressed upon the mind 
 that this v/aste or loss of material is continuous 
 and inevitable. The processes of muscular contrac- 
 tion, of secretion, even of thought, produce sub- 
 stances which are taken up by the blood to be put 
 out of the body. These substances are, many of 
 them, very poisonous, and if they can not be ex- 
 pelled from the body they kill it.^' They are not 
 the result of disease ; they are the constant product 
 of living processes in a healthy body. So we see 
 
 * Thus certain waste matters are excreted from the body through 
 the kidneys. Some of them are very poisonous, and, when the kidneys 
 are diseased and are no longer able to discharge them all from the body, 
 they accumulate in the blood and finally cause death. So it is with the 
 bile and with certain matters which pass away in the breath at every 
 respiration. 
 
FOOD. 47 
 
 that there must be a continuous expulsion of such 
 matters, and, of course, what each part of the body 
 has lost by such a process must be replaced with 
 fresh material. 
 
 56. Living without Food impossible. — If this fact 
 be clearly understood, it will be easy to see that the 
 numerous stories about persons who live without 
 eating are false. If such persons live, their hearts 
 must beat, their brains must think, their lungs must 
 move in breathing, and all of these things cause in- 
 evitably a waste of material. How absurd, then, to 
 gravely talk of a person who has not taken any 
 food or drink for six months, and still has not lost 
 weight, but remains plump and healthy I It is just 
 as absurd as it would be to say that such or such a 
 person had a limb amputated day after day, and yet 
 after each operation weighed as much as before. 
 These cases are all cheats, for if there is waste sfoins: 
 on, which is not made good, the body must decrease 
 in weight. If there is no waste, there is no life, no 
 thought, no heart-beats, no respiration, no move- 
 ment of any kind. These facts of the generation of 
 force by food and of constant loss and gain are the 
 chief foundation-stones of all correct knowledge of 
 physiology, and can not be too firmly fixed in the 
 mind. 
 
 57. Classification of Food. — In order to supplv 
 the waste in our bodies we need a great variety of 
 tood ; and, indeed, the procuring and preparing of 
 food occupy a large portion of the lives of most peo- 
 ple. The food we use is usually classified as nitroge- 
 nous and non-7iitrogenoiiSy or carbonaceous. But, besides 
 these two great divisions, which include all our ani- 
 mal and vegetable food, there are some substances 
 
48 ORGANS OF REPAIR. 
 
 which are neither animal nor vegetable, and yet are 
 quite as necessary to our health as any other por- 
 tion of what we eat. The most important of these 
 are water and salt. 
 
 58. Water. — Water is present in a greater or less 
 quantity in every part of the body, and, as it is rap- 
 idly expelled, it has to be frequently supplied. It 
 constitutes between three fourths and two thirds of 
 the entire weight of the body, and the amount re- 
 quired for an adult man daily is about three pints, 
 in addition to that which forms a part of the solid 
 food. The quantity used varies enormously, accord- 
 ing to the waste. In a hot day in summer we need 
 much more than in cold weather, and in damp days 
 much less than on dry ones. 
 
 59. Salt. — Salt, also, is not only an agreeable con- 
 diment, but has important offices to perform in the 
 body. It has been shown by experiments on ani- 
 mals that, if they are entirely deprived of salt, they 
 decline very much in vigor, and every farmer knows 
 how necessary it is to the health of his cattle and 
 sheep.* 
 
 60. Other Inorganic Matters. — There are other 
 
 * Boussingault, a Frencli chemist (bom in 1802), reported in 1854 
 some experiments he had made in regard to the importance of salt to 
 cattle. He took six bullocks, of about the same age and vigor, and fed 
 them alike, excepting that to three of them he gave 500 grains of salt 
 every day and to the others none. At the end of six months the hides 
 of those that had had no salt were rough and dull in color, while those 
 of the others were shining and smooth. At the end of a year the salt- 
 fed bullocks were in perfect health, while the others were dull and 
 stupid, and the hair upon their hides was rough and tangled, with bare 
 patches here and there. 
 
 Wild animals, especially of the grazing kind, like deer and cattle, 
 will travel long distances in search of salt, and seem to be as fond of 
 it as children are of sugar. 
 
FOOD. 
 
 49 
 
 inorganic matters which are essential to the growth 
 and nutrition of the body, but which are naturally 
 found in articles of food and are not taken sepa- 
 rately. Such are the salts of liuie, soda, potash, and 
 viagncsia, all of which form a part of our common 
 fruits and vegetables. The most important of these 
 is probably the lime phosphate which forms so great 
 a part of the bones. The husk of grain contains a 
 certain proportion of this salt, and in growing chil- 
 dren, in whom the cartilaginous portions of the 
 bones are becoming ossified, wheaten grits or Gra- 
 ham bread is a very welcome and advantageous ar- 
 ticle of diet. It has been affirmed that the large size 
 of the inhabitants of Kentuck}^ is due to the fact that 
 they live in a limestone region, and the water they 
 use is strongly impregnated with lime. So large a 
 proportion of lime taken into the body, at a time 
 when the bones are forming and growing and hard- 
 ening, is said to make them longer and stronger 
 than they would be otherwise. 
 
 6i. Non-nitrogenous Foods. — The non-nitroge- 
 noiis, or, as they are sometimes called, the earbonaceoiis 
 foods, are sugar, stareJi, and fat. These substances 
 are all composed of carbon, h^^drogen, and oxygen, 
 in varying proportions, the sugar and starch taken 
 in our food being mostly of vegetable origin, while 
 the fat mav be either animal or vegetable. 
 
 62. Starch. — Starch forms a part of all grains and 
 most vegetables, sago, tapioca, arrowroot, etc., be- 
 ing almost pure starch, which has been extracted 
 from the plants in which it is found. Rice contains 
 about 85 per cent of starch, wheat about 70 per 
 cent, and the potato about 15 per cent. This latter 
 amount seems very small, but most of the remainder 
 
50 ORGANS OF REPAIR. 
 
 of the lOO parts of the potato consist of water, and 
 starch really forms the bulk of the solid matter. 
 
 It is a peculiarity of starch that it is very easily 
 converted into sugar. This is actually accomplished 
 in the human body, during the processes of masti- 
 cation and digestion, as will be shown hereafter. 
 
 63. Sugar. — Sugar is taken in our food in various 
 forms, for it has not always the same chemical com- 
 position. It is always sweet, and is always easy to 
 recognize as sugar, but varies in its proportions of 
 carbon, hydrogen, and oxygen. Thus we find that 
 cane-sugar, milk-sugar, and grape- or honey-sugar 
 (often called glucose ^), all differ from each other. 
 Sugar is taken partly as an addition to the food for 
 the sake of improving its flavor, and partly as a nat- 
 ural constituent of vegetables and particularly of 
 fruits, some of which contain an enormous propor- 
 tion of it. Figs, for example, are more than half 
 sugar, and hardly any fruit contains less than 10 per 
 cent, 
 
 64. Fat. — Fat is found in almost all parts of the 
 body, and particularly just underneath the skin, 
 where it serves to give rounded outhnes to the form, 
 and also undoubtedly acts as an elastic cushion to 
 protect the parts beneath from injury. During life, 
 owing to the warmth of the body, the fat is fluid and 
 transparent ; f but after death, as the body cools, it 
 
 * Glucose is now produced artificially in enormous quantities by the 
 use of sulphuric acid and corn. When anything containing starch is 
 boiled with this acid, the starch is converted into glucose, which is the 
 kind of sugar found in fruits. Cane-sugar can be changed into glucose 
 in the same way, and as a matter of fact it is changed into glucose in 
 the act of digestion, so that glucose must be looked upon as that form 
 of sugar that it is natural for us to take in our food. 
 
 f If the fingers be held close together in front of a bright light, the 
 
FOOD. 
 
 51 
 
 becomes solid. The fat which is found in the body 
 is not all taken in with the food, but a certain amount 
 of it is formed in the body itself, in a manner which 
 is not yet understood. Certain articles of diet tend 
 to increase the amount of fat in the body. This is 
 notably the case with starch and susrar. In susfar- 
 growing- countries, as the Southern States, it is a 
 matter of common observation that the field hands 
 grow fat and sleek during the sugar-season, and lose 
 their superabundant flesh when the season is over. 
 Articles of food which contain much starch also in- 
 crease the amount of fat. The famous Banting sj'S- 
 tem of treating corpulence is based on this fact, and 
 consists mainl}' in depriving the patient of starchy 
 vegetables, grains, and sugar."- 
 
 65. Nitrogenous Foods. — The nitrogenous por- 
 tion of our food is also both animal and vegetable, 
 but chiefly animal. The principal substances of 
 this class are fi'briu, albit'incn, and ca'sc'in. They 
 all contain a considerable amount of nitrogen, in 
 addition to carbon, hydrogen, and oxygen, and are 
 generally called by physiologists pro' tad substances, 
 or the proteids. 
 
 Casein is found in large proportion in milk, from 
 which it is extracted to form cheese, and the two 
 
 rosy tinge of their borders shows that they are to a certain extent 
 translucent. The fingers of a corpse, under similar conditions, are 
 opaque. 
 
 * Mr. Banting, the court undertaker, was put under treatment for 
 corpulence by Mr. William Harvey, a London surgeon. He was al- 
 lowed to eat any meat except pork, any kind of fish except salmon or 
 eels, any vegetables except potatoes or rice, any kind of poultry or 
 game, dry toast, fresh fruit, and tea without milk or sugar. When he 
 began this diet in August, 1862, he weighed two hundred and two 
 pounds, and a year after, he had lost forty-six pounds, and reduced 
 his girth twelve and a quarter inches. 
 
52 
 
 ORGANS OF REPAIR. 
 
 others are found mostly in the animal fluids, and in 
 muscular fiber. 
 
 There are also substances very much like the 
 animal albumen and casein which are found in vege- 
 tables, but they present slight chemical differences, 
 although they probably answer nearly the same 
 purpose in nutrition. Peas and beans contain a con- 
 siderable quantity of the vegetable casein. 
 
 td. Necessity of Variety of Food. — It is neces- 
 sary, for the preservation of health, that our food 
 should contain a sufficient amount of these different 
 kinds of matter. We must have water ; we must 
 have salt and the lime compounds mentioned above ; 
 we must have starchy substances (much the same to 
 the body as sugar) and fats,^ and we must have a 
 certain amount of nitrogenous food. If one of these 
 be lacking, the body soon feels it, and, although the 
 person may not know precisely why he feels bad, 
 he will often recover from his temporary disorder 
 by a mere change of diet. The lack of any particu- 
 lar ingredient in our food is often indicated to us by 
 a longing for it. We feel a strong desire to eat par- 
 ticular things and no others, and such a desire may 
 generally be taken as a safe indication that the body 
 needs them. 
 
 67. Paramount Necessity of Water. — Of all arti- 
 cles used for food or drink, water, in some form 
 or other, is the most indispensable. Men can live 
 much longer on water without food than on food 
 without water. The celebrated French physiolo- 
 gist, Magendie, found that dogs lived eight or ten 
 
 * This is said of a healthy person. Excessive production of fat, as 
 in Mr. Banting's case, is to be regarded as a diseased condition, and so 
 requires special diet» 
 
FOOD. 53 
 
 days longer, when supplied with water alone, than 
 when they were deprived of both food and water. 
 The pangs of thirst have been felt in a slight de- 
 gree by almost every one, and it is the experience 
 of those wdio have suffered from deprivation of 
 food and w^ater, in deserts and shipwrecks, that the 
 tortures of thirst are much harder to bear than 
 those of hunger. 
 
 68. Daily Amount of Food. — It has been found 
 by Dr. Dalton, by experiments upon himself, that 
 an adult requires food in about the following pro- 
 portions : 
 
 Meat 1 6 ounces. 
 
 Bread 19 '' 
 
 Butter, or fat i\ " 
 
 Water 52 " 
 
 or about two pounds and a half of solid food and 
 about three pints of liquid food daily. This is 
 about the least amount which will keep him in 
 good health. 
 
 69. Cooking. — Man does not take his food m 
 the natural state, like other animals, but prepares 
 it by cooking. This process is of advantage in two 
 ways: it softens the hard parts of the food, such 
 as beans, potatoes, and the various grains, and the 
 fibrous tissue of meat ; and it also develops a pleas- 
 ant flavor by the action of heat, which excites the 
 flow of the fluids of the mouth and stomach, and 
 thus aids digestion. 
 
CHAPTER II. 
 
 ORIGIN AND NATURE OF ALCOHOLIC DRINKS. 
 
 70. Fermentation. — For many ages men have 
 prepared certain intoxicating beverages without 
 knowing their real nature, which has only been 
 understood within the last thirty years. It is now 
 known that these beverages are the result of the 
 same general law of Nature that causes our bread 
 to mold, our preserves to sour, and makes other 
 articles of food unfit to eat. 
 
 When living matter ceases to live, its compo- 
 nent parts are gradually decomposed or dissociated 
 from each other, and form new combinations. The 
 tree decays, the fruit rots, animal matter putrefies, 
 and thus the surface of the earth is kept clear from 
 an accumulation of lifeless matter that would pre- 
 vent new growth. ''One grand phenomenon," says 
 M. Pasteur, " presides over this vast work — the 
 phenomenon of fermentation." The process by 
 which this work is accomplished is believed to be 
 due to the presence of small living bodies, or micro- 
 organisms. In appropriating from the substances 
 they work upon the elements necessary for their 
 own support, these micro-organisms give rise to 
 new compounds, many of which are poisonous. 
 They pervade Nature almost everywhere; the air 
 
NATURE OF ALCOHOLIC DRINL<S. 55 
 
 is full of them. Vigorous living matter they are 
 powerless to affect ; but on dead matter their work 
 begins. 
 
 71. Nature of Fermentation. — There are many 
 kinds of fermentation, each having its own special 
 micro-organism, and each micro-organism produc- 
 ing its own special result. That which takes place 
 in proteids, giving rise to offensive odors, is usually 
 called "putrefactive fermentation"; but the kind 
 which results in the various intoxicating beverages 
 just referred to is called '' vinous fermentation." 
 
 The micro-organisms, or ferments of vinous fer- 
 mentation, appear under the microscope as bead- 
 like cells. Under the right conditions, in a liquid 
 containing sugar, they grow and multipl}^ rapidly 
 by a process called budding. They act upon the 
 sugar of the liquid, causing it to break up into two 
 new substances, carbon dioxide, usually called car- 
 bonic-acid gas, and alcohol. 
 
 Neither of these substances is at all like the 
 sugar from which it has been produced. It is a law 
 of Nature that fermentation changes the character 
 of a substance it works upon.- The carbon dioxide 
 is a gas which passes rapidly out of the liquor.f 
 
 * Vinegar, a substance entire!}' different from wine or cider, is pro- 
 cured from these liquors by a fermentation called " acetous feiTnenta- 
 tion." This is brought about by the action of micro-organisms called 
 " mycoderma aceti," which belong to a different family from those of 
 vinous fermentation. During acetous fermentation the alcohol disap- 
 pears, and acetic acid, the sour principle of vinegar, takes its place. 
 Vinegar contains no alcohol. 
 
 f Carbon dioxide is the gas which imparts the eflfervescent quality 
 to all drinks. It is freely soluble in cold water, more so under press- 
 ure, and when the liquid is relieved of pressure, as when soda-water is 
 drawn from a fountain, or as the liquid becomes warmer, the gas is 
 freed and escapes from it in bubbles. When any liquid containing 
 
56 ORGANS OF REPAIR. 
 
 The alcohol is a liquid, and does not pass out of 
 the fermenting fiuid. It is a poison, and imparts 
 its poisonous quality to any liquid containing it. 
 It primarily affects the brain, and is therefore 
 classed as a cerebral, or narcotic poison. Before 
 the nature of alcohol was well understood it was 
 considered a food ; but we now know that it does 
 not repair the waste of tissues as vegetables, meats, 
 fruits, and other articles of food do. It contains no 
 nitrogen, which is an essential element in nearly 
 every tissue of the body, and it can not therefore 
 be considered nutriment. 
 
 72. The various alcoholic beverages are mostly 
 manufactured from two kinds of vegetable products, 
 viz., the malt liquors from grain, the wines from 
 fruits, and the distilled liquors from either. The 
 process differs somewhat according to the material 
 used, because fruits naturally contain sugar, while 
 grains do not, and the brewer or distiller has to 
 procure the sugar first. 
 
 73. Manufacture of Malt Liquors. — To manu- 
 facture malt liquors, the grain (generally barley, 
 but often wheat, rice, or corn) is soaked with water 
 until it is soft and swollen, and then piled in heaps 
 in a warm atmosphere until it begins to sprout. 
 This process (which takes place naturally in the 
 ground when the seed is planted) changes a por- 
 tion of the gluten into a substance called diastase, 
 and this, in some way not yet clearly understood, 
 
 carbon dioxide is discharged into a glass, the bubbles of gas rise con- 
 stantly from the sides and bottom, because the outside of the glass is 
 constantly absorbing heat, and as warm water does not retain it in 
 solution, it is constantly escaping from the warmest part of the liquid 
 and rising to the surface. 
 
NATURE OF ALCOHOLIC DRINKS. 57 
 
 converts the starch, which constitutes the greater 
 part of the grain into a kind of sugar {maltose),'^ This 
 sugar would naturally be appropriated as nourish- 
 ment by the growing plant, but before that can oc- 
 cur the sprouting grains are dried and charred in a 
 hot kiln, forming what is known as i/ialt. The heat 
 kills the germ, but the sugar remains. The malt is 
 then crushed and mixed with water in huge vats, 
 where the sugar is dissolved out of it, as well as 
 various other matters which impart color and flavor 
 to the liquid. The liquid thus obtained, called the 
 wort, is then drawn off and boiled with hops, both 
 for the purpose of imparting a desired bitter flavor 
 to the beer, and also of preventing germs from 
 developing within it. This new decoction is then 
 plied with yeast (consisting almost entirely of the 
 micro-organisms of vinous fermentation), which be- 
 gin at once to decompose the sugar of the liquid. 
 When their work has proceeded far enough for the 
 purpose of the brewer, the liquor is drawn off into 
 closed casks, and kept in a cool place until used. 
 
 74. Malt Beverages. — The beverages produced 
 in this way are ale, lager-beer, weiss-beer, porter, 
 and stout. Ale, porter, and stout have the largest 
 portion of alcohol, as the process of fermentation 
 is allowed to go further before they are used as 
 beverages. Porter and stout owe their dark color 
 to the greater charring of the grain, producing 
 caramel, or burned sugar, in the malt. These liq- 
 uors contain from four to ten per cent of alcohoL 
 Lager-beer, as sold in this country (really schenk- 
 
 * This process is known as " saccharine fermentation," but is not 
 believed to be due to the action of an organized ferment, such as the 
 micro-oi"ganisms of putrefactive and vinous fermentation. 
 
58 ORGANS OF REPAIR. 
 
 bier), generally contains from two and a half to^five 
 per cent, and weiss-beer about two per cent. 
 
 75» The Alcoholic Appetite. — It must be re- 
 membered that in whatever quantity, or wherever 
 alcohol is found, its nature is the same. It is not 
 only a poison, but a narcotic poison. It belongs to 
 the same class with opium, chloroform, ether, hy- 
 drate of choral, etc. ; one great peculiarity of which 
 is that they never leave the body through which 
 they have once passed in quite the same condition 
 in which they found it. The person who has once 
 taken them is apt to feel a desire to take them 
 again. And this desire is not like the ordinary 
 appetite for food. It is not that their smell or 
 taste is agreeable, for the reverse is often the case. 
 It is the after-effect that is sought. The oftener 
 this desire is gratified, the more imperious it be- 
 comes, until finally the man is no longer master of 
 himself ; he neglects his daily affairs, and takes no 
 interest in anybody or anything but plans for a 
 fresh supply of the poison. The alcohol found in 
 beer and other light liquors, though present only 
 in small quantities, possesses this cumulative attrac- 
 tion for itself, which tends, sooner or later, to lead 
 to excess. The craving for alcohol, when indulged, 
 becomes a disease both of body and mind. The 
 only remedy for the disease is to remove the cause, 
 by adhering strictly to total abstinence. Such ab- 
 stinence is also the only absolute safeguard against 
 forming this unnatural craving. In view of this 
 easily formed and more easily aroused appetite, the 
 custom of flavoring food of any kind with any 
 formx of alcohol is a dangerous one that should be 
 avoided. 
 
NATURE OF ALCOHOLIC DRINKS. 59 
 
 76. Home-Made Beer. — Root-beer, small-beer, 
 and various other domestic beers are all made by 
 addinor su2:ar to a decoction of roots or herbs. 
 When the liquid is ''alive" — i. e., full of bubbles- 
 it is bottled, and of course contains alcohol (gen- 
 erally from one to two per cent) as well as carbon 
 dioxide. Since it is the nature of a little alcohol to 
 create an appetite for more, these are not harmless 
 drinks. 
 
 77. Wine. — Wines are made by crushing fruits 
 containing sugar and allowing the juice to ferment. 
 No addition of yeast is necessary in this case, be- 
 cause the '' bloom of the fruit" itself contains micro- 
 organisms that start the fermentation as soon as 
 the juice is pressed out fromi the fruit."^ 
 
 The germs of these microscopic organisms, rest- 
 
 * The micro-organisms which excite vinous fermentation have re- 
 ceived the generic name of Saccharomyces. There are several species 
 of these. That which constitutes the yeast of beer is called Saccharo- 
 7nyces cere^nsicc. One species found on the grape, and thus introduced 
 into the fermenting vat, is Saccharomyces ellipsoideteso " The species 
 most widely diffused in nature, being found on all garden fruits as soon 
 as they are ripe, is Saccharomyces apiculata. It rarely or never occurs 
 on fruit before it is ripe, and if it has shown itself on early-ripening 
 fruits, such as currants, gooseberries, or cherries, it is wanting on others 
 which ripen later — plums and grapes, for instance, as long as they are 
 still green. In the interval between two periods of ripening of the 
 fruit, even in winter, it is found capable of development in the soil 
 beneath the plants whose ripe fruit it attacks, and very rarely in any 
 other place. Distinct spores are not known in this species, only the 
 vegetative cells produced by sprouting. . . . The actual life -history of 
 the plant is therefore very simple, and it is easy to conceive how it 
 finds its way with or from the ripe fruit by the aid of wind or rain to 
 the ground and is carried back with dust from the ground to the fruits, 
 apd its living through the winter in the ground is not at all surprising ; 
 but it has still to be explained why it is so rarely or never found on 
 green fruit or in some other place." — (De Bary's " Morphology and 
 Biology of the Fungi, Mycetozoa, and Bacteria," p. 357.) 
 
6o ORGANS OF REPAIR. 
 
 ing on the outside and stems of fruits, do not exist 
 in the saccharine juices within the fruits themselves. 
 Hence there is no alcohol in whole fruits, vege- 
 tables, or grains as they come to us from the hand 
 of Nature. The sugar of the fruit juices, acted upon 
 by these micro-organisms or ferments, is broken up 
 into carbon dioxide and alcohol, and thereby the 
 juice of healthful fruit is converted into the treach- 
 erous and poisonous liquor called wine. Curiously 
 enough, the alcohol produced by the growth of 
 these organisms is hostile to their own develop- 
 ment, and, after it amounts to a certain percentage 
 (about seventeen per cent) of the fluid in which it is 
 produced, further fermentation is arrested. There- 
 fore, if the grape-juice contains a great deal of su- 
 gar, the alcohol produced finally prevents further 
 changes, and a sweet wine is the result, generally 
 very strong with alcohol. If the amount of sugar 
 is small, a dry wine, containing less alcohol, is the 
 product. 
 
 Cider is properly an apple wine, and is so called 
 by the Germans (apfelwein). As in beers and ales, 
 the alcoholic strength, which is at first slight, in- 
 creases with age, until " hard cider" contains from 
 five to ten per cent. Cider is a drink that has led 
 many to drunkenness. 
 
 78. Other Fermented Liquors. — Perry is pear 
 wine. Wines may be and are made from almost 
 any fruit, as currants, raspberries, blackberries, 
 gooseberries, oranges, etc., for all fruits contain 
 sugar. 
 
 Koumyss, or milk wine, is made among the Tar- 
 tars by fermenting mare's milk, and in this country 
 cow's milk. It owes its effervescence to the pres- 
 
NATURE OF ALCOHOLIC DRINKS. 6 1 
 
 ence of carbon dioxide, and contains from one to 
 three per cent of alcohol, according to age. 
 
 79. Effervescent Drinks. — An essential fact to 
 be borne in mind is that whenever and wherever a 
 liquid containing sugar begins to cast off bubbles 
 it is fermenting ; the bubbles consist of carbon 
 dioxide, and there will inevitably be alcohol re- 
 maining in the liquor. So that all foaming, effer- 
 vescing, lively liquids contain alcohol, provided the 
 effervescence is the result of fermentation. In soda- 
 water (so called) and most artificial mineral waters, 
 the carbon dioxide is manufactured separately and 
 pumped into the liquid by force. In drugs, like 
 Seidlitz powders, etc., and in mineral vraters, it is 
 produced by chemical decomposition, bearing no 
 relation to fermentation and not depending upon 
 the presence of any micro-organism, nor accom- 
 panied by the formation of alcohol. But it will be 
 readily seen that all domestic wines and beers, even 
 w^hat is called small-beer or root-beer, as they de- 
 pend for their palatability upon the development 
 of carbon dioxide, must contain alcohol as well, 
 and are therefore unsafe beverages. 
 
 80. The Tendency of " Light Liquors." — The 
 characteristic tendency of alcohol to create an 
 ever-recurrino- demand for itself is shown bv the 
 liking for stronger liquors that almost universally 
 follows the use of fermented liquors — even the 
 '' lighter ones," that contain only a small per cent 
 of alcohol." 
 
 * The London "Lancet" of December 15, 1888, in an article en- 
 titled " Beer and Drunkenness," says : '* Drunkenness is seizing with 
 a terrible grip the working population of Belgium. Belgium is only 
 surpassed by Bavaria in the consumption of beer, 240 litres a year 
 
62 ORGANS OF REPAIR. 
 
 In wine-making countries, where the people 
 have unlimited access to unadulterated wines, in- 
 cluding both the light wines and those heavier with 
 alcohol, intemperance prevails to an alarming ex- 
 tent. This, according to the testimony of reliable 
 witnesses, is the case in France and Persia, typical 
 wine-growing countries."^ 
 
 8i. Distilled Liquors. — The stronger alcoholic 
 liquors are derived from the weaker ones by the 
 process of distillation. 
 
 Alcohol, and many of the oils and ethers which 
 impart flavor and odor to the various alcoholic 
 liquors, are converted into vapor at a lower tem- 
 perature than water. Therefore, if a dilute solution 
 of these substances is heated, the first ingredients 
 to be driven off as vapor are the alcohol and vola- 
 tile oils, and if the vapor is cooled rapidly as it 
 comes away, it will be condensed into the liquid 
 
 being credited to each inhabitant ; while Russia and Denmark alone 
 surpass Belgium in the consumption of spirit, the average in Belgium 
 being 13 litres a year per inhabitant, or about 50 litres a year per adult. 
 Dr. Petethan stated at Liege in 1886 that there were 100,000 persons 
 in Belgium who drink half a litre of gin per day, and no less than 
 50,000 who drink a whole litre. . . . The outlook is bad for Belgium 
 if the state can do nothing to check this degrading vice." 
 
 * The Rev. J. S. Cochran, long a resident missionary in Persia, 
 says, " In the wine-making season the whole village of male adults will 
 be habitually intoxicated for a month or six weeks." 
 
 Mr. Labaree, also a missionary in Persia, writes : " If I had any 
 sentiments favorable to the use of wine when I left America, my ob- 
 servation during the seven years I have resided in this paradise of 
 vineyards have convinced me that the principle of total abstinence is 
 the only safeguard against the great social evils that flow from the 
 practice of wine-drinking. . . . There is scarcely a community to be 
 found where the blighting influences of intemperance are not seen in 
 families distressed and ruined, property squandered, character de- 
 stroyed, and lives lost." 
 
NATURE OF ALCOHOLIC DRINKS. 63 
 
 form again. This well-known fact affords a cheap 
 and easy method of separating- alcohol from the 
 liquids containing it. The separation in this crude 
 manner is never complete, because, as the tempera- 
 ture of the mixture rises, some water also passes off 
 in vapor and is condensed with the alcohol ; but a 
 liquor is obtained which contains some forty or fifty 
 per cent of alcohol, instead of the five or ten per 
 cent contained in the fluid before distillation. 
 
 The distiller, at about the time when the brewer 
 or vintner bottles up his product or puts it in closed 
 barrels, heats it in a closed vessel, from the top of 
 which a pipe conveys the vapor that arises through 
 a vessel of water kept constantly cold. This pipe 
 is generally made in a spiral or corkscrew form, so 
 as to expose more surface to the cooling effect of 
 the water, and for this reason has been called " the 
 worm of the stilly The condensed liquid falls into 
 a vessel prepared to receive it, and constitutes what 
 is called distilled spirits or liquors. 
 
 82. Distilled Liquors as Beverages. — The most 
 common of these liquors are brandy, rum, whisky, 
 arid gin. Brandy is distilled from wine, or the ref- 
 use grapes from which wine has been made. Rum 
 is distilled from fermented molasses and water, or 
 the fermented juice of the sugar-cane, or the ref- 
 use left from the manufacture of sugar. Whisky 
 is made from malt, by fermenting it with yeast as 
 the brewer does, and then distilling the alcoholic 
 product. Gin differs from other liquors in having 
 been twice distilled. First raw whisky is made, 
 generally from barley, and then it is redistilled 
 w^ith juniper berries, which impart their distinctive 
 flavor to the product. 
 
64 ORGANS OF REPAIR. 
 
 Many other strong alcoholic liquors are pro- 
 duced by the distillation of fruit juices, as black- 
 berry and peach brandy, and apple-jack or cider 
 brandy, distilled from cider. 
 
 All these distilled liquors contain from forty to 
 sixty per cent of alcohol, and are therefore corre- 
 spondingly destructive to health, character, and 
 life. Their distinctive flavor and odor are due to 
 various volatile oils and ethers which pass over 
 with the alcohol as vapor, and are condensed with 
 it, and the color is usually imparted by the wood 
 of the cask in which the liquor is drawn off or by 
 coloring-matters, caramel, etc., intentionally added 
 to it. 
 
 83. Danger of Alcoholic Beverages. — In all 
 these beverages the alcohol is the dangerous con- 
 stituent, and during all the manipulations to which 
 they may be subjected it remains a poison un- 
 changed. Its various injurious effects upon the 
 human system are not due to the weakness of the 
 drinker, but to the nature of the drink. 
 
CHAPTER III. 
 
 MASTICATION. — SWALLOWING. 
 
 84. The Digestive Apparatus. — The food we 
 eat is mostly insoluble, and in an unfit condition 
 to be used for the nourishment of the body. Even 
 so nutritious a substance as albumen can not be 
 used without undergoing some change, and if pure 
 fluid albumen be injected directly into the blood, it 
 will be thrown out of the body by the kidneys un- 
 altered. To prepare the various foods for use in 
 the body, we are provided with a complicated series 
 of organs, called the digestive apparatus, in which 
 the food is ground fine and mingled with various 
 juices until it is reduced to a fluid mass, which can 
 be taken up by the blood and carried to all parts 
 of the body in a condition fit for their nutrition. 
 
 85. Processes to which Food is subjected in 
 the Body. — The process of preparing food for our 
 nourishment may be conveniently divided into 
 five stages. The first of these is inastieation, which 
 takes place in the mouth, and is a voluntary act. 
 The second is swallozving, or the act of passing food 
 on from the mouth to the stomach, the beginning 
 of this act being voluntary, and the greater part of 
 it involuntary. The tJiird is stomacJi digestioti, which 
 is involuntary ; the fourth, intestinal digestion, which 
 
66 
 
 ORGANS OF REPAIR. 
 
 Fig. 19. — Front view of the organs in their natural relations. The heart is 
 partly covered by the lungs, but its true outline is indicated by a dotted 
 line. Only ten ribs are shown on each side, the eleventh and twelfth 
 (the floating ribs) being too short to be included in the section. 
 
MASTIC A TIOX.—S WALLO WLXG. 67 
 
 is involuntary ; and the fifth is the process of ab- 
 sorption, which is also a process of selection, by 
 which certain portions of the prepared mass are 
 taken up into the circulation for food, and the rest 
 left in the intestines as waste material ; this whole 
 process is also beyond the control of our will ; all 
 waste matters are then expelled from the body. 
 
 86. Only One Voluntary Process. — All of these 
 processes must be properly conducted, in order to 
 maintain the body in a healthy condition. They 
 are all important, and, if one be neglected or carried 
 on in a disordered and unnatural manner, the others 
 will all be affected, by reason of their close connec- 
 tion with and dependence on each other. Only one 
 of them is directly under the control of the will, and 
 every one can do more toward preventing dyspep- 
 sia and other disorders of the digestive organs, by 
 paying some attention to the proper and complete 
 mastication of his food than in almost any other 
 way. If we examine the mouth, with reference to 
 its uses in mastication, we find it prepared to per- 
 form three great and important functions. 
 
 87. Use of the Taste and Smell. — In the first 
 place, it is provided with an organ of taste, to assist 
 us in selecting our food. In this it is aided by the 
 proximity of the nose, so that we have the addi- 
 tional advantage of the sense of sinelL And the 
 nose is not only so situated as to aid us in judging 
 of food before it enters the mouth, but it is con- 
 nected with the throat behind, so that odors are 
 detected from substances already in the mouth. 
 
 88. The Teeth. — In the second place, the mouth 
 is provided with organs for grinding and crushing 
 the hard parts of the food, and reducing them to a 
 
68 ORGANS OF REPAIR, 
 
 soft mass, fit to be acted upon by the fluids in the 
 stomach and intestines. The organs directly of 
 use in this operation are the teeth (Fig. 20), but 
 essential aid is aftorded by the mus- 
 cles of the cheeks and the tongue. 
 The rows of teeth are narrow, and, 
 except for the action of these mus- 
 cles, the food could not be kept be- 
 tween them. Indeed, it has been 
 found that in cases of paralysis, 
 when the muscles of the cheek are 
 unable to contract, while the tongue ^ o .• r 
 
 ° Fig. 20. — Section of a 
 
 still retains its power, the food gets tooth. The black 
 pushed out between the cheek and portion is the cav- 
 the teeth, and accumulates there. ntr^eTnf bioodt 
 The lower jaw is moved by some vessels. 
 of the most powerfully acting mus- 
 cles in the body. The chief one of all is the mas'- 
 seter, which is attached above to the ridge of bone 
 running backward from the lower border of the 
 eye toward the ear, and below to the horizontal 
 portion of the jaw. The muscle is nearly square in 
 shape, and, as is easily seen, acts at a great mechan- 
 ical advantage. As a matter of interest connected 
 with this muscle, it may be stated that it is the mus- 
 cle generally referred to for proof that muscular 
 contraction is accompanied by a sound. If the 
 lower jaw be firmly closed, and the teeth powerfully 
 pressed together so that the muscles of mastication 
 are strongly contracted, a low, rumbling sound will 
 be heard, which can not be explained in any other 
 way than as caused by the muscular contraction. 
 
 89. The Saliva. — In the third place, the food, 
 while undergoing mastication, is mixed with cer- 
 
MASTIC. I r/O.V. —SIVALLO WING. 
 
 69 
 
 tain fluids, called collectively the saliva. They are 
 the product of three sets of glands, each of which 
 is double — i. e., there are three glands on each side 
 of the mouth (Fig. 21), and the secretion of each 
 
 
 Fig. 21. — The salivary- glands of the right side. 
 
 pair is peculiar to itself. The largest of these are 
 \\\Q par of id glands, which are situated just in front 
 of the lower border of the ears, and are the glands 
 which become swollen and cause the distortion of 
 the face in the disease known as the mumps. The 
 fluid secreted by these glands is very thin and 
 watery, and constitutes the greater part of the sar 
 6 
 
70 ORGANS OF REPAIR, 
 
 liva. The other glands* are situated just inside the 
 lower border of the jaw and beneath the tongue. 
 Their secretion is much thicker and more glutinous 
 than that of the parotid glands. Besides these 
 fluids, there is a small amount secreted by the 
 mucous membrane lining the mouth, and all these 
 mingled fluids constitute the saliva. 
 
 The saliva is secreted to some extent at all 
 times, and keeps the lining membrane of the mouth 
 moist and soft, but it is a familiar fact that its 
 amount is greatly increased at certain times. Thus, 
 we say, at the sight, or even sometimes at the sug- 
 gestion, of an appetizing meal, the '' mouth waters." f 
 The fact of its excessive secretion at such times 
 shows that it has a part to perform in the process 
 of mastication and digestion. 
 
 90. Properties and Use of the Saliva. — Experi- 
 ments have shown that saliva possesses the property 
 of converting starch into sugar ; but, as this is also 
 done by the digestive fluids, it is not considered to 
 be a very important function, and the chief use of 
 the saliva undoubtedly is, to make the processes of 
 mastication and swallowing of food easier. If food 
 were taken dry, and there were no means at hand 
 of moistening it, mastication would be very difficult 
 and tiresome, and swallowing almost impossible. 
 Bernard % found, by experiments upon a horse, that 
 
 * Submaxillary and sublingual. 
 
 f In physiological lectures before medical students, it is not uncom- 
 mon to illustrate this fact in a curious way. A slender tube is intro- 
 duced into the opening by which the parotid saliva is discharged into 
 the mouth, and, according to the condition of the person operated on, 
 there will either be no flow of saliva or it will come out drop by drop. 
 But now let food be brought in, and the moment it is seen the saliva 
 begins to run from the tube in a plentiful stream. 
 
 % Claude Bernard, a famous French physiologist (1813-1875). ?Ie 
 
MASTIC A TION.—S WALLO WING. 7 1 
 
 when an operation had been performed, which pre- 
 vented the parotid saliva from entering the mouth, 
 the animal could masticate and swallow (the latter 
 process being- accomplished with great difficulty) 
 only three quarters as much oats in twenty-five 
 minutes as he had previously eaten in nine. It is 
 probable that the parotid saliva, which is almost 
 like water, assists mainly in the mastication of the 
 food ; while the other secretions, which are thicker 
 and more slippery, coat the outside of the mass, and 
 render it easier to swallow. 
 
 The total amount of saliva secreted by a healthy 
 adult in twenty -four hours has been calculated, after 
 numerous experiments, to be nearly tJiree poimds. 
 
 Note. — It is important for the health of the individual that the 
 teeth should be kept in good condition, in order that mastication may 
 be thorough and complete. Particles of food which stick between the 
 teeth, if they are allowed to remain, putrefy and impait an offensive 
 odor to the breath. The acids which are developed during the putre- 
 faction of such matters are also injurious to the teeth and tend to hasten 
 their decay. There are also certain substances deposited from the 
 saliva around the necks of the teeth, called "tartar." If this is not 
 removed, the gums are bruised against it, and finally recede from the 
 teeth, leaving a part of the fang bare, and thus exposing to all sorts of 
 injurious influences a part of the tooth which was never intended to 
 be so exposed. 
 
 The teeth should therefore be frequently cleaned, at least twice a 
 day, with water and a soft brush (a stiff bnish injures the gums), tooth- 
 picks being used when necessary. Avoid fancy tooth-powders and 
 washes, for they often contain injurious acids or gritty substances. To 
 polish the teeth, use powdered orris-root and chalk, which can be 
 bought of any druggist. Never crack nuts with the teeth, and, on the 
 slightest appearance of decay, consult a good dentist. 
 
 was Professor of Physiology in the College of France from 1855 until 
 his death. Especially distinguished for his discovery of the formation 
 of sugar in the liver, and for his researches on the functions of the sym- 
 pathetic nervous system. (See later.) 
 
CHAPTER IV. 
 
 STOMACH-DIGESTION. 
 
 91. The Alimentary Canal. — The food, which is 
 now ready to be operated upon by the digestive 
 fluids, passes beyond the control of the person who 
 swallows, and begins its travels in the long tube, 
 called the aliment' ary canal (Fig. 22). This canal 
 begins with the mouth (already described) and ends 
 with the large intestine, and is nearly thirty feet in 
 length. It does not properly assume the form of a 
 tube until the beginning of the cesoph'agus, or gullet, 
 and at one point, namely, at the lower extremity of 
 the oesophagus, there is a considerable enlargement, 
 which has the appearance of a bag or pouch, and is 
 called the stomach. To understand the working of 
 the alimentary canal, it is necessary to know some- 
 thing of its anatomy. 
 
 The two most important tissues in its structure 
 are the mucous membrane which lines it through- 
 out, and the muscles which surround it, and are im- 
 bedded in its walls. 
 
 92. Mucous Membrane. — Mucous membrane (Fig. 
 23) is the skin which lines the interior canals of the 
 body. While the outside of the body is covered 
 by a smooth, white, tough skin, we see that, at the 
 openings leading to its interior, such as the mouth, 
 
S TO MA CH-DIGES TION. 
 
 n 
 
 nose, etc., the character of this covering suddenly 
 changes, and it becomes a reddish or pinkish mem- 
 
 OZSOPHACUS 
 
 Fig. 22. — The alimentar>' canal. 
 
 brane very soft and delicate in texture, and con- 
 tinually moistened by its secretions. This is called 
 mucous membrane, and in one form or another it 
 lines all those internal parts of the body, which 
 communicate with the external air. 
 
 It is made up largely of fibrous tissue, consisting 
 of fine threads, interlacing with each other in every 
 direction and densely woven. Its surface is cov- 
 
74 
 
 ORGANS OF REPAIR. 
 
 ered with minute cells, called epitJie'lial cells.^ At 
 various points on the membrane are minute tubes 
 or cavities, less than 
 i-ir of an inch in diam- 
 
 TOO 
 
 Fig. 23. — Structure of mucous membrane 
 illustrated. At one side is a detached 
 portion of a tube, or follicle, enlarged so 
 as to show the epithelium more clearly,, 
 
 eter,of different shapes 
 in different places, and 
 in some situations so 
 numerous that they lie 
 almost in contact with 
 each other. These mi- 
 nute tubes are closed 
 at the bottom, but 
 open on the surface of the membrane. Small as 
 they are, they are lined from top to bottom with 
 epithelial cells, which really carry on the work of 
 secretion. All around, among, and underneath 
 these tubes are small blood-vessels, which nourish 
 the membrane, and from Avhich the little epithelial 
 cells separate the materials which form the mucus. 
 93. Muscles of the Alimentary Canal. — The mus- 
 cles which form a considerable part of the walls of 
 the alimentary canal are of the involuntary or non- 
 striated kind. The fibers run in various directions, 
 some of them surrounding the oesophagus and the 
 
 * All free surfaces of the body, whether inside or outside, are cov- 
 ered with cells. In the interior of the body, the alimentary canal, the 
 lungs etc., these cells are soft, and, so to speak, plump, and are called 
 epithelial cells, or a mass of them taken together is called epithelium. 
 On the external surface of the body they are diy, flat, hard, and horny, 
 and are called epider mal cells, or, in a mass, the epidenjzis. In both 
 situations they are being constantly shed and renewed. The fresh 
 ones are continually forming underneath, and, as they grow, take the 
 place of the old ones on the surface, which are being constantly rubbed 
 off" in one way or another. All the secretions of mucous membranes 
 contain these epithelial cells, and the slightest scraping of the skin dis- 
 '.odges epidermal cells. 
 
5 TOM A CH- DICES TION. y 5 
 
 intestines in a circle, so that when they contract 
 they make the canal smaller ; while others run 
 lengthwise, and their contraction shortens the ca- 
 nal. When these two kinds of fibers, the circular 
 and the longitudinal, contract together, they propel 
 forward anything that comes within their grasp. 
 
 94. Serous Membrane. — Besides these parts of 
 their structure, the stomach and intestines are cov- 
 ered on the outside by what is called a serous mcin- 
 brane, which is found lining all cavities inside the 
 body that do not communicate with the air, ex- 
 cepting the joints. This kind of membrane is trans- 
 parent, exceedingly fine and soft, and smooth like 
 satin, and is constantly moistened with a slight 
 amount of fluid. The use of serous membrane is 
 to allow organs to move freely upon each other 
 without friction. If it were not for some provision 
 of this sort, the movements of the stomach and in- 
 testines during digestion would be painful, or at 
 least disagreeable, while, as things now are, we are 
 entirely unconscious of any movement at all. 
 
 95. Swallowing. — After mastication is completed 
 the tongue passes the mass of food backward into 
 \\iQ phar' ynx (or throat), whence it goes on into the 
 oesophagus. The cesophagus (Fig. 24) is about nine 
 inches long, and extends from the throat to the 
 stomach, not just behind the breastbone, as many 
 suppose, but just in front of the spine. The mus- 
 cles of the upper portion are of the striated variety, 
 but, nevertheless, their contraction is not voluntary. 
 When an3-thing has once passed to the back of the 
 throat, it will be swallowed and sent into the stom- 
 ach, in spite of our will. 
 
 96. The Stomach. — The stomach varies in size 
 
76 
 
 ORGANS OF REPAIR. 
 
 in different persons, but on the average will con- 
 tain about three pints of fluid in the adult. Its 
 
 *= ri'i 
 
 Fig. 24.— Vertical section of the head and neck. At the base of the tongue 
 IS seen the epiglottis, and below this the larynx. Between the larynx 
 and the bodies of the vertebrae lies the oesophagus. 
 
 shape has often been compared to that of the air. 
 bag of a bag-pipe, which it much resembles (Fig. 
 25). It has two openings, one at the lower extrem- 
 ity of the oesophagus, where food enters, and the 
 other at the point where food passes out and the 
 small intestme begins. These openings are both in 
 
STOMACH-DIGES TIOX. 
 
 7 
 
 the upper border of the organ, and only a short dis- 
 tance apart, Xh^ pylo'rus, or exit, being at the right 
 
 '■') T' ■/ 
 
 Fig. 25. — Outside of the stomach, front view, showing the muscular coat. 
 
 extremity, and the car'diac opening near the mid- 
 dle.'^ The stomach extends toward the left for 
 about three inches beyond the cardiac orifice, and 
 is larger in this part than in any other. This por- 
 tion is called the great pouch of the organ (Fig. 26). 
 Each orifice is guarded by a powerful muscle, 
 surrounding it in a circular form, which can con- 
 tract so tightly as to prevent the passage even of a 
 fluid. As a rule, these muscles prevent the passage 
 of any substance backward through them, in oppo- 
 sition to the natural course of the food. 
 
 * Pylorus, a Greek word meaning the gate-keeper / cardiac, from a 
 Greek word meaning the heart, because it is very near that organ. 
 
78 
 
 ORGANS OF REPAIR. 
 
 97. Stomach-Digestion. — It was formerly sup- 
 posed that the whole process of digestion was 
 
 Fig. 26.— Inside of the stomach, front view, showing the folds (or rugae) of 
 the mucous membrane. 
 
 performed in the stomach, but this is now known 
 not to be the case. The nitrogenous portions of 
 the food are the only ones that are digested in the 
 stomach. The oily and fatty, as well as the starchy, 
 portions are digested in the small intestines. Fluids 
 are very rapidly absorbed by the stomach. 
 
 98. Dr. Beaumont and St. Martin. — There are so 
 many difficulties connected with the investigation of 
 
STOMACH-DIGESTION. 79 
 
 the subject of digestion, that very little was really 
 known about it until the year 1833, when a small 
 book was published by Dr. Beaumont, of the United 
 States Army, giving physiologists their first precise 
 knowledge of what takes place in the human stom- 
 ach. His observations were so well taken, that 
 very Httle has been added since to what he dis- 
 covered upon the particular subject of stomach 
 digestion. 
 
 In the year 1822, Alexis St. Martin, a stout young 
 French Canadian, in the employ of a fur-trading 
 company, and about eighteen j-ears of age, received 
 a severe wound in the left side from the accidental 
 discharge of a shot-gun at a distance of about three 
 feet. He was attended by Dr. Beaumont, and, 
 although his recovery was slow, his health was 
 finally completely re-established, and he was still 
 living in Vermont, the father of a numerous famil}'-, 
 at a very recent date. In the situation of the 
 wound, however, was left an opening into the 
 stomach, about four fifths of an inch in diameter, 
 closed by a fiap or valve of mucous membrane on 
 the inside. This valve could be pushed inward, but 
 not outward ; and thus, although the operation of 
 digestion was not at all interfered with, the interior 
 of the stomach could be thoroughly examined, and 
 experiments performed with the greatest facility 
 and accuracy. Dr. Beaumont kept the young man 
 in his employ for several years, and made hundreds 
 of observations upon him. These were pubhshed 
 in his little book, and made both him and St. Martm 
 immediately famous. 
 
 As Dr. Beaumont was the first, and for many 
 years the only, person who ever saw the interior of 
 
8o ORGANS OF REPAIR. 
 
 the stomach in a living man, much of the following 
 description will be taken from his volume. 
 
 99. Interior of the Stomach. — " The interior coat 
 of the stomach," he says, " in its natural and healthy 
 state, is of a light or pale-pink color, varying in its 
 hues according to its full or empty state. It is of 
 a soft or velvet-like appearance, and is constantly 
 covered with a very thin, transparent, viscid mucus, 
 lining the whole interior of the organ." 
 
 100. The Gastric Juice. — The changes which the 
 food undergoes in the stomach are due to the action 
 of the gastric juice, the appearance of which, with 
 the manner of its secretion, is thus described : 
 
 *' By applying aliments or other irritants to the 
 internal coat of the stomach, and observing the 
 effect through a magnifying-glass, innumerable mi- 
 nute lucid points can be seen arising from the 
 mucous membrane, and protruding through the 
 mucous coat ; from which distils a pure, limpid, 
 colorless, slightly viscid fluid. This fluid is inva- 
 riably distinctly acid." 
 
 " The fluid so discharged is absorbed by the 
 aliment in contact, or collects in small drops and 
 trickles down the sides of the stomach to the more 
 depending parts, and there mingles with the food 
 or whatever else may be contained in the gastric 
 cavity." 
 
 " The gastric juice never appears to be accumu= 
 lated in the cavity of the stomach while fasting. 
 When aliment is received, the juice is given out in 
 exact proportion to its requirements for solution, 
 except when more food has been taken than is necessary 
 for the wants of the system^ 
 
 loi. Composition and Amount of Gastric Juiceo — 
 
S rOMA CH~ DICES TION. 8 1 
 
 The gastric juice contains two important constitu- 
 ents, viz., hydrochloric acid and pepsin. If it be 
 deprived of these, it will no longer exhibit its pe- 
 culiar properties ; while, if it retains them, as Dr. 
 Beaumont first showed, it will digest food in a glass 
 tube, outside the body, provided the tube and its 
 contents be kept at a temperature of ioo° Fahr., 
 which is about the ordinary temperature inside the 
 stomach. 
 
 The average amount of gastric juice secreted 
 daily by an adult human being has been estimated 
 at a little less than fourteen pounds^ or about a gallon 
 and a half. 
 
 102. Movements, of the Stomach. — But, besides 
 the action of the gastric juice in stomach-digestion, 
 a ver}^ important office is performed by the muscles 
 which form a large part of the walls of the organ. 
 During digestion, these muscles are continually 
 contracting in a slow, regular order, producing 
 movements of the contents of the stomach in a 
 very peculiar manner, which, in health, never varies. 
 Dr. Beaumont says that the ordinary course and 
 direction of the revolutions of the food are first, 
 after passing out of the oesophagus into the stom- 
 ach, from right to left, thence down along the great 
 curvature, from left to right, to the pvlorus, whence 
 it returns again along the upper border of the or- 
 gan to the left extremity of it. Each of these jour- 
 neys of the food around the organ occupies from 
 one to three minutes, and they serve to mingle the 
 gastric juice more thoroughly with the food. As 
 soon as the process of digestion is gone so far as to 
 bring portions of the food into a condition for ab- 
 sorption, it is found that every tune the contents of 
 
82 ORGANS OF REPAIR. 
 
 the stomach pass the pylorus the mass becomes di- 
 minished in amount, showing that a portion has 
 been squeezed or pressed through the opening into 
 the intestine. 
 
 " These pecuhar motions and contractions con- 
 tinue until the stomach is perfectly empty, and not 
 a particle of food remains. Then all becomes quiet 
 again." 
 
 Thus that part of the digestion of food which is 
 carried on in the stomach is accomplished by the 
 action of the gastric juice, and the changes pro- 
 duced by it are assisted, and the prepared food is 
 passed out of the stomach, by the constant contrac- 
 tions and churning motions of the organ just de- 
 scribed. 
 
 This, then, is the ordinary healthy process of 
 stomach-digestion, when not in any way hindered 
 or interfered with. Let us see what changes take 
 place in the appearance of the stomach and in its 
 functions when it is injuriously affected. 
 
 103. Appearance of the Stomach during Indi- 
 gestion. — " In a feverish condition, from whatever 
 cause — obstructed perspiration, undue excitement 
 by " alcoholic " liquors, overloading the stomach 
 with food — fear, anger, or whatever depresses or 
 disturbs the nervous system," the lining of the stom- 
 ach '' becomes somewhat red and dry, at other times 
 pale and moist, and loses its smooth and healthy 
 appearance ; the secretions become vitiated, greatly 
 diminished, or entirely suppressed." 
 
 " There are sometimes found, on the internal 
 coat of the stomach, eruptions or deep-red pimples. 
 These are at first sharp-pointed and red, but fre- 
 quently become filled with white purulent matter; 
 
5 TO MA CH- DICES TION. 8 3 
 
 at other times, red patches, from half an inch to an 
 inch and a half in circumference, are found on the 
 internal coat. These appear to be the result of con- 
 gestion in the minute blood-vessels of the stomach." 
 
 "These diseased appearances, when very slight, 
 do not always affect essentially the gastric appa- 
 ratus. When considerable, and particularly when 
 there are corresponding symptoms of disease, as 
 dryness of the mouth, thirst, furred tongue, etc., 
 no gastric juice can be extracted. Drinks received 
 are immediately absorbed or otherwise disposed 
 of ; none remaining in the stomach ten minutes after 
 being swallowed. Food, taken in this condition of the 
 stomachy remains ^indigested for tzuentyfour or forty^ 
 eight hours or more.'' 
 
 " Whenever this morbid condition of the stom- 
 ach occurs, with the usual accompanying symptoms 
 of disease, there is generally a corresponding ap- 
 pearance of the tongue. When a healthy state of 
 the stomach is restored, the tongue invariably be- 
 comes clean." 
 
 These are the observations of one who sa^^ what 
 he describes, and took careful notes of what he 
 saw. 
 
 104. Time required for Stomach-Digestion. — The 
 time required for digestion in the stomach varies 
 very much according to the character of the food. 
 Dr. Beaumont found that the time of stomach-di- 
 gestion in St. Martin varied from one hour to about 
 five and a half. Among meats, the soonest digested 
 was boiled pig's feet, which took an hour, and the 
 longest time was taken for roast pork, viz., five 
 hours and a quarter ; among vegetables, rice is di- 
 gested in an hour, while boiled cabbage requires 
 
84 ORGANS OF REPAIR, 
 
 four. The average time required for an ordinary 
 meal is probably about three hours. 
 
 105. Advantage of Thorough Mastication. — Dr. 
 Beaumont found that, when a piece of meat or other 
 food is attacked by the gastric juice, it is slowly 
 dissolved from the outside. The juice is not soaked 
 up and does not penetrate the interior of the mass, 
 but gradually softens the exterior of it ; and, as 
 the outside portion becomes friable and dissolves, 
 the piece grows smaller and smaller, the gastric 
 juice in this way advancing little by little, until the 
 whole mass is liquefied. From this it is evident 
 that it will take longer to digest a large piece of 
 meat than to digest the same amount after it has 
 been divided into small pieces ; for this reason it is 
 important to masticate the food thoroughly before 
 sending it into the stomach. 
 
 106. Eating too little. — It is evident that it will 
 not do to take too little food. Enough must be 
 eaten to supply the needs of the system, and it 
 must be of such a quality that it can be readily di- 
 gested and appropriated. 
 
 107. Eating too much. — But, on the other hand, 
 we miLSt not take too mncJi food. There seems to be 
 some subtile relation between the amount of food 
 required by the system and the amount of gastric 
 juice furnished by the stomach. What is likely to 
 be the result, then, if more food is taken into the 
 stomach than can be acted on by the gastric juice ? 
 Let us consider.^ The temperature of the interior 
 of the stomach is about 100° Fahr. This is just 
 about the temperature at which fermentation and 
 putrefaction (which is one kind of fermentation) are 
 most active. Heat and moisture favor these pro- 
 
STOMACH-DIGESTION. 85 
 
 cesses. Both of these conditions exist in the stom- 
 ach, but, under ordinary circumstances, the gastric 
 juice prevents any other changes than those due 
 to its own action. But, if more food is introduced 
 than the gastric juice can dissolve, fermentation 
 occurs, and offensive gases and irritating acids are 
 produced. Then the symptoms of indigestion come 
 on, there is constant belching of wind from the 
 mouth, an uneasy sensation in the stomach, and, as 
 soon as the undigested and fermenting mass passes 
 Dut into the intestine, rumblings and colic set m, 
 followed probably by a diarrhoea, which continues 
 until the offending matters have been ejected from 
 the body. 
 
 108. Eating between Meals. — Similar symptoms 
 may be produced by eating between vicals. When a 
 sufficient meal has already been eaten, we should 
 wait until it has been digested and the stomach has 
 had a short period of rest before we give it any 
 more work to do. This organ can not work inces- 
 santly any more than other parts of the bod}', and 
 when it is ready for more food the sensation of 
 hunger apprises us of the fact. If we load it with 
 fresh food before the previous supply has been dis- 
 posed of, there may not be enough gastric juice 
 secreted to digest it. Then it ferments, or putre- 
 fies, and causes a fit of indigestion, as just described. 
 
 109. Hunger. — It is sometimes said that a person 
 should rise from the table, after every meal, still 
 hungry. This is not correct, and the reason is 
 plain. Hunger is the natural indication that the 
 body is beginning to be worn out, and needs fresh 
 material to repair its losses. And although the 
 appropriation of the food is finally made b}' the 
 
 7 
 
86 ORGANS OF REPAIR. 
 
 cells that compose the body, and so must be after 
 it has been already digested and carried to them, 
 nevertheless the sympathy of the different parts of 
 the body with each other is such that hunger is 
 satisfied by the mere act of supplying food to the 
 stomach. Not only that, but the digestibility of 
 the food has a great deal to do with it. Certain 
 kinds of food, which we call rich, generally contain- 
 mg a great deal of fat and sugar, satisfy the hunger 
 and produce a sense of satiety, when we have not 
 really eaten enough to supply the bodily needs. 
 This is because such food is digested very slowly, 
 being so permeated with fat that the gastric juice, 
 which does not digest fat, penetrates to the albumi- 
 nous portions of the food with great difficulty. In 
 such cases also fermentation frequently occurs, and 
 persons who eat much so-called rich food may satis- 
 fy their hunger with it day after day, and still suffer 
 from indigestion, and not get enough nourishment 
 to repair the waste of the body. For these reasons, 
 plain food is the best, especially for the young. 
 
 IIO. How much to eat. — The true way, there- 
 fore, is not to rise hungry from the table, but to 
 stop eating when the hunger has been satisfied, and 
 before any feeling of repletion comes on. It should 
 be borne in mind that the process of digestion 
 ought to go on without our consciousness. After 
 a proper meal, the only sensation caused by the 
 food we have taken should be that of complete 
 satisfaction and contentment. If the stomach feels 
 stuffed and full, we have eaten too much. It may 
 be properly disposed of if the eater is in vigorous 
 health, and able to rest for a time until the uneasy 
 feeling of repletion wears away. But the whole 
 
STOMACH-DIGESTION. 8/ 
 
 process ought to go on without causing us a mo- 
 ment's thought. If we are healthy, and if we treat 
 our digestive organs properly, we ought never to 
 feel that Ave have a stomach, or liver, or bowels. 
 They will never trouble us, if we do not trouble 
 them. 
 
 Our meals, therefore, should be sufficiently far 
 apart to allow an hour or two at least to intervene 
 between the digestion of one meal and the begin- 
 ning of another. As digestion in the human being 
 ordinarily occupies from three to lour hours, our 
 meals should be at least five hours apart, and this 
 is about the time usually allowed. 
 
 111. What to eat. — The matter of what to eat, 
 amid the great variety of foods, may safely be left, 
 in a healthy person, to the appetite. It is a familiar 
 proverb that " one man's meat is another man's 
 poison." Each individual must learn for himself 
 what food is the best for him. If an}- article is 
 found to disagree, it should thereafter be let alone ; 
 no attempt should be made to overcome a natural 
 repugnance, and acquire an appetite for what is 
 distasteful. This is to fly in the face of Nature ; it 
 is much the same as saying that one is competent 
 to direct the secret processes of nutrition and to 
 regulate the functions of organs, about which he 
 knows almost nothing, and Avhich he can not con- 
 trol. Such action is intermeddling, not judicious 
 care. 
 
 112. Condiments. — Something should here be 
 said, however, about the use of certain substances 
 which are not foods, and yet are in common use 
 throughout the world, to make food more accepta- 
 ble to the palate. Such substances are pepper and 
 
88 ORGANS OF REPAIR. 
 
 mustard. These condiments have two qualities 
 that have caused them to be used in the prepara- 
 tion of food, viz., a peculiar flavor, which makes 
 articles of food to which they have been added 
 more savory, and a quality called pungency — i. e., 
 they irritate any part of the body with which they 
 are brought in contact. When either is placed 
 upon the tongue, smarting is produced, sometimes 
 to a painful degree, and tears start in the eyes. 
 The effect can therefore be imagined when these 
 substances are rubbed over the delicate mucous 
 lining of the stomach during the movements of 
 digestion. They can not but be extremely irritat- 
 ing, and therefore injurious. As a matter of fact, 
 the excessive use of such things, whether alone 
 or in highly-seasoned sauces (Worcestershire, etc.), 
 results in extreme debility of the digestive appara- 
 tus and confirmed dyspepsia. The golden rule in 
 the treatment of the stomach is, to put nothing into 
 it that can be felt after entrance. As before stated, 
 the operations of the stomach ought to go on with- 
 out our consciousness of them. If enough spice is 
 taken to produce a feeling of warmth in that organ, 
 it is too much, and the mucous membrane has been 
 irritated. We are all, or nearly all, born into the 
 world with sound digestive organs, which need no 
 spurring to make them do their duty. If they get 
 out of order, it is our own fault, and rest will do 
 more than anything else to set them right. If you 
 whip a good horse, when he is doing his best, you 
 will spoil him. 
 
 113. The Natural Drink. — The natural drink of 
 all animals is water, for milk is to be looked upon 
 as a food. Many people, however, are not satisfied 
 
S TO MA CH-DIGES TIOX. 
 
 89 
 
 with water aione, but prefer it flavored with some- 
 thing else, and a great variety of drinks have been 
 invented. We shall consider here the effect that 
 some of these drinks, such as tea, coffee, and those 
 which contain alcohol, as malt and spirituous liquors 
 and wines, have upon the stomach. 
 
 114. Tea and Coffee. — Tea and coffee are found 
 to stimulate the nervous system, producing slight 
 exhilaration and relieving exhaustion without the 
 subsequent depression that follows the use of alco- 
 hol. In excess, however, they produce nervous 
 disorders, and probably all persons would be better 
 without them. Their influence upon the nerves, 
 the most impressionable part of a growing person, 
 renders them unsuitable articles of diet for the 
 young. 
 
 115. Irritant Effect of Alcohol. — If clear alcohol 
 is introduced into the stomach in small quantity, it 
 acts as an irritant, causing an increased secretion of 
 mucus. The mucous membrane lining the interior 
 of the organ becomes red and congested. If a large 
 quantity be introduced at once, the irritation of the 
 nerves of the stomach is so great that important 
 nervous centers are affected, and extreme depres- 
 sion immediately follows, soon ending in death. 
 
 116. Effect of Diluted Alcohol on the Stomach. 
 — The effects of diluted alcohol, as in the various 
 alcoholic beverages, differ in degree according to 
 the amount of alcohol they contain. A small amount 
 of alcohol, introduced into the stomach in this way, 
 produces slight congestion and reddening of the 
 mucous membrane, and excites the secretion of gas- 
 tric juice, much as a small quantity of pepper might 
 do. As alcohol coagulates albumen, and when add- 
 
90 
 
 ORGANS OF REPAIR, 
 
 ed to gastric juice outside of the body precipitates 
 its pepsin and takes away its property of digesting 
 food, it must be inferred that it will have a similar 
 effect upon these substances when brought into 
 contact with them in the stomach. This has been 
 found to be the case when alcohol is taken in con- 
 nection with food. As long as it remains in the 
 stomach in any degree of concentration, the process 
 of digestion is arrested, and is not continued until 
 enough gastric juice is thrown out to overcome the 
 effects of the alcohol. In large amount, alcoholic 
 drinks often stop digestion entirely until the alco- 
 hol has been absorbed. 
 
 117. Effect of Large Amounts of Alcohol on 
 the Stomach. — If alcohol be taken to the point of 
 intoxication, the reaction after it has passed out of 
 the body is very marked in the digestive organs. 
 The pit of the stomach is tender to pressure, there 
 are nausea and retching, with perhaps vomiting of 
 mucus and bile. The tongue is heavily coated Avith 
 fur, there is intense thirst, and entire loss of appe- 
 tite. These symptoms indicate an acute catarrh 
 of the stomach, and may not disappear for several 
 hours. 
 
 118. Chronic Disease of the Stomach caused by 
 Alcohol. — If the stomach is constantly being irri- 
 tated by the habitual use of alcohol, serious changes 
 result. The mucous membrane becomes perma- 
 nently congested and covered with a thick, un- 
 healthy, tenacious mucus, which sets up fermenta- 
 tion in the food, giving rise to what is called a sour 
 stomach, heart-burn, and nausea, and sometimes 
 vomiting of bile on rising in the morning. If warn- 
 ing is not taken in time, and the use of such drinks 
 
STOMACH-DIGESTION. 
 
 91 
 
 discontinued, the connective tissue of the mucous 
 membrane becomes greatly developed, the walls of 
 the stomach are thickened, the glands that secrete 
 the gastric juice are pressed upon and many of them 
 starved out of existence, so that the normal secre- 
 tions that are necessary to digestion are scanty, 
 and chronic and incurable dyspepsia results. 
 
 119. Effect of Opium on the Stomach. — Opium, 
 when taken into the stomach, deadens the gastric 
 nerves, and diminishes or entirely suspends the se- 
 cretion of the gastric juice. It therefore interferes 
 greatly with digestion. By deadening the nerves 
 it diminishes hunger. It also in the same way 
 prevents proper intestinal digestion (see next chap- 
 ter), produces obstinate constipation, and thus seri- 
 ously impairs the nutrition of the body. In many 
 people the introduction of opium into the stomach 
 is followed, after the narcotic effects have passed 
 away, by nausea and vomiting and great prostra- 
 tion The same symptoms may follow^ the similar 
 use of morphia. If the latter drug is administered 
 by injection under the skin, so that it is immediate^ 
 absorbed into the blood, the stomach symptoms 
 may be entirely absent and the digestive powers 
 undisturbed." 
 
 In old opium-eaters this constant interference 
 with the digestion and appropriation of food re- 
 sults in extreme emaciation, so that they may look 
 almost like skeletons covered with parchment tight- 
 
 * The injection of morphia under the skin is sometimes followed 
 by considerable irritation and even by a small abscess. If time is not 
 allowed for the part to recover its natural condition before a second 
 injection, inflammation is almost sure to follow. Hence the trunk and 
 limbs of those who take morphia habitually in this way arc generally 
 covered with abscesses and the scars of those that have healed. 
 
92 
 
 ORGANS OF REPAIR. 
 
 ly drawn over the bones. In some cases, how^ 
 ever, even confirmed opium-eaters will recover a 
 certain degree of appetite and digestive power, 
 and the constipation be replaced by a diarrhoeal 
 condition. 
 
 120. Effect of Tobacco due to the Nicotine. — 
 The effects of tobacco upon living organisms are 
 mainly due to the nicotine it contains. This sub- 
 stance is a virulent poison, producing death, when 
 given in a fatal dose, in less time than any other poi- 
 son excepting prussic acid. During the operation 
 of chewing or smoking it is absorbed by the mucous 
 membranes, but is believed to be rapidly passed 
 out of the body again, for there is enough nicotine 
 in an ordinary cigar to kill the smoker if it were 
 all taken into the system at once. 
 
 121. General Effect of Tobacco upon the Human 
 Body. — When tobacco is taken by one who is unac- 
 customed to its use, or by any one in a poisonous 
 dose, it irritates the mucous membrane of the 
 mouth, causing an increased flow of saliva, soon 
 giving rise to uneasy sensations in the stomach 
 and bowels, nausea, vomiting, great distress at the 
 pit of the stomach, a feeling of intense anxiety, 
 giddiness, dimness of vision, and great feebleness 
 and general prostration. The surface of the body 
 becomes cold and clammy, the forehead is be- 
 dewed with perspiration, and, if the dose of to- 
 bacco has been sufficient, convulsions follow, and 
 then death. 
 
 122. Effect of the Habitual Use of Tobacco 
 upon the Digestive Organs. — Even in one habitu- 
 ated to its use, tobacco excites the flow of saliva, 
 and has therefore been supposed by some to im- 
 
STOMACH-DIGESTION. 
 
 93 
 
 prove the digestion. But the natural stimulant of 
 the salivary glands is food, and the outflow of saliva 
 in a healthy person is properly proportioned to the 
 quantity of food masticated, so that there is no need 
 of any artificial stimulus, and the excess of saliva 
 is harmful instead of beneficial. This is abundantly 
 shown by the dyspepsia that almost always affects 
 habitual smokers. Few of them can digest a meal 
 without a cigar, and few of them have a clean pink 
 tongue. It is almost invariably coated, a sure sign 
 that the stomach is in an unhealthy condition. It 
 is also probable that tobacco affects the nervous 
 supply of the stomach sufficient!}^ to interfere to 
 some extent with the secretion of the gastric juice, 
 and with the muscular movements which are neces- 
 sary to good digestion, though this can not be said 
 to have been proved. If it were only generally 
 known that the organs of a healthy body, such as 
 most of us start out in life with, need no prodding 
 to do their work satisfactorily, there would be less 
 sickness and longer lives. 
 
 The excessive secretion of saliva induced by the 
 use of tobacco is followed by dr^-ness of the mouth 
 and throat, a natural result of the overwork forced 
 upon the salivary glands. This dryness leads in 
 many persons to the drinking of alcoholic bever- 
 ages, water only satisfying the thirst temporarily, 
 w^hile the alcohol keeps up the excitement of the 
 glands, which was started by the tobacco. The 
 excitement produced by the alcohol, on the other 
 hand, can be subdued to some extent by the seda- 
 tive tobacco. So these drugs play into each 
 other's hands, as it were, and keep their slave in 
 a sort of merry-go-round, the price he pays being 
 
94 
 
 ORGANS OF REPAIR. 
 
 a loss of health and often of reputation and men- 
 tal vigor. 
 
 123. Opium not a Food. — Although opium can 
 not be regarded as a food in any sense of the word, 
 it is habitually eaten by many people, particularly 
 by Oriental people, as the Chinese and Javanese. 
 It never acts, however, as a food, but, like other 
 narcotics, it has the property of blunting the sensi- 
 tiveness of the nerves and nervous centers, and 
 thus it renders the sensations of hunger and fatigue 
 less imperious, and enables persons to go longer 
 without food or rest than they otherwise could. 
 The lack of food and rest, however, is attended 
 with great waste of unreplenished tissue, and con- 
 sequent weakening of the vital forces. 
 
 124. Confectionery. — Confectionery is not injuri- 
 ous, when pure, unless taken in excess. Unfortu- 
 nately, it is frequently adulterated, and, instead of 
 containing simply sugar, flour, gum-arabic, and 
 such harmless substances, is mixed with terra alba 
 (gypsum), because it is heavy and cheap. Poison- 
 ous coloring-matters are also used. All candy that 
 has a gritty feeling in the mouth should be re- 
 jected, and bright-yellow, orange, and green can- 
 dies are to be looked on with suspicion, for 
 they are almost always colored with chromate of 
 lead. 
 
 125. Danger of Parasites in Food. — A word of 
 caution is necessary about the eating of pork. This 
 meat occasionally contains millions of minute para- 
 sitic worms, called the tricln'na spira'lis, and, if such 
 meat is eaten without killing these worms, they are 
 set free in the alimentary canal, bore their way into 
 the blood-vessels, and are carried by the current of 
 
S TO MA CH- DICES TION. 
 
 95 
 
 blood all over the body. When they come to ves- 
 sels so small that they can not pass, they are stuck, 
 dam up the blood-current, interfere with the circu- 
 lation, and produce serious and often fatal disease. 
 These parasites are killed by a temperature of i6o° 
 Fahn, and pork, therefore (including ham, of course), 
 should never be eaten unless it is thoroughly 
 cooked.* It is now known that many diseases are 
 caused mainly by the presence of living micro- 
 scopic organisms in drinking-water, typhoid fever, 
 for example ; and the immunity of the Chinese 
 from this disease has been attributed to the fact 
 that they only drink water that has been boiled, 
 usually in tea. 
 
 Briefly, then, to keep the stomach healthy, masti- 
 cate the food tJwroiigJily, eat ivhen you eire hungry^ 
 avoid overeating and eating betiveen meals, eat plain 
 food, do not spur the stomach luitJi condiments or appe- 
 tizers, sJiun alcoholic drinks, and use tea and coffee, if 
 at all, with the greatest moderation and caution. 
 
 * The flesh of the pig occasionally contains another parasite, called 
 the cysticcr' cus cclhclo'soo, which, if taken alive into the stomach, devel- 
 ops into the tape-worm. This parasite, like the trichina^ is killed by 
 thorough cooking. 
 
CHAPTER V. 
 
 INTESTINAL DIGESTION. 
 
 126. The Chyme. — After the partially digested 
 food has passed out of the stomach into the intes- 
 tine, it undergoes still furthfer changes, and the 
 difhculties of investigation in this part of the body 
 are so enormous that very little progress has been 
 made toward a clear explanation of what takes 
 place there. Enough has been learned, however, 
 to give us a general idea of how the process of di- 
 gestion is completed. 
 
 We have seen that the fats and the starches 
 are not digested in the stomach. The gastric juice 
 does not act upon them at all, and they pass into 
 the intestine in very much the same condition in 
 which they enter the stomach. The fibers and tis- 
 sues which hold the fats and starches together, 
 being nitrogenous in their nature, are acted upon 
 in the stomach and dissolved, so that the fat is set 
 free and floats in globules like those upon the sur- 
 face of a kettle of soup. The food thus prepared 
 to pass into the intestine forms a thick, turbid, gray- 
 ish fluid, called the chyme. 
 
 127. The Intestines.— The small intestine, into 
 which the food passes from the stomach, is a tube 
 about twenty feet in length, and an inch in diame- 
 
INTESTINAL DIGESTION. 
 
 97 
 
 ten It is composed, like the stomach, of three 
 layers, the innermost one being mucous membrane, 
 the middle one muscular fibers, some of which are 
 circular and some longitudinal, and the outer layer 
 serous membrane.* 
 
 The small intestine is connected with the large 
 one by a valve-like opening situated in the vicinity 
 of the right groin. The lai^ge intestine passes from 
 this point upward to the liver, thence across to the 
 left side, and then downward, constituting the last 
 five feet of the alimentary canal. f 
 
 128. Muscular Fibers of Intestine. — The ninsciilar 
 fibers of the intestine contract with a worm-like 
 motion, which always begins near the stomach, and 
 extends slowly along the whole length of the intes- 
 tine, gradually emptying it of its contents. In this 
 
 * The outer membrane of the in- 
 testine of animals, when separated from 
 the rest, is used for sausage-casings, 
 and, when properly prepared, also 
 makes what is called gold-beater's skin, 
 f The beginning of the large intes- 
 tine is situated in the right groin, and 
 forms a sort of bag or pouch, called 
 the ccecum. From one side of this 
 pouch there projects a slender tube re- 
 sembling the intestine in structure, and 
 about six inches long. This is called 
 the appendix venniformis, i. e., the 
 worm-like appendage (Fig. 27). In 
 man it seems to be entirely useless, and 
 is in fact a constant source of danger ; 
 for occasionally small objects, like 
 cherry-pits and grape-seeds, which are 
 swallowed with the food and not di- 
 gested, become lodged in it, and grad- 
 ually produce an irritation wb.ich results in an abscess, and destroys 
 life. Such cases are not uncommon in medical practice. 
 
 Fig. 27. — Junction of the small 
 and large intestines, and the 
 appendix vermiformis. The 
 large intestine / here called the 
 LLeciiin) is cut away so as to 
 show the internal openings. 
 
98 
 
 ORGANS OF REPAIR. 
 
 slow passage of the food from the stomach through 
 the small intestine to the large one, it is mingled 
 with various fluids which complete the process of 
 digestion, and the nutritious portions of the mass 
 are absorbed and carried away by the blood and 
 other vessels. 
 
 129. The Duodenum. — The first eight or ten 
 inches of the small intestine are somewhat larger 
 than the remainder, and are called the duode' num, 
 because its length is about twelve fingers' breadth. 
 Into this duodenum empty small canals from two 
 very important organs, viz., the pan'creas and the 
 liver. 
 
 130. The Pancreas. — The pancreas (Fig. 28), 
 
 Fig. 28. — The pancreas, partly cut away, so as to show the duct, which 
 collects the pancreatic juice, and empties it into the duodenum. 
 
 which we call the sweet-bread when we cook it for 
 food,"^ is about six inches long, is shaped somewhat 
 
 * There are three kinds of sweat-breads, viz. : the thyroid-gland, 
 or throat sweet-bread, which is tough, almost like India-rubber; the 
 pancreas, or belly sweet-bread, which is more tender, and is quite com- 
 monly used ; and the thymus-gland, or breast sweet-bread, which, 
 exists only in young animals, wasting away as they grow up. This 
 gland is situated just behind the upper portion of the breastbone, at- 
 tains its greatest size in human beings at the age of two years, and 
 disappears before the sixteenth year. Its use is not known. This 
 
INTESTINAL DIGESTION. 99 
 
 like a pistol, and is situated behind the stomach, 
 with the large end, or the breech of the pistol, 
 toward the right. It secretes a fluid, called the 
 pancreat'ic juice, which has been shown to be the 
 chief agent in the digestion of the fatty portions of 
 the food. If a quantity of oil be shaken up with pan- 
 creatic juice, a white, opaque, creamy fluid is formed, 
 in which the drops of oil or fat are not visible any 
 more than they are in ordinary milk or cream. Mi- 
 croscopic examination, however, shows that the oil 
 is not in any way decomposed, but is divided into 
 very minute particles, in which condition it can 
 be absorbed by the proper channels. In this way 
 fat is taken up into the circulating fluids in its own 
 proper form, and does not undergo decomposition 
 until it reaches other parts of the body, if at alL 
 The pancreatic juice also liquefies the nitrogenous 
 matters which may have passed the pylorus undi- 
 gested, and changes the starch into sugar. In fact, 
 it seems to be the chief agent in completing the act 
 of digestion, which has begun in the stomach. 
 
 131. The Liver. — The liver (Fig. 29) is a very 
 large organ, the largest and heaviest in the body, 
 weighing in a healthy adult from three to four 
 pounds, and situated on the right side, protected by 
 the lower four or five ribs. It secretes the bile, and 
 from its size, and the amount of its secretion, is 
 evidently one of the most important organs in the 
 body, and yet its precise use is still a matter of dis- 
 pute and doubt. 
 
 132. Liver-Sugar. — It was long supposed that the 
 only function of the liver was to secrete the bile ; but 
 
 gland, taken from calves and lambs, is the most tender and palatable 
 sweet-bread of ail. 
 
lOO 
 
 ORGANS OF REPAIR. 
 
 it has been found, in recent years, that it also forms 
 a kind of sugar in large amount. The blood which 
 enters the liver is found to contain a small amount 
 
 Fig. 29. — Under surface of the liver. 
 
 of sugar, while that which flows away from it, after 
 having circulated through it, always contains sugar 
 in considerable quantity. Even this fact, well estab- 
 lished as it seems to be, is still a subject of dispute 
 among experimental physiologists. 
 
 133. The Bile. — The bile is a somewhat glutinous 
 fluid, of a rich, golden-red color,'^ which is dis- 
 charged into the duodenum through the same open- 
 
 * When vomiting takes place and lasts for a time, the intestines 
 reverse their action, and bile is carried backvv'ard through the pylorus 
 into the stomach. It is here out of place, and produces extreme nausea. 
 Its color is changed by the gastric juice to a greenish yellow. 
 
INTESTINAL DIGESTION, loi 
 
 ing with the pancreatic juice.* It must, therefore, 
 become mingled with the food long before digestion 
 is completed. The natural inference from this is 
 that it has something to do with the process ; but 
 the digestion of every portion of the food can be 
 accounted for in other wavs. Nitrosfenous matters 
 are digested in the stomach, while the fatty mat- 
 ters and the starches are digested by the pancre- 
 atic juice, assisted, perhaps, by the intestinal juices, 
 to be hereafter spoken of. It would appear, then, 
 that there is nothing left for the bile to do, and 
 that it must be an excrevicntitioiis fluid — i. e., that 
 it consists of matters which have been separated 
 from the blood by the liver because they are hurt- 
 ful to the organism, and must, therefore, be ex- 
 pelled from the body. This was the ancient view, 
 and it seemed to be supported by the fact that, if 
 the liver be diseased so that this separation can 
 not take place, and the constituents of the bile re- 
 main in the hXoooi, jaundice occurs, and, if there is 
 no relief, the person dies with all the svmptoms 
 of poisoning. So far, it seems plain enough that 
 the bile has no office to perform in the body, but 
 is only secreted to be expelled. But operations 
 have been performed of such a kind that the action 
 of the liver was not interfered with, and yet the 
 bile could not enter the intestine, but had to be 
 discharged outside the body through an artiti- 
 cial opening. Under such circumstances, if the 
 
 * As soon as the partially digested food, containing a certain amount 
 of gastric juice, passes the opening of the bile-duct, there is a great 
 gush of bile into the intestine. It is found that any acid, applied to 
 this opening, will produce the same effect. The bile, being alkaline, 
 neutralizes the gastric juice, which is therefore of no further use, and 
 so the digestive process has to be completed by other means. 
 8 
 
I02 ORGANS OF REPAIR. 
 
 bile be simply an excrementitious fluid, its dis- 
 charge from the body by one channel rather than 
 by another ought not to make any difference in 
 the health. But it is found, on the contrary, that 
 operations of this nature are followed by every 
 appearance of starvation. The appetite remains 
 good, the digestion is not interfered with ; but, 
 nevertheless, although food is supplied in abun- 
 dance, extreme emaciation follows, and death gen- 
 erally in about a month. These facts show con- 
 clusively that the bile has some important part to 
 play in the nutrition of the body. 
 
 It is found, moreover, by actual chemical exami- 
 nation of the excretions, that the bile, although it 
 is discharged into the intestine, does not all leave 
 the body. It must, then, be reabsorbed into the 
 circulation. But, if this be so, why does it not give 
 rise to symptoms of poisoning, just as if it were 
 prevented from leaving the blood in the first place? 
 The only possible answer to this is, that it is some- 
 how changed in the intestine, so that when it is 
 reabsorbed it is harmless. 
 
 134. The Intestinal Juices. — Besides the bile 
 and pancreatic juice, the food meets in the small 
 intestine with the intestinal juices proper. Of these 
 very little is known with certainty, owing to the 
 great difficulty of obtaining them from the Jiving 
 organism unmixed with other fluids. The small 
 intestine is lined, however, with a mucous mem- 
 brane containing millions of small tubules and 
 glands, which secrete certain colorless alkaline 
 fluids. Of these fluids it is both affirmed and de- 
 nied that they possess the property of turning 
 starch into sugar with great rapidity ; but, so far 
 
INTESTINAL DIGESTION, 103 
 
 as is known, their part in the process of digestion 
 is not important. 
 
 135. Absorption of Food. — If animals are killed 
 at different times after the eating- of food, and dif- 
 ferent portions of the intestine are examined, it is 
 found that, while the upper portion of the small 
 intestine contains a large amount of partially-di- 
 gested food, the lower portion contains the shriv- 
 eled remnants of muscular tissue, the husks of 
 grains, the woody, indigestible fibers of vegetables, 
 etc. ; in short, the unappropriated residue of the 
 food which has been taken. The great mass of 
 what has been eaten has disappeared, and after a 
 certain time the whole intestine will be found 
 empty. There are two systems of vessels by which 
 this absorption of food is accomplished — they are 
 the blood-vessels and the lacteals.^ 
 
 136. The Peritonaeum. — To understand the ar- 
 rangement of these vessels, it is necessary to know 
 something of the peritonce'iivi. The serous mem- 
 brane, which has been spoken of as covering the 
 outside of the stomach and intestines, covers to a 
 greater or less extent all of the organs contained 
 in the abdomen, and also lines the abdominal walls. 
 This smooth, satiny membrane is called the peri- 
 tonaeum, and it renders the movements of the ab- 
 dominal organs possible without discomfort to the 
 rest of the organism. Now, the intestine being, as 
 has been shown, a long, narrow circular tube, or 
 canal, and the peritonaeum passing entirelv around 
 it, there is a line running the whole length of the 
 
 * Lactcals, from a Latin word meaning milk, because when they 
 are filled with the products of digestion they look as if they were filled 
 with milk. 
 
I04 
 
 ORGANS OF REPAIR. 
 
 intestine, where the membrane becomes double, 
 and this double fold is brought together like the 
 gathers of a dress, and attached to the spinal col- 
 umn. So the intestine is loose in the abdomen, and 
 still has an attachment to the spinal column. Be- 
 tween these two folds, or, in other words, within 
 the double fold, between the two layers of mem- 
 brane, the blood-vessels and lacteal vessels pass to 
 the intestine (Fig. 30). 
 
 Fig. 30. — Diagram representing a cross section of the small intestine, show- 
 ing the three layers, and the way in which the blood-vessels pass be- 
 tween the two folds of serous membrane (the peritonseum). 
 
 These vessels grow smaller and smaller and 
 more and more numerous as they approach the 
 intestine, and, when they at length enter its walls 
 and penetrate to the mucous membrane, they di- 
 vide into vessels so exceedingly minute as to be 
 invisible to the naked eye, and fill the interior of 
 the little projections of the mucous membrane, 
 which are called villi. 
 
 137. The Intestinal Villi. — The villi are small 
 projections on the surface of the mucous mem- 
 brane, about a thirtieth of an inch long, and thickly 
 
INTESTINAL DIGESTION. 
 
 105 
 
 covering the whole interior of the intestine, there 
 being about ten thousand of them to the square 
 inch, and about four million altogether (Fig. 31). 
 
 Each villus is covered 
 with epithelium, and in 
 its interior is a compli- 
 cated mass of blood-ves- 
 sels, twisted and knotted 
 like a bunch of earth- 
 worms (Fig. 32). In the 
 very center of the whole 
 is an open space, which 
 is the commencement of 
 a lacteal. 
 
 138. The Lacteal 
 Vessels. — The lactcals 
 are only a part of a sys- 
 
 FiG. 3i.-Section of the mucous mem- ^^^ ^£ yesscls Called the 
 brane of the small intestine, show- ' _ 
 
 ing two villi, and several secreting lympJiat' icS,\\\\\Q\\^^X,^\\^ 
 
 tubes or follicles; also lacteais, everywhere throughout 
 
 blood-vessels, and, at the bottom, , i j <t^i i 
 
 the muscular layer. ^^c body. The lym- 
 
 phatics all begin in a 
 ^ay that is not clearly understood, and gradually 
 unite to form larger and larger vessels, until their 
 contents are finally discharged into the veins and 
 mingled with the blood. The fluid found in the 
 lymphatics, called lymph, is yellowish, transparent, 
 and saltish, and, being derived from the blood, nour- 
 ishes the tissues, and takes up and carries away the 
 waste. At certain intervals in their course, the 
 lymphatic vessels are interrupted by small bodies 
 called glands,'^ varying in size from a hemp-seed to 
 
 * The lymphatic glands are the bodies that sometimes undergp 
 
io6 
 
 ORGANS OF REPAIR. 
 
 an almond, into which the vessels enter, and from 
 which they emerge. Whether they actually pass 
 through the gland, or whether 
 one vessel ends in it and another 
 begins, is still a subject of dis- 
 cussion. But the lymphatic ves- 
 sels all over the body have great 
 absorbing power, taking up in- 
 discriminately foods, poisons, or 
 the waste of used-up tissues. 
 
 The lacteals, then, are that 
 portion of the lymphatic system 
 which is connected with the 
 small intestine, and all the lac- 
 teals from the villi gradually 
 unite to form a vessel called the 
 thorac'ic duct, about as large as a 
 goose-quill, which passes up 
 close to the spine, and empties 
 into a large vein very near the 
 heart."'^ 
 
 139. The Portal Vein. — The 
 blood-vessels which absorb the food from the intes- 
 tines are veins, and they unite with the veins from 
 the stomach, pancreas, and spleen, to form one large 
 vein, called t\\Q portal vein, which enters the liver, 
 so that all the blood from the digestive apparatus 
 
 slow inflammation in persons of a scrofulous tendency, forming hard 
 lumps or abscesses in the neck. 
 
 * Many years ago, a man named Calvin Edson became extremely 
 emaciated without any known cause. He was exhibited for a long 
 time as " the living skeleton." After his death it was found that his 
 thoracic duct was completely obstructed, so that none of the contents 
 of the lacteals could pass into the blood. He died, therefore, of fat- 
 starvation— i. e., a complete or almost complete deprivation of fat. 
 
 Fig. 32. — Intestinal villus, 
 showing the epithelial 
 cells outside, the blood- 
 vessels, and the begin- 
 ning of a lacteal vessel. 
 
INTESTINAL DIGESTION. loy 
 
 passes through the liver before it enters the general 
 circulation. 
 
 140. The Chyle. — The villi, then, projecting as 
 they do into the interior of the small intestine 
 through its entire length, are continually bathed, 
 during digestion, in the nutritious fluid which other 
 organs have prepared for absorption. They float 
 and sway about in this fluid, and suck it up as the 
 roots of a tree get their sustenance from the soil," 
 and the blood-vessels probably have quite as much 
 to do in the process as the lacteals. The latter ab- 
 sorb mostly the fatty matters in the cream-like form 
 to which they have been reduced by the pancreatic 
 juice. As the walls of the vessels are thin and 
 transparent, the creamy contents, called the c/ij'/ir, 
 show through, and hence arises the white appear- 
 ance during digestion which has given them the 
 name of lacteals. 
 
 141. Changes in the Blood during Digestion. — 
 
 * The latest researches seem to show that the lacteal begins in the 
 interior of the villus as a sort of hollow space, without any special 
 wall of its own, and that around this space there are small fibers of in- 
 voluntary muscular tissue. It is believed that, during the process of ab- 
 sorption, these muscular fibers contract at regular intervals. The effect 
 of the contraction would be to pull down the top of the villus toward the 
 base, and thus diminish the size of the hollow space above referred to, 
 and empty its contents into the lacteal vessel. When the fibers relax, 
 and the hollow space expands to its original dimensions, the fluid 
 which has been forced into the lacteal is prevented from being sucked 
 back again by the valves, with which all lacteal vessels are provided. 
 The space is therefore filled again by the fluids which surround the 
 end of the villus in the intestinal canal. In this way, by the alternate 
 and regular contraction and relaxation of these minute muscular fibers, 
 the villus acts like a suction-pump, and the intestine may be looked 
 upon as lined with millions of microscopic suction-pumps, which work 
 away during digestion, pumping the contents of the intestine into the 
 lacteals, by which they are discharged into the blood. 
 
Io8 ORGAXS OF REPAIR. 
 
 As absorption goes on, the blood becomes more 
 and more loaded with fatty matters, which can 
 easily be recognized in it in the form of minute oily 
 drops, but all of this blood passes through the lungs 
 before it goes to the rest of the body. In its pas- 
 sage through the lungs, the fatty matters disappear 
 in some way, not exactly understood, and the blood 
 which comes away from the lungs contains nonCc 
 After a time, however, as digestion progresses, the 
 blood is so heavily charged with these oily matters 
 that they can not all be decomposed, and a portion 
 remains and is sent in the general circulation all 
 over the body. If blood be drawn from a man or 
 other animal at this time and allowed to stand, 
 there will be a yellowish, creamy layer on its top. 
 
 Presently, however, the fat begins to disappear, 
 as digestion approaches its close ; the amount in 
 the blood gradually diminishes, until it is entirely 
 gone, the lymph in the lacteals becomes once more 
 a transparent fluid, and digestion is complete. 
 
 142. Effect of Alcohol on the Liver. — Alcohol, 
 being absorbed by the blood-vessels of the stomach, 
 is borne away in the blood to the liver, and is 
 brought directly in contact with its structure. If 
 it is used habitually, though only in small quantities 
 at a time, the liver may become the seat of serious 
 changes. There may be a great increase of fat de- 
 posited in the cells, producing what is called by 
 physicians the '' fatty liver," or it may lead to a 
 great increase of connective tissue between the 
 cells and surrounding the blood-vessels. This new- 
 ly developed connective tissue gradually contracts, 
 and in so doing crushes the cells and obstructs the 
 blood-vessels, making the organ much smaller than 
 
INTESTINAL DIGESTION. 1C9 
 
 natural, and causing the surface to be covered with 
 little projecting knobs, consisting of portions of 
 liver-tissue that have been less compressed than the 
 part that separates them. A liver thus affected is 
 often called a " hob-nailed liver," from its appear- 
 ance, or the " gin-drinker's liver." The pressure 
 upon the liver-cells, and the destruction of many of 
 them, prevent the proper formation of bile and 
 liver-sugar. The substances composing the bile, 
 not being separated by the liver with sufficient 
 rapidity, accumulate in the blood and give rise to 
 jaundice. The contraction of the newly developed 
 tissue, by obstructing the blood-vessels, interferes 
 with the circulation. The blood is dammed back, 
 so to speak, the blood-vessels of the digestive or- 
 gans are greatly distended, and the watery part of 
 the blood oozes through the walls of the vessels 
 into the cavity of the abdomen, causing dropsy. 
 The distention of the blood-vessels of the stomach 
 is often so great that some of the more delicate 
 ones burst, and blood escapes into that organ. It 
 is turned deep brown or black by the gastric juice, 
 and produces nausea and vomiting of matters look- 
 ing like coffee-grounds. This disease of the liver, 
 called cirrhosis, is invariablv fatal. 
 
 143. General Effects of Alcohol and Tobacco 
 upon Digestion. — It will be seen from what has 
 preceded that alcohol affects more or less almost 
 every step of the digestive process. This inter- 
 ference with digestion, being in the direction of 
 preventing the normal changes in the food before 
 absorption, and also the absorptive process itself, 
 powerfully affects the nutrition of the whole body. 
 This effect is produced slowly, but is so marked as 
 
no ORGANS OF REPAIR. 
 
 to be evident in the features of the drinker. The 
 malt liquors seem to produce fatty degeneration, 
 as a rule, while the stronger liquors, whisky, etc., 
 cause the development of connective tissue. There 
 is a lack of nutrition in both cases, but in the beer- 
 drinkers the loss is masked by the growth of fat, 
 while the spirit-drinkers become emaciated. To- 
 bacco also often induces emaciation. The manner 
 in which it is used does not seem to be important. 
 Perhaps chewing interferes more with digestion, 
 on account of the great increase of saliva, and the 
 liability to swallow the tobacco-juice. The spe- 
 cial dangers attributed to cigarette-smoking are 
 probably not due so much to the quality of the 
 tobacco or the wrapper as to the cheapness of the 
 article, which leads to an inordinate consumption 
 by very young persons. 
 
 144. The Spleen. — At the left extremity of the 
 stomach, just under the ninth, tenth, and eleventh 
 ribs, is an organ which is to this da}' a great puzzle 
 to physiologists. It is called the spleen, and is about 
 five inches long, four wide, and an inch thick. It 
 is reddish in color, soft and pulpy in texture, with 
 a very tough and strong fibrous covering. It re- 
 ceives its blood from a very large arter}^ and its 
 vein, which carries away the blood from the organ, 
 joins the portal vein, so that the blood from the 
 spleen, like that from the other organs of digestion, 
 passes through the liver, before it reaches the heart. 
 The spleen is large in well-fed animals, and very 
 small and shrunken in starved ones, while in some 
 cases of disease, such as fever and ague, it reaches 
 the enormous weight of twenty pounds, and forms 
 an immense hard tumor in the left side. 
 
INTESTINAL DIGESTION, m 
 
 The facts just stated would seem to imply that 
 the spleen has some important office to perform in 
 digestion, but what that office is no one has been 
 able to discover.^ It is a singular fact that the 
 spleen may be entirely removed without permanent 
 injur}^ to the health. It has been several times re- 
 moved from human beings, on account of disease. 
 The effect upon them, although not so pronounced, 
 is of the same character as the effect upon the lower 
 animals, which show an enormous increase of appe- 
 tite, usually gain considerable flesh, and acquire an 
 unnatural ferocity of disposition. These things, 
 however, do not seem to indicate that any particu- 
 lar function has been lost to the body, and the uses 
 of the spleen are still a subject of earnest investi- 
 gation. 
 
 * The most reasonable theory about the spleen at present seems to 
 be that it has something to do with the destniction of old and worn-out 
 blood-corpuscles and the formation of new ones. 
 
CHAPTER VI. 
 
 THE BLOOD. 
 
 145. The Blood. — After the nutritious portions 
 of the food have been taken into the blood, they 
 pass through the lungs before they go into the 
 general circulation. Before we consider the respi- 
 ration, however, it is necessary to know something 
 of the circulating fluid. 
 
 The blood is a thick, opaque fluid, varying in 
 color in different parts of the body from a bright 
 scarlet to a dark purple or even almost black. It 
 has a somewhat viscid feel, a faint odor peculiar to 
 itself, and a saltish taste. 
 
 146. The Red Blood-Corpuscles. — If a drop of 
 blood be placed under the microscope,^ immense 
 numbers of small bodies will be seen, which are 
 called the blood-corpuscles (Figs. 33 and 34). They 
 are very minute, averaging only -g-^Vo ^^ ^^ inch in 
 diameter, and are flattened in their shape. They 
 may be described as looking like a cylindrical ring, 
 the center of which has been filled up, but not quite 
 to the level of the border, so that there is a slight 
 depression on each flattened side. Taken singly, 
 
 * Prick the end of the finger with a pin. The most minute drop 
 of blood is sufficient. Put it on a glass slide under a thin glass cover, 
 and place it under a microscope. 
 
THE BLOOD. 
 
 113 
 
 these bodies, called the red blood-corpuscles, are of a 
 light amber color, but in a large mass they give 
 
 the characteristic red col- 
 or to the blood. They vary 
 somewhat in size in differ- 
 ent animals, those of the 
 monkey approaching most 
 nearly to those of the hu- 
 man being. In birds, rep- 
 tiles, and fish, they are 
 very much larger, and in- 
 stead of being circular are 
 oval (Fig. 35).* They also 
 have a distinct nucleus. 
 It is mainly by these microscopical differences that 
 the blood of different animals can be distinguished 
 
 Fig. 33. — Human blood-corpuscles, 
 including two white ones. 
 
 Fig. 34. — Human blood-corpuscles (highly magnified). From a photograph. 
 
 *•■ The blood-corpuscles of the camel tribe are also oval, but smaller 
 than those of birds. 
 
114 
 
 ORGANS OF REPAIR. 
 
 WHITE 
 
 Fig. 35. 
 
 Blood-corpuscles of the 
 frog. 
 
 from that of man, as is sometimes necessary in 
 trials for murder. 
 
 147. The White Blood-CorpuscleSo— The blood 
 also contains white corpus- 
 cles in the proportion of one 
 white corpuscle to three 
 hundred red ones. They 
 are larger than the red, are 
 perfectly colorless, and glo- 
 bular in their form. The 
 white corpuscles, under 
 proper conditions, are seen 
 to be continually changing 
 their form, almost like liv- 
 ing animals. There have 
 been many speculations as 
 
 to their office in the body, but nothing definite has 
 been ascertained. In certain diseases, however, 
 they are found to increase enormously in number, 
 and some of these diseases are among the most 
 dangerous and difficult to treat of any the physi- 
 cian meets with. 
 
 Although the blood-corpuscles are so very mi- 
 nute, they exist in such enormous numbers that 
 they are estimated to compose half the mass of 
 the blood. 
 
 148. The Plasma, — The fluid portion of the 
 blood, in which these small bodies float, is called 
 th.Q plasma. It is almost colorless, quite transpar- 
 ent, and is nine tenths water. Its two most im- 
 portant ingredients are albumen and fibrin.'^ The 
 
 * It is now believed that fibrin does not exist, as such, in fluid 
 blood, but that there are certain substances (known as fibrino-plastin 
 or paraglobztlin, fibrinogen, and fibrin-ferment) which, by their inter- 
 
THE BLOOD. II5 
 
 former of these is chiefly concerned in nutrition, 
 and the latter brings about the remarkable phe- 
 nomenon known as coagulation. The plasma also 
 contains various compounds of lime, soda, mag- 
 nesia, etc., which have their own functions to per- 
 form in the nourishment of the body. 
 
 149. Coagulation of the Blood. — If blood be 
 drawn from the living body, it very soon under- 
 goes coagulation. This is due to its fibrin (or fibrin- 
 factors) ; but the cause of the change is very im- 
 perfectly understood. After the blood has stood 
 for a few minutes outside the blood-vessels, it at 
 first becomes less fluid and assumes somewhat the 
 appearance of jelly. Shortly the fibrin begins to 
 contract and occupy a smaller space, gradually 
 squeezing out the portion of the blood which still 
 remains fluid. This mass which separates from the 
 rest of the blood is called the clot, and the remainder, 
 or still fluid portion, is called the scrum. The con- 
 traction of the clot continues for several hours, 
 until it forms quite a firm mass of a deep-red color, 
 the remaining fluid being transparent and nearly 
 colorless. 
 
 The red color of the clot is due to the fact that 
 the red corpuscles become entangled in the coagu- 
 lated fibrin, and, being semi-solid in consistency, 
 they remain there and are not pressed out with the 
 serum. It will be noticed that the scrum is not the 
 same as the plasma. The latter includes the fibrin 
 (or fibrin-factors\ while the former is without it. 
 
 150. Coagulation under Varying Conditions. — It 
 is found that the blood coagulates more rapidly in 
 
 action, produce fibrin, and so cause coagulation. The evidence foi 
 this view is of too abstruse a nature to be given here. 
 
II6 ORGANS OF REPAIR. 
 
 thin layers than in a large mass ; in a vessel or on a 
 surface which is rough than in one which is smooth. 
 For this reason the blood flows longer from a 
 smooth cut in the body than from a wound with 
 torn and ragged edges. In the latter case the blood 
 coagulates very rapidly and stops the hemorrhage. 
 
 But the coagulation of the blood takes place not 
 only outside the body, but, under similar circum- 
 stances, inside, though not always with equal ra- 
 pidity. If a vessel bursts inside the body, and 
 blood escapes into the tissues around it, coagula- 
 tion takes place after a short time ; and this occurs 
 even inside the blood-vessels, if there be any ob- 
 struction to the circulation. If an artery or vein 
 be compressed by a string or wire or finger, the 
 blood will soon coagulate in the vicinity of the 
 pressure. These facts have suggested the means 
 used by surgeons to stop the flow from a bleeding 
 wound, and will be referred to again. 
 
 151. Total Amount of Blood. — The total ainoimt 
 of blood in the human body is believed to be about 
 (me twelfth of the zvJiole weight of the individual. 
 Thus, in a man who weighs one hundred and fifty 
 pounds there will be about thirteen pounds of blood, 
 or somewhat more than a gallon and a half. 
 
 152. Oxygen in the Blood. — This rich, nutritious 
 fluid is forced to all parts of the body in a way here- 
 after to be described, carrying food to exhausted 
 tissues and removing the used-up matters. A large 
 part of the material necessary for the growth and 
 nourishment of the body is taken in through the 
 digestive organs ; but there is a gas absorbed by 
 the blood, in its passage through the lungs, which 
 is even more necessary to life than food. This gas 
 
THE BLOOD. II7 
 
 is oxygen, which coPxStitutes about one fifth of the 
 atmosphere, and is essential to the hfe of all animals, 
 probably without exception. We can live for days 
 without food, but we can not live ten minutes with- 
 out oxygen. Even water-animals are not exempt 
 from this law ; for fish extract the air, which is in 
 solution in the water, by passing it through their 
 gills. If a dish of water containing a fish be placed 
 under the receiver of an air-pump, and the air be 
 exhausted from it, the fish will be as surely drowned 
 as a man would be if held under water. This is the 
 reason why fish which are kept as pets in aquaria 
 need fresh water continually. If a jet of water be 
 kept falling into the vessel in which they live, so as 
 to drag down bubbles of air, the water need never 
 be changed, except for cleanliness. 
 
 153. Varying Color of the Blood. — The blood 
 which enters the lungs is very dark, and sometimes 
 almost black. AVhen it has passed through the 
 lungs, and flows away, it is of a bright scarlet. It 
 has lost certain substances and gained others during 
 this passage, and this beautiful and surprising alter- 
 ation is produced by what is called the process of 
 respiration. 
 
 154. Effect of Alcohol and Tobacco on the 
 Blood. — Alcohol increases the amount of fat in the 
 blood, exactly how is not known. It also lessens 
 the capacitv of the blood to absorb oxygen, and in 
 this way interferes with the nutrition of the body. 
 Tobacco is said to hinder the development of the 
 red corpuscles, and in this way the pallor that so 
 often accompanies the excessive use of tobacco is 
 accounted for by some ; this, however, has not been 
 decidedly proved. 
 
 9 
 
CHAPTER VIL 
 
 RESPIRATION. 
 
 155. Respiration a Complicated Process. — At 
 
 first sight, the process of respiration is a very sim- 
 ple one, consisting merely in the inspiration and 
 expiration of air. In reality, however, it is compli- 
 cated — certain very essential parts of it going on 
 without our consciousness, like so many of the phe- 
 nomena of digestion. The organs mainly concerned 
 in the acts of respiration are the lungs ; but there 
 are certain additional organs, whose functions, if not 
 absolutely necessary, are certainly important. 
 
 156. The Nasal Passages, — The air, before 
 reaching the lungs, goes through several passages, 
 lined throughout with mucous mxcmbrane. The 
 human being can breathe through either the nose 
 or the mouth ; but in some animals (the horse, for 
 instance) respiration only takes place through the 
 nose, and, if this be closed, suffocation follows. The 
 external openings of the nose are guarded by short, 
 stiff hairs, which grow just inside the nostrils, and 
 which serve to purify the air somewhat, as it passes 
 through them, by catching and retaining particles 
 of dust. The interior of the nose is so formed that 
 it is not a large, open, free passage, but has a num> 
 ber of projecting bones, running lengthwise along 
 
RESPIRA TION. 1 1 9 
 
 its walls, which are covered with moist membrane 
 and present an extensive mucous surface to attract 
 particles from the air. If we breathe through the 
 mouth, on the other hand, the air goes directly to 
 the throat, and the cavity of the mouth is so large 
 that the purifying effect of the moist membrane is 
 hardly perceived. This shows how much better it 
 is to breathe always through the nose ; for the air, 
 undoubtedly, in this way, is rid of many impurities ; 
 and physicians habitually, and almost unconsciously 
 to themselves, keep their mouths shut as much as 
 possible when they are exposed to a contagious 
 disease. 
 
 From the nose the air arrives at the throat, and 
 thence it passes into the windpipe, or trachea, 
 through a small opening called the glottis. 
 
 157. The Trachea. — The tra'cJica (Fig. 36) is a 
 tube about four and a half inches long and an inch 
 wide, which divides at its lower extremitv into two 
 smaller tubes called broncJii^ one of which goes to 
 each lung. It is mainly fibrous in its structure, 
 and it is kept open to its full extent by a number 
 of rings of cartilage, placed at a short distance 
 apart through its whole length. The trachea is 
 situated in the neck just in front of the oesophagus, 
 and as these stiff rings might press backward on 
 the oesophagus, and thus interfere with the process 
 of swallowing, they do not pass completely around 
 the trachea, but are lacking in the part next the 
 oesophagus, comprising about one third of the 
 whole circumference of the tube. At the upper 
 extremity of the trachea is the lar'yiix, or the organ 
 of voice, w^hich is essentially a triangular-shaped 
 box of cartilage, the lower end opening freely into 
 
I20 
 
 ORGANS OF REPAIR. 
 
 the trachea, and the upper being closed by muscles 
 and membranous tissues, with the exception of the 
 opening of the glottis. 
 
 Fig. 36.— Larynx, trachea, and bronchi, showing; the manner of division, 
 and the rines of cartilage. 
 
 158. The Glottis. — The glottis is a slit-shaped 
 opening, a little less than an inch long, extending 
 from before backward and from above downward, 
 
RESPIRATION. 12 1 
 
 not being, in other words, either perpendicular or 
 horizontal in the throat, but shelving toward the 
 rear. The front extremity is at the base and back 
 of the tongue, and the opening itself is bounded at 
 the sides by two firm, fibrous, strong, pearly- white 
 membranes, called the vocal chords, by the vibration 
 of which sound is produced. These vocal chords 
 can be separated to the extent of half an inch, or 
 brought together so as to touch, by the muscles 
 which are attached to the back part of the larynx. 
 The production and modulation of the voice will 
 be treated of hereafter. 
 
 At the base of the tongue, springmg upward 
 just above the forward end of the glottis, is a stiff 
 piece of cartilage, shaped like a leaf with a rounded 
 end. This is called the epiglottis, and probably 
 performs two functions, viz., that of protecting the 
 glottis from food or other substances during the 
 act of swallowing, and that of directing the column 
 of expired air up toward the roof of the mouth 
 or throat, and so aiding in the modulation of the 
 voice. 
 
 159. The Lungs. — The essential organs of res- 
 piration are the lungs, which are two in number and 
 fill nearly the whole cavity of the chest, a portion, 
 however, being occupied by the heart and large 
 blood-vessels. The lungs are very light in propor- 
 tion to their size, and in animals they are common- 
 ly called " the lights." They weigh together only 
 about two pounds and a half, and easily float in 
 water. In small children they are of a beautiful 
 pinkish color, but in older persons they become 
 slate-colored, and have black spots scattered here 
 and there over their surface. 
 
122 
 
 ORGANS OF REPAIR. 
 
 Fig. 37. — Section of 
 a pulmonary lob- 
 ule, showing its 
 division into pul- 
 monary vesicles. 
 
 160. Minute Divisions of the Lungs. — After the 
 trachea divides into two bronchial tubes, one of 
 which goes to each lung, these bron- 
 chial tubes continue to subdivide in- 
 to smaller and smaller tubes, all the 
 branches diverging widely from 
 each other, until their diameter is 
 diminished to about -^-^ of an inch. 
 At about this point the cartilage 
 rings disappear, but the tubes still 
 divide until the smallest are only -^ 
 of an inch in diameter. At the very 
 ends of the smallest tubes, there is 
 an enlargement about -^ of an inch 
 in diameter, called a pulmonary lobule 
 (Fig. 37). It constitutes a small cav- 
 ity, into which dip little partitions, that do not meet 
 each other, but create minute hollow spaces around 
 the sides of the lobule, called pulmonary 
 vesicles. These are about -^ of an inch 
 in diameter, and are the smallest divis- 
 ions of the lung. 
 
 161. The Lining Membrane of the 
 Lungs. — All these tubes and passages, 
 down to the most minute, are lined 
 Avith a delicate mucous membrane, 
 which has this remarkable peculiarity. 
 The little epithelial cells with which all 
 mucous membranes are covered, have 
 in this situation what are called cilia at 
 their ends (Fig. 38). That is to say, 
 each cell has at its tip a fine, hair-like 
 lash, which keeps in constant motion, 
 the person lives, and for some time 
 
 Fig. 38.— Cilia- 
 ted epithelium 
 from a small 
 bronchial tube. 
 1 he small 
 
 round cells at 
 the bottom are 
 young ones. 
 
 as long as 
 
RESPIRATION. 123 
 
 after he is dead. If a piece of the mucous mem- 
 brane from the throat of a frog just killed be 
 snipped off with a pair of scissors and placed under 
 the microscope, this incessant motion of the cilia 
 may be easily seen. Although they are so delicate 
 in their structure, they are so innumerable and act 
 in such perfect concert, that they keep up a con- 
 stant current toward the outside of the body. 
 They probably aid in the expulsion of the foul 
 gases which the blood leaves in the lungs. 
 
 162. Effect of Alcohol and Tobacco on the Nose 
 and Throat. — The habitual use of alcoholic drinks 
 often results in a chronic catarrh of the throat 
 and nose. The membrane becomes red, swollen, 
 streaked with enlai-ged veins and covered with 
 stringy mucus, which the drinker is constantl}^ try- 
 ing to get rid of by hawking and spitting. This 
 chronic inflamed condition of the throat produces 
 almost constant thirst, generally gratified by more 
 alcohol, which keeps up the irritation it is meant 
 to soothe. This inflammation often involves the 
 vocal chords, giving rise to the well-known husky 
 voice of the old toper. 
 
 Much the same condition of the nose and throat 
 is brought about by smoking tobacco, the smoke 
 constantly irritating the mucous membrane of the 
 throat and nose, and producing chronic catarrh of 
 those parts. It is said that no habitual smoker has 
 a healthy throat. 
 
 The excessive secretion of saliva in those who 
 chew tobacco produces extreme thirst, and may 
 thus lead to the habitual use of alcoholic liquors. 
 
 163. Effect of Alcohol upon the Lungs. — The 
 effect of alcohol upon the lungs of habitual drinkers 
 
124 
 
 ORGANS OF REPAIR, 
 
 is very marked. The mucous membrane becomes 
 congested and the secretion of mucus more plenti- 
 fuL Colds are easily contracted and hard to get 
 rid ofj and a chronic bronchitis results. This finally- 
 diminishes the elasticity of the lung tissue, and the 
 air-vesicles become in spots permanently distended 
 like little bladderSo The function of respiration is 
 thus interfered with, and the sufferer becomes short 
 of breath, often asthmatic, is troubled with a con- 
 stant cough and hawking of mucus, so that his life 
 is a burdeuo 
 
 Alcohol, instead of preventing consumption, as 
 was once believed, reduces the vitality so much as 
 to render the system unusually susceptible to that 
 fatal disease. 
 
 164. Asthma. — The smaller bronchial tubes, 
 which have no rings of cartilage, are nevertheless 
 surrounded by involuntary muscular fibers. When, 
 in consequence of disease, these fibers contract 
 strongly, they diminish the caliber of the tubes, and 
 render it very difficult sometimes for the sufferer 
 to get air through them in either direction. This 
 condition gives rise to great distress and a sense 
 of suffocation, and is called astJnna. 
 
 1650 The Blood- Vessels of the Lungs. — Between 
 the pulmonary vesicles run the small blood-vessels 
 immediately under the delicate mucous membrane, 
 so that the blood comes almost in contact with the 
 air that we breathe. They surround the vesicles com- 
 pletely, and it is in this part of the lung that the great 
 changes take place in the blood during respiration. 
 
 166. The Outer Covering of the Lungs. — The 
 outside of the lung is covered by serous membrane, 
 and so is the inside of the chest-walL This renders 
 
R ESP IRA TION. 
 
 \2 
 
 the movements of the lung painless and easy. This 
 membrane is called th.Q pleura, and when it becomes 
 inflamed, in the disease known as pleurisy, respira- 
 tion becomes excessively painful. 
 
 167. Inspiration. — As the cavity of the chest is 
 enlarged, the air already in the lungs is rarefied, 
 and the external atmospheric pressure forces air 
 in to fill the organs. We have already stated that 
 the ribs are so shaped, and so connected with the 
 spine behind and the sternum in front, that when 
 they are raised up toward the shoulders the sides 
 move outward, and the sternum moves forward. 
 This motion of the ribs is caused partly by power- 
 ful muscles attached to 
 their external surface all 
 the way down the chest, 
 and partly by short mus- 
 cles which pass between 
 the ribs from the lower 
 edge of each one to the 
 upper edge of the one 
 just below it. 
 
 But, in addition to its 
 expansion toward the 
 front and sides, the cav- 
 ity of the chest is en- 
 larged in a downward 
 direction by the con- 
 traction of the diaphragm 
 (Fig. 39). This muscle 
 has a strong, flat, ten- 
 dinous center, from every side of which strong 
 muscular fibers pass to the walls of the chest. It 
 separates the chest from the abdomen, and while 
 
 Fig. 39. — Diagram illustrating the vary- 
 ing position of the diaphragm during 
 respiration. 
 
126 ORGANS OF REPAIR. 
 
 the muscular portion of it is attached to the lower 
 ribs, the spine and the very end of the breastbone, 
 the center rises much higher in the chest, so that 
 it has the shape of a vaulted roof, on top of which 
 are the lungs and heart, and underneath the stom- 
 ach and liver. Of course there are passages through 
 it for the blood-vessels and nerves, but these open- 
 ings are so guarded that the diaphragm forms a 
 tight partition. Now, as the center of the diaphram 
 rises so much higher than the sides, it is very evi- 
 dent that a contraction of the muscular fibers will 
 pull the center downward, and so increase the ca- 
 pacity of the chest. And this is what actually 
 occurs at every inspiration. When this contrac- 
 tion takes place spasmodically, the air is drawn 
 into the lungs with a sudden impulse, and we call 
 it hiccough!^ 
 
 i68. Expiration. — Inspiration then involves a 
 contraction of many muscles, and they act with a 
 great deal of force, for they have to lift the atmos- 
 phere, which is pressing on the outside of the 
 chest with a force of fifteen pounds to the square 
 inch. By this simultaneous contraction, the ribs 
 are drawn out of their natural position — i. e., they 
 are drawn upward into a position which they never 
 would assume if left to themselves. By the elastici- 
 ty of their cartilages and other tissues attached to 
 them, they tend to return to their former position 
 as soon as the force which has drawn them out of 
 
 * Hiccough, being due to a spasmodic action of the diaphragm, may 
 be stopped by any means that tends to control the spasm. The easiest 
 method is to put the diaphragm on the stretch, as follows : prolong the 
 act of expiration as much as possible, and at the end make a forcible 
 expiration ; then inspire slowly and take as full an inspiration as pos- 
 sible. It is rare that a second trial will be necessary. 
 
RESPIRATION, 12; 
 
 it ceases. The diaphragm, also, when contraction 
 stops, tends to recover its former arched shape. 
 The lungs also contain, in addition to the elements 
 already mentioned, a large amount of elastic fibers, 
 interlaced with the other tissues in every direction. 
 These, too, as soon as the pressure which has 
 stretched them ceases, tend to return to their for- 
 mer condition. This elasticity of the different 
 organs concerned in the act of respiration, then, 
 brings the chest and lungs back to the condition in 
 which they were before inspiration began. This 
 is the ordinary act of expiration. 
 
 169. Relative Force of Inspiration and Expira- 
 tion. — As we usually breathe, then, the act of inspi- 
 ration is an active one, requiring effort and power- 
 ful muscular contraction, while the act of expira- 
 tion is passive, and is accomplished by the elasticity 
 of the tissues." 
 
 Under other conditions, however, the act of 
 expiration may be more powerful than that of in- 
 spiration. There are strong muscles connected 
 with the chest in such a way as to act in opposition 
 to the muscles of inspiration, and make the cavity 
 of the chest smaller than it ordinarily is. It is by 
 the active contraction of these muscles that we pro- 
 duce what is called a forced expiration, which has 
 been estimated by careful observers to be one third 
 more powerful than a forced inspiration. 
 
 170. Amount of Air respired with Each Breath. 
 
 * The outer surface of the kings is kept in contact with the chest- 
 walls by atmospheric pressure. If the chest-wall be punctured, so 
 that the air-pressure is the same both outside and inside of the lung, 
 the elasticity of the organ is such that it immediately collapses, driving 
 out all the air from its interior. 
 
128 ORGANS OF REPAIR. 
 
 — The amouTit of air taken into the lungs with each 
 inspiration is about twenty cubic inches. Now, the 
 entire capacity of the lungs varies in different per- 
 sons from one hundred and fifty to two hundred 
 and fifty cubic inches or even more. So that with 
 each breath, a very small amount, generally not 
 one tenth, of the air in the lungs is changed. It is 
 even estimated that after the most forcible expira- 
 tion possible, at least one hundred cubic inches of 
 air will remain in the chest of a man of medium 
 size, which can not be expelled. In ordinary breath- 
 ing, therefore, only the air in the larger bronchial 
 tubes can pass in and out of the lungs. But the 
 changes in the blood must be produced at the ex- 
 treme end of the finest tubes in the pulmonary 
 vesicles. So the question arises. How does the air 
 get to the vesicles ? 
 
 171. How the Air in the Lungs is changed. — In 
 the Ji7'st place, the law of the diffusion of gases comes 
 in play. When two gases come together, they tend 
 to mingle with each other until they finally occupy 
 equally the whole of the vessel or other confined 
 space in which they may be. After the mixture, 
 each gas will be found in the same proportion in 
 every part of the vessel. Now, the air in the pul- 
 monary vesicles and smallest bronchial tubes is 
 heavily loaded with carbon dioxide (carbonic acid), 
 while that which is drawn in with inspiration is rich 
 in oxygen. These two gases, then, carbon dioxide 
 and oxygen, are constantly being diffused through- 
 out the whole of the lungs. In the second place, 
 the cilia, which have already been described, being 
 in constant motion, keep up a current of the foul 
 air from the pulmonary vesicles along toward the 
 
RESPIRATION. 1 29 
 
 larger bronchi and trachea, and fresher air keeps 
 constantly pressing in to fill the place of what has 
 been in this way removed. Thus, in the smallest 
 bronchial tubes, there are always two currents of air 
 passing each other in opposite directions : one, im- 
 mediately next the mucous membrane, being a thm 
 layer moving outward ; and the other, in the center 
 of the tube, moving inward (Fig. 40). So that the 
 air in the larger bronchi and trachea is changed 
 periodically by the acts of 
 inspiration and expiration, 
 w^hile the circulation of 
 the air in the small bron- _^ 
 
 Chial tubes and pulmonary Fig. 40.— imaginary section of a 
 
 vesicles is continuous. ^"^^^^ bronchial tube, showing 
 
 i. r A • ^^ influf^nce of the ciHa in pro- 
 
 172. Amount of Air re- ducing an outward current of air. 
 
 spired daily. — The amount 
 
 of air taken in with every inspiration is about twen- 
 ty cubic inches. The average number of respira- 
 tions per minute is eighteen. This is a matter 
 which varies very much with the individual. Chil- 
 dren and women breathe somewhat more rapid- 
 ly than men ; but taking eighteen as the average, 
 the quantity of air breathed per minute is three hun- 
 dred and sixty cubic inches, or about one fifth of a 
 cubic foot. In an hour, then, we use about twelve 
 cubic feet of air, and in a day nearly three hun- 
 dred cubic feet. This amount is increased by every 
 muscular exertion, and also by the curious tact that 
 the ordinary respiration does not seem to be alto- 
 gether sufficient for the needs of the body, and every 
 now and then we draw a deeper breath than the 
 average. This occurs usually about once in every 
 five or six acts of respiration. Considering the in- 
 
I30 
 
 ORGANS OF REPAIR. 
 
 crease in the amount of air respired at each long 
 breath, and the increase of rapidity of respiration 
 due to shght causes during the day, it is estimated 
 that an adult really respires about three hundred 
 and fifty cubic feet of air per day. 
 
 173. Changes produced in the Air by Respira- 
 tiono — When the air enters the lungs it contains 
 nearly 21 per cent of oxygejt and 79 per cent of 7ti- 
 trogeuj with about one twentieth of one per cent ol 
 carbon dioxide^ a little watery vapor ^ and a trace ol 
 ammonia. 
 
 If the air be collected at expiration, after having 
 undergone the changes in the lungs, we find the 
 following : 
 
 lo It has lost oxygen. 
 
 2. It has gained carbon dioxide, 
 
 3. It contains more watery vapor. 
 
 The watery vapor in the expired air is not or- 
 dinarily visible, but in cold weather, when it be- 
 comes condensed, it can be very plainly seen. The 
 whole amount of water passed away daily in the 
 breath of a man has been carefully estimated, and 
 found to average about one and one sixth pound 
 avoirdupois. 
 
 174. Former Theory about the Formation of 
 Carbon Dioxide. — Out of the four cubic inches of 
 oxygen taken into the lungs with each inspira- 
 tion, one cubic inch disappears. The carbon dioxide 
 which is exhaled from the lungs consists of carbon 
 and oxygen united in certain proportions, and it 
 used to be supposed that the carbon in the blood 
 united with the oxygen of the air in the lungs 
 themselves, forming carbon dioxide, and that in 
 this way the carbon, released by the wear and tear 
 
RESPIRATION. 131 
 
 of the body, was got rid of. Now, the process of 
 combustion in a flame of any kind consists in this 
 same change, viz., the union of the carbon and hy- 
 drogen of the oil or other inflammable substance 
 with the oxygen of the surrounding air, forming 
 carbon dioxide and water, and giving out heat 
 during the process. So it was for a long time 
 thought that the lungs were a sort of furnace in the 
 body, where the carbon and hydrogen of the blood 
 were burned, so to speak, and the products of com- 
 bustion exhaled, while the heat occasioned by the 
 process kept up the warmth of the body. This was 
 a beautiful theory, but it is found not to be warrant- 
 ed by the facts. 
 
 There is more oxygen absorbed in the lungs, with 
 every respiration, tJian is exhaled in the carbon di- 
 oxide and watery vapor taken together. This fact 
 of itself disproves the above theory, for it shows 
 that a portion of the oxygen disappears in the 
 lungs, or is carried away by the blood. 
 
 175. Organic Matter in the Breath. — Besides 
 the carbon dioxide given off in the expired air, 
 there is a certain amount of organic matter, con- 
 taining nitrogen, which gives the breath a slight 
 but peculiar odor. Where many persons are 
 breathing in a badly ventilated room, this organic 
 matter accumulates, and imparts to the atmosphere 
 that odor which we all recognize as peculiarly op- 
 pressive and close. 
 
 176. Changes in the Blood during Respiration. 
 — The blood undergoes changes in its passage 
 through the lungs which correspond to the changes 
 in the air. In the first place, it is altered in its 
 color. As it enters the lungs, it is of a deep bluish 
 
132 ORGANS OF REPAIR. 
 
 purple, almost black ; as it emerges, it is of a beau- 
 tiful and most brilliant scarlet. On chemical ex- 
 amination, to determine the cause of this remark- 
 able change, it is found that the blood which comes 
 away from the lungs contains more oxygen and 
 less carbon dioxide than that which enters them. 
 Additional proofs that the formation of carbon di- 
 oxide does not take place by direct combination 
 in the lungs are the facts that the venous blood, 
 before it enters the lungs, is deeply charged with 
 carbon dioxide already formed, and that the blood 
 which comes away from the lungs contains oxygen 
 in free solution. 
 
 The brilliant color, which is the result of this 
 change in the blood, has not yet been satisfactorily 
 accounted for. It has been proved that the oxy- 
 gen and carbon dioxide are carried by the blood- 
 corpuscles, and not by the plasma, and the change 
 of color in the blood is entirely due to the change 
 in those minute bodies. They have been said to 
 change their shape and become more globular in 
 one case than in the other, but the attempts to ex- 
 plain the difference of color have not yet been en- 
 tirely successful.* 
 
 177. Where the Carbon Dioxide is formed. — If 
 the carbon dioxide is not formed in the lungs, 
 then where does it come from ? Experiments of 
 the most ingenious kind have been performed to 
 determine this question, and they are too long to 
 
 * The coloring-matter of the red corpuscles is called hemoglobin. 
 It is found that this substance, when united with an excess of oxygen, 
 forming oxyhgemoglobin, has a bright scarlet color, and, when the 
 amount of oxygen is greatly reduced, is of a dark purple. But this 
 does not explain much. 
 
K ESP IRA TION. 
 
 133 
 
 mention in detail. But it has been conclusively 
 shown that most of the carbon dioxide is formed 
 in the tissues in all parts of the body, during the 
 processes of nutrition. And even here it is not 
 produced by a direct combination of the oxygen 
 with the carbon, for the exhalation of carbon di- 
 oxide will continue for a considerable time in an 
 atmosphere of hydrogen, where of course there is 
 no oxvijen furnished to the tissues. The carbon 
 dioxide, then, is formed by decomposition of the 
 tissues, and the oxygen is used by them to build 
 themselves up again. "^ The amount of carbon di- 
 oxide given off in the breath has been found to be 
 somewhat less than one cubic inch, or about four- 
 teen cubic feet per day, weighing about a pound 
 and a half, and representing waste of the organism 
 to about this amount. 
 
 178. Effect of Alcohol and Opium on the Func- 
 tion of Respiration. — Although the evidence is con- 
 flicting, it is now generally conceded that alcohol 
 diminishes the excretion of carbon dioxide and 
 watery vapor from the lungs. Opium has the same 
 effect. It is probabh' the result of diminished activ- 
 ity of the cells, due directly to the paralyzing effect 
 of these drugs. 
 
 Opium lessens the frequencv of respiration and 
 renders the throat and mouth dry by diminishing 
 the secretion of mucus. In fact, it diminishes all 
 the secretions of the bod}^ excepting the perspira- 
 tion, which is increased by it. 
 
 179. Composition of Air.— Air being so essential 
 
 * It will be understood that the place of the carbon which is lost to 
 the body in the carbon dioxide which passes off by the lungs, is sup- 
 plied by the fresh material taken in with the food. 
 10 
 
134 
 
 ORGANS OF REPAIR, 
 
 to life, it is evidently important to have it as pure as 
 possible. It must contain enough oxygen, so that 
 with each respiration the temporary needs of the 
 body may be satisfied, and should contain no sub- 
 stances which are injurious to life or health. Now, 
 the air normally contains about four parts of nitrogen 
 to one of oxygen, and the variation in the amount 
 of these constituents is found to be surprisingly 
 small in widely different localities.''^ It always con- 
 tains a small amount of carbon dioxide, and a varia- 
 ble quantity of watery vapor. f It is also never found 
 
 * The following analyses, mostly by Mr. Angus Smith, show this 
 very clearly : 
 
 Locality whence air wan taken. Percentage of oxygen. 
 
 Middle of Hyde Park, London 21.005 
 
 Sea-shore and heath, Scotland 20.999 
 
 Tops of hills, Scotland 20.98 
 
 Forests, Scotland 20.97 
 
 Summit of Mt. Blanc 20.963 
 
 London, open parts, summer. . , 20.95 
 
 Bottom of hills, Scotland 20.94 
 
 Open parts of Glasgow 20.929 
 
 Marshy places 20.922 
 
 Chamonix, Switzerland 20.894 
 
 Sitting-room, feels close 20.89 
 
 Air procured from balloon i8,O0O feet high 20.88 
 
 Theatre gallery, 10.30 P. M 20.86 
 
 In small room, kerosene-lamp burning 20.84 
 
 In small room, after six hours 20.83 
 
 Theatre pit, 11.30 p. M. 20.74 
 
 Closer parts of Glasgow 20.706 
 
 Mines, under shafts, average of many 20.42 
 
 Mines where candles go out 18.50 
 
 Very difficult to remain in . 17.20 
 
 f This watery vapor is a very necessary constituent of the air. Out- 
 of-doors the amount of it is regulated in ways beyond our control ; 
 but in-doors, unless special care is taken, the air may be so dried by 
 artificial heat, that when respired it will absorb more than the ordinary 
 amount of moisture from the mucous lining of the lungs. Then the 
 
RESPIRA TION. 
 
 135 
 
 entirely free from impurities, such as other gases 
 than those named, in small quantity, and minute 
 floating particles of matter, which we group to- 
 gether under the common naniie of dust. 
 
 It has been shown, however, that the breathing 
 of animals is continually removing ox3'gen from the 
 air and increasing the amount of carbon dioxide. 
 Now, carbon dioxide is a poison to animals, and 
 if inhaled in large amount produces almost imme- 
 diate unconsciousness and death. It is for this rea- 
 son that it is being constantly rejected from the 
 body. If this process of removing oxygen from 
 the air and adding carbon dioxide to it were to 
 go on indefinitely, it is evident that after a time 
 the one would be so much reduced in amount, 
 and the other so much increased, that animals 
 would die of carbon-dioxide poisoning — i. e., of 
 asphyxia. 
 
 180. Respiration of Plants. — This danger is 
 guarded against in the outer atmosphere by the 
 constant absorption of carbon dioxide bv plants. 
 All plants, through their leaves, decompose car- 
 bon dioxide into its original parts, carbon and 
 oxygen. The carbon they appropriate for their own 
 nourishment, and the oxygen they return to the at- 
 mosphere. Thus the respiration of plants is exactly 
 the reverse of that of animals. The latter absorb 
 oxygen and give out carbon dioxide, and the for- 
 mer absorb carbon dioxide and give out oxygen. 
 
 mucous membrane becomes diy, there is an increased flow of blood to 
 the part, and, if the dnness of the air is not remedied, inflammation 
 may result — i. e., a catarrh. For this reason a vessel of water should 
 always be kept on the top of a heated stove or furnace, that its evapo- 
 ration may insure suflicicnt moioture in the air to prevent injury to the 
 lungs and throat. 
 
136 ORGANS OF REPAIR. 
 
 By this never-ending interchange the proportions 
 of oxygen and carbon dioxide in the atmosphere 
 are kept about the same. 
 
 181. Contamination of the Air in HouseSo— In- 
 doors, however, there is no opportunity for this 
 self-purification. Even if a few plants are kept in 
 the house, the amount of carbon dioxide they con- 
 sume is very little, and the effect they are able to 
 produce toward purifying the room can not be com- 
 pared with that of the immense stretches of forest 
 and plain out-of-doors. Moreover, the amount of 
 carbon dioxide in houses is increased by combus- 
 tion. A five-foot gas-burner throws out as much 
 carbon dioxide as five men. The unhealthiness of 
 a closed room is also increased by the organic mat- 
 ter of the breath, which is very poisonous.^ The 
 odor of this matter is perceptible in a room long 
 before the accumulation of carbon dioxide reaches 
 a point when it is likely to be injurious. It is, there- 
 fore, to be looked upon as by far the most danger- 
 ous impurity in the atmosphere of an occupied 
 room. 
 
 182. Ventilation. — In order to forestall any evil 
 result from such impurities, the air of a room should 
 be changed frequently enough to prevent the odor 
 of this organic matter from being perceptible. This 
 usually requires some special attention, and is called 
 ventilation. In warm weather, all that is necessary 
 is to open the doors and windows and allow the air 
 to circulate freely through the house. But in cold 
 
 * The composition of this organic matter is not known. It is given 
 off in such small quantity that the chemists have never been able to 
 analyze it. It putrefies rapidly after it has left the body, and then be- 
 comes very offensive. 
 
RESPIRATION. 137 
 
 weather more care is required. A fireplace, with 
 an open fire, is an excellent means of drawing out 
 the foul air — sending it up the chimney, and so out 
 of the house. The fresh air, to supply the place of 
 what has been thus removed, may come in through 
 cracks in the windows^ and doors. But the fresh 
 air admitted in this way in cold weather, being 
 heavier than warm air, falls and sweeps along the 
 floor. This is very dangerous, for few people 
 can endure a cold draught on the feet and ankles, 
 while the rest of the body is warm, without tak- 
 ing cold. Moreover, the smallness of the apertures 
 through which the air comes increases the ra- 
 pidity of the current. It is better, therefore, to let 
 in the fresh air through a special opening, so ar- 
 ranged that the cold air shall not immediately fall 
 to the floor. This can be done cheaply and effect- 
 ively by raising the lower sash of the window about 
 four inches, and putting underneath it a board, fit- 
 ted to close the opening tightly between the sash 
 and the sill. There will then be a long, narrow 
 opening between the upper and lower sash, through 
 which air will enter in a current directed upward 
 toward the ceiling, and, before it descends, its mo- 
 mentum will be so much diminished that it will not 
 create a draught. In very cold places, where double 
 windows are used, the same result may be obtained 
 by raising the lower outer sash a little, and lowering 
 the upper inner one. The best way, however, is to 
 warm the fresh air before it enters the room ; but 
 this is too large a subject for discussion here. 
 
 This foul organic matter from the lungs of ani- 
 mals, when it gets out into the open air, is im- 
 mensely diluted, and, being acted upon b}^ the oxy- 
 
138 ORGANS OF REPAIR. 
 
 gen of the atmosphere, is changed into other and 
 less harmful substances, which, in their turn, are 
 washed down by the rain and become a part of the 
 soil. 
 
 183. Contagions Diseases. — The air is not only 
 polluted by these products of the respiration of 
 healthy animals, but it is made unfit for breathing, 
 in a way involving still more danger to life, by 
 the matters given off from the lungs and bodies of 
 sick persons. There are certain diseases which are 
 called contagions or infectious, because they can be 
 communicated from one person to another. Such 
 diseases are small-pox, measles, scarlet fever, typhus 
 fever, diphtheria, and perhaps consumption.^'' It is 
 known that the matters contained in the air expired 
 from the lungs, or, in some cases, specks of matter 
 cast off from the skins, of persons sick with these 
 diseases, will produce similar diseases in persons 
 who inhale them. Exactly what it is that repro- 
 duces the disease is not known, but there is believed 
 to be a microscopic organism^ peculiar to each dis- 
 ease, which, like a kind of seed, will always produce 
 that disease by its own growth and multiplication 
 whenever it meets with proper conditions. Whether 
 these little organisms ever grow and multiply out- 
 side of the body we do not know, but that they do 
 so in the blood we have abundant evidence. f 
 
 * Whooping-cough, mumps, and chicken-pox, are propagated in a 
 similar manner, but are less dangerous. 
 
 f It is thought by some that malarial fevers (fever-and-ague, etc.) are 
 produced by microscopic organisms of this kind, but this is uncertain. 
 It is well for those who live in districts where such diseases are preva- 
 lent to remember that the poison, whatever it may be, is most active in 
 the spring and fall, at night, and near the surface of the ground. In 
 such a region, and at such a season, therefore, people should not go 
 
RESPIRA TIOX. 
 
 139 
 
 There are other diseases which are beheved to 
 be produced by similar organisms growing and mul- 
 tiplying in the discharges from the stomach and 
 bowels. Such organisms are believed to grow out- 
 side the body as well as inside, and are supposed to 
 be the cause of iVsiatic cholera, typhoid fever, and 
 yellow fever.'^* 
 
 184. Precautions against such Diseases. — It is 
 probable that all of these microscopic organisms 
 (called bacteria, bacilli, micrococci, etc.) which float 
 about in the atmosphere, if they do not find a favor- 
 able place in some animal body, where they can 
 grow and propagate their kind, finally die. If it 
 were not so, the human race would be exterminated 
 by them. But men have two ways of dealing with 
 them so as to prevent their spreading. One is to 
 separate the sick person from well ones, as far as 
 possible, and the other is to kill these little organ- 
 isms as fast as they leave the body and before they 
 can get out of the room. This is accomplished by 
 the use of powerful drugs, called disinfectants. 
 
 Nurses and doctors adopt special means of ward- 
 ing off infection, or are willing to expose themselves 
 
 out after sundown, should keep their bedroom-v/indows closed, and 
 should sleep above the first story. 
 
 * The discharges from the bowels and kidneys of healthy persons, 
 even, are believed to become dangerous when they decompose, and to 
 cause serious diseases. Microscopic organisms multiply in them with 
 great rapidity, and are disseminated in the surrounding atmosphere. 
 For this reason, it is desirable that such matters should be removed 
 from the vicinity of dwellings as quickly as possible. When they are 
 discharged into sewers, their decomposition produces various gases — 
 some of them very offensive — which are popularly known as sewer-gas, 
 but should more properly be called, collectively, sewer-air. The most 
 dangerous thing about sewcr-air, however, is not the offensive gases, 
 but the little organisms that float out with it into the streets or houses. 
 
140 ORGANS OF REPAIR. 
 
 to the risk necessary for the proper care of the sick. 
 If it becomes the duty of any other person to enter 
 a sick-room, he should have in mind the following 
 points : that the nose, on account of its narrow pas- 
 sages and extensive moist surface of mucous mem- 
 brane, acts as a sort of filter, so that many impurities 
 of the air are detained there and never reach the 
 lungs, whereas, through the mouth, there is a straight 
 and almost unimpeded course to those organs ; that 
 the body is less able to resist injurious influences of 
 every kind when it is fatigued or in want of a fresh 
 supply of food ; and that matters escaping from the 
 bodies of the sick and floating in the air are likely 
 to settle on articles' standing in the room. Hence 
 we deduce the following rules : 
 
 Never enter a sick-room when you are hungry or 
 tired. 
 
 Always keep your mouth shut, except zvhen talking. 
 
 Never eat or drink anything that has been standin 
 in the sick-room. 
 
 g 
 
CHAPTER VIIT. 
 
 ASPHYXIA. 
 
 185. Asphyxia. — When the blood is deprived 01 
 its constant fresh supply of oxygen, the carbon 
 dioxide produced in the tissues accumulates very 
 rapidly, and in a short time the blood is brought 
 into a condition in which it can not circulate, pro- 
 ducing asphyxia or suffocation. The blood through- 
 out the whole body then becomes venous. The 
 arteries'" as well as the veins are filled with black, 
 sluggishly-moving blood. This black blood shows 
 through the skin, particularly where it is very thin, 
 as in the lips ; and parts of the body which are usu- 
 ally of a healthy red or pink color become blue and 
 livid. This blueness of the lips and of the flesh un- 
 der the finger-nails is, therefore, a sure indication 
 that the person is suffering from a lack of oxj-gen, 
 and the only thing to do to save life, under such cir- 
 cumstances, is to supply fresh air. In drowning, 
 strangling, poisoning by coal-gas or illuminating* 
 gas, this is always the great thing to be aimed at, 
 and, as long as the heart beats, life exists, and con- 
 sciousness can usually be restored. 
 
 * The arteries are those blood-vessels that carry the bright scarlet 
 blood, which has received a fresh supply of oxygen, and the veins con- 
 vey the dark blood, called venous, which is loaded with carbon di- 
 oxide and other waste matter.^, as hereafter explained. 
 
142 ORGANS OF REPAIR. 
 
 186. Drowning. — The length of time during 
 which a human being may remain under water and 
 still recover, under proper treatment, is not yet act- 
 ually determined. Young persons, it is known, live 
 longer when submerged than older ones. As a rule, 
 however, a person who has been entirely submerged 
 for five minutes is dead beyond the possibility of 
 resuscitation. And yet, even in such cases, attempts 
 should be made, for any case may be an exceptional 
 one."^ 
 
 187. Resuscitation of the Drowned. — What, then, 
 are the indications for the treatment of a person who 
 is almost dead from drowning? 
 
 In the first place, he Tias been for some time de- 
 prived of oxygen. It is this which has made him 
 unconscious. 
 
 In the second place, he has, probably, in his fran- 
 tic efforts to breathe, taken water into his lungs, 
 where it stops up the bronchi and air-vesicles, and 
 must be cleared out before any air can enter. 
 
 In the third place, he is cold, and warmth, of 
 itself, will do much toward bringing about his re- 
 covery. 
 
 In the fourth place, his circulation is at a very 
 low ebb. The blood is so charged with carbon 
 dioxide that it is sluggish, and, possibly, has almost 
 ceased to flow. 
 
 We must first, then, turn the person on his face, 
 and raise the lower part of the body somewhat, so 
 as to let what water there may be in the lungs run 
 
 * Unconsciousness sometimes persists for a long time after a person 
 has been removed into fresh air, when no special attempts at resusci- 
 tation have been made. It is said that persons have been restored by 
 artificial respiration after they have lain unconscious and apparently 
 dead iox Jive hours. 
 
ASPHYXIA. 143 
 
 out by the force of gravity. This action need oc- 
 cupy only an instant, for, if there be any water there, 
 it will immediately run out. 
 
 The person should then be laid flat tipoji the back, 
 without having the head raised, for we want the 
 first fresh blood to run to the brain, and the heart 
 is acting so feebly that it will be unable to send it 
 there if it has to propel it up-hill. The shoulders 
 should be raised a httle by a pillow, a folded coat, 
 or other padding. All the clothing should be loosened 
 about the neck, chest, and waist, so as not to inter- 
 fere at all with the movements of respiration. 
 
 The li'ct, clinging clothing, if convenient, should be 
 removed entirely, as it tends to keep up the chilliness 
 of the body. In any event, some one should attend 
 to the duty of ivarniing the body, by rubbing it with 
 warm flannels, bv bottles of hot water to the feet, 
 etc., etc. 
 
 In addition to these things, and chief of all, arti- 
 ficial respiration should be kept up until the patient 
 breathes naturally, or until absolutely all hope is 
 lost. 
 
 188. Artificial Respiration. — As the person lies 
 upon the back, the arms are to be grasped above 
 the elbows and brought upward above the head, so 
 as to touch, or nearh^ so. The large muscles of the 
 shoulder are attached to the walls of the chest in 
 such a manner that this movement of the arms raises 
 the ribs, and expands the cavity of the chest in very 
 much the same way that ordinary respiration does. 
 The chest being thus expanded, of course air rushes 
 in, and inspiration is effected. The arms should 
 now be returned to the sides of the body and pressed 
 against the ribs, when the chest-walls will recover 
 
144 ORGANS OF REPAIR. 
 
 their former position by virtue of their elasticity, 
 and expel all the air which had been taken in. This, 
 it will be observed, is exactly the process of natural 
 expiration. The rapidity of these movements should 
 approach as nearly as possible to the rapidity of 
 natural respiration — i. e., about sixteen or eighteen 
 movements to the mi7iute, and the drawing up of the 
 arms above the head should occupy the usual time 
 of inspiration. This process should be continued 
 for hours, if necessary, and the first sign of recov- 
 ery Avill usually be a slight change in the color of 
 the lips and finger-nails to red or pink, indicating 
 that the circulation and oxygenation of the blood 
 have begun to be more active. 
 
 189. Additional Precautions. — During the whole 
 process of resuscitation of a drowned person, care 
 should be taken to keep the month and throat clear 
 of mucus and froth by means of a finger covered 
 with a towel. The tongue must also be watched. In 
 persons who are almost dead and have lost their 
 muscular power, this organ often slips backward 
 into the throat, and covers the glottis so that no air 
 can pass in or out. It is necessary, in such cases, 
 for some person to take hold of the tip of the 
 tongue with a towel to prevent its slipping from the 
 grasp, and draw it forward so as to leave the pas- 
 sage to the lungs clear.^" 
 
 As soon as the person begins to* breathe he can 
 swallow, and five grains of carbonate of ammonia 
 should be given him in a quarter of a tumbler of 
 
 * In all cases of asphyxia, pure air is of the utmost importance. 
 The sufferer should therefore be in a well-aired room, and whether in- 
 doors or out should never be surrounded by a crowd of people, whose 
 respiration will pollute the air before it reaches the one who needs it 
 most. 
 
ASPHYXIA. 
 
 145 
 
 water, dry clothing should be placed upon him, 
 and he should be put in a warm bed until his re- 
 covery is complete. 
 
 The above directions apply to all cases ot suffo- 
 cation, where there is no other injury to complicate 
 the results of the mere deprivation of airo 
 
CHAPTER IX. 
 
 THE HEARTo 
 
 190. General Plan of the Circulation. — The cir- 
 culation of the blood is brought about by a compile 
 
 Fig. 41. — The heart and the large blood-vessels connected with it. The 
 greater part of the left ventricle is hidden by the right ventricle. 
 
 cated series of tubes and channels, extending through 
 every portion of the body, and all communicating 
 
THE HEART. 1 47 
 
 with each other and with a powerful muscular cen- 
 tral organ called the Jicart. The tubes are called, 
 according to their structure, size, and function, ar- 
 teries, veins, or capillaries.^ 
 
 191. The Heart. — The heart (Fig. 41) is a strong, 
 hollow, muscular organ, lying behind the breast- 
 bone, with its greater portion to the left of it. It 
 is shaped somewhat like a cone, with both ends 
 rounded, and the larger end directed upward and 
 toward the right. The lower end, or apex, is free 
 to move in any direction, not being attached to any- 
 thing, while the upper and larger end is held in 
 place bv the large blood-vessels which are connected 
 with it and also with the spinal column. The whole 
 orsran is covered with serous membrane called the 
 pericardium, and lies in a cavity which is also lined 
 with serous membrane, so that, like the lungs and 
 abdominal organs, its constant movements can go 
 on with the slightest amount of friction, 
 
 192. The Double Circulation. — In order to un- 
 derstand the action of the heart, it is necessary 
 to know, first, that there is a double circulation go- 
 ing on in the body at the same time. At every 
 contraction of the heart a portion of the blood is 
 thrown into the lungs and another portion into the 
 remainder of the body ; and these two portions 
 never mingle with each other. To be more precise, 
 and follow a particular mass of blood in its course 
 through the body, wx may state it thus : The blood 
 starts, we will say, from a certain part of the heart ; 
 it goes directly to the lungs ; thence it returns to 
 the heart, but to a different part of the organ ; then 
 it g:oes out of the heart in the arteries to what is 
 
 * See Frontispiece. 
 
148 ORGANS OF REPAIR. 
 
 called the general circulation — i. e., to all parts of 
 the body, excepting the lungs ; thence it is collected 
 by the veins, and returns to the heart ; at the next 
 contraction it goes to the lungs again, and begins 
 the same process ; so that in this way all the blood 
 passes through the lungs, and all of the blood visits 
 all parts of the body ; but in doing this it visits and 
 passes through the heart twice. In short, it flows — 
 I. From tJie Jieart to the lungs ; 2. Back to the heart ; 3. 
 Fo the rest of the body; 4. Back to the heart. Thus, 
 there are two systems of circulation : one, called the 
 pulmonary circulation, from the heart to the lungs 
 and back again; the other, tJie general circulation^ 
 from the heart to the body and back again. 
 
 193. The Two Sides of the Heart.^This double 
 and simultaneous circulation can not be brought 
 about by a heart containing but one cavity. And, 
 accordingly, we find that the heart is divided by a 
 muscular partition, running lengthwise of the organ 
 from front to rear, into two parts of nearly equal 
 size, called the right and left sides of the heart. 
 The right side carries on the pulmonary circulation, 
 and the left the general circulation. So that the 
 course af the blood is as follows : From the right side 
 of the heart to the lungs ; thence to the left side of the 
 heart ; thence to all parts of tJie body ; tJience back to 
 the right side of the Jieart. If this order of the circu- 
 lation be carefully observed, it will be seen that the 
 right side of the heart never contains anything but 
 dark or venous blood, and the /^/^j/*^^ always contains 
 bright or arterial blood. 
 
 194. The Auricles and Ventricles. — Each side of 
 the heart is divided into two cavities, making four 
 in the whole organ. These cavities are called the 
 
THE HEART. 
 
 149 
 
 auricles and ventricles. The ventricles constitute the 
 greater part of the heart, and it is in their walls that 
 the greatest muscular power is located. The auri- 
 cles are smaller cavities, situated at the upper ex- 
 tremity of the organ, and their walls are much 
 thinner and weaker than the walls of the ventricles. 
 The blood passes from the veins into the auricles, 
 from the auricles into the ventricles, and from the 
 ventricles it is forced out into the body. The course 
 of the blood, then, is from the bodv in sreneral 
 through the veins to the right auricle ; frojn the right 
 auricle to the righi ventricle ; from the right ventricle to 
 
 the lungs ; from the 
 lungs to the left auri- 
 cle ; from the left au- 
 ricle to the left ventri- 
 cle ; from the left ven- 
 tricle out to the body 
 in general, whence it 
 is collected by the 
 veins and brought 
 back to the right au- 
 the 
 
 to 
 
 begin 
 
 agam 
 
 ricle, 
 
 same course 
 
 (Fig. 42). 
 
 195. The Valves 
 of the Heart. — At 
 the mouths of the 
 veins, where they 
 emptv into the au- 
 ricles, there are no 
 valves, and they are not really needed at this point, 
 for the auricles do not contract with much force, 
 and as there is always a current in the veins running 
 1 1 
 
 Fig. 
 
 42. — Diagram illustrating the course 
 of the blood through the heart. 
 
I50 ORGANS OF REPAIR. 
 
 toward the heart, and as the ventricles lie below the 
 auricles, the blood naturally flows into the ventri- 
 cles, where it meets with no resistance, rather than 
 backward, where it would meet with considerable, 
 having to oppose the force of gravity and also 
 the current in the veins. In this manner the ven= 
 tricles become filled with blood, and, when they 
 begin to contract, the case is very different. Here 
 there is an enormous pressure to overcome. The 
 right ventricle must contract with force sufficient 
 to send its contents into the lungs, pushing be- 
 fore it the column of blood already in the ves- 
 sels. The left ventricle has to contract with a 
 force sufficient to send its contents to the remotest 
 parts of the body, also pushing along the blood 
 which is already in the vessels. On the other hand, 
 the resistance backward toward the veins is not 
 nearly as great. The current of blood in the veins 
 is not strong, and, even supposing that the resistance 
 were equal in both directions, it is plain that the cir- 
 culation would soon come to an end. The ventricle 
 in contracting would force blood backward into the 
 auricles and veins, and forward into the arteries, 
 and then, when the heart relaxed, the blood would 
 flow back again into the ventricles from both direc- 
 tions. This danger is averted by the introduction 
 of four sets of valves, one between each auricle and 
 ventricle, and one at the opening from the ventricle 
 into the artery, through which the blood passes dur- 
 ing contraction. The valves of the heart are double 
 folds of the serous membrane which lines all the 
 cavities of the organ, and are stiffened somewhat 
 by a few fibers which run between the folds. All 
 of these valves have three flaps, excepting the one 
 
THE HEART. 151 
 
 which separates the left auricle from the left ventri- 
 cle, and this has only two. 
 
 The valves are all so constituted as to allow the 
 blood to pass only in one direction. The valves be- 
 tween the auricles and ventricles will allow blood 
 to pass from the auricles into the ventricles, but not 
 from the ventricles back into the auricles ; and the 
 valves at the mouths of the arteries will allow blood 
 to pass from the ventricles into the arteries, but not 
 from the arteries back into the ventricles. 
 
 196. The Blood-Vessels connected with the Heart. 
 - — The large veins, by which all the blood from the 
 general circulation is poured into the right auricle, 
 are called the vcncc caves (i. e,, the hollow veins) ; the 
 large artery, by which the blood passes from the 
 right ventricle to the lungs, is X\\q pulmonary artery ; 
 the large veins, by which the blood returns from 
 the lungs and enters the left auricle, are the pulmo- 
 nary veins ; and the large artery, by which the blood 
 goes out from the left ventricle to all parts of the 
 body, is called the aorta. 
 
 197. The Circulation of the Blood. — The blood, 
 then, coming from all parts of the body in the veins, 
 enters through the venas cavas into the right auri- 
 cle ; when the auricle is filled, it contracts and sends 
 the blood downward into the right ventricle ; when 
 the ventricle is filled, its walls contract, and the 
 blood passes into the pulmonary artery, its return 
 into the auricle being prevented by the closure of 
 the valves between the auricle and ventricle ; the 
 blood then goes through the lungs, and becomes 
 changed into arterial blood ; it returns to the heart, 
 to the left auricle, and passes from there into the 
 left ventricle ; the contraction of the ventricle then 
 
152 ORGANS OF REPAIR. 
 
 forces it into the aorta, its return into the auricle 
 being prevented by the valves ; from the aorta it 
 goes to all parts of the body, to be returned by the 
 veins to the right side of the heart. The valves at 
 the mouth of the pulmonary artery and the aorta 
 prevent the blood which has entered them during 
 the heart's contraction from flowing back into the 
 cavity of the ventricle when it becomes relaxed. 
 
 198. Peculiar Valves in the Heart. — There is one 
 peculiarity connected with the working of certain 
 valves in the heart which is one of the most beauti- 
 ful examples of adaptation in the whole body. It 
 has been shown that there are no valves at the 
 points where the veins enter the auricles, and still, 
 when the auricles contract, the blood is not forced 
 backward in the veins to any great extent, but passes 
 downward into the ventricles. Some of the reasons 
 for this have already been mentioned, but there is 
 the additional fact that the opening between the 
 auricle and ventricle on each side is very large, al- 
 most as wide as the auricle itself. There is, there- 
 fore, very little resistance, hardly any in fact, to the 
 stream of blood passing from either auricle to the 
 ventricle. But this large size of the opening might 
 give rise to imperfect closure of the valves. The 
 valves are made of thin sheets of membrane, stiffened 
 a little by fibrous threads, but still very flexible. In 
 the pulmonary artery and the aorta, the openings 
 from the ventricles are so small that the valves are 
 stiff enough to resist the backward pressure of the 
 blood and keep the openings closed. The openings 
 from the auricles to the ventricles, however, are so 
 large that, if there were no special provision to pre- 
 vent it, the valves would not only be pressed back- 
 
THE HEART, 
 
 153 
 
 ward toward the auricle when the ventricle con^ 
 tracted, so as to meet at their edges and close the 
 opening, but, on account of their flexibility, their 
 borders would be bent still farther back, so as to 
 open into the auricle, and allow a reflux of blood 
 into that cavity. 
 
 This difihculty is obviated in the following man- 
 ner : There are numerous fine but strong fibrous 
 threads or cords attached to the edges of the valves, 
 and from that point running downward to the walls 
 of the ventricle. These cords are just long enough 
 to allow the valves to close perfectly, but not pass 
 any farther back toward the auricle. But here an- 
 other difficulty arises. If the cords are long enough 
 to allow the valves to close at the beginning of the 
 contraction of the ventricle when the cavity is at 
 its full size, then they will be too long when the 
 contraction is toward its end and the cavity is di- 
 minished in size, and allow the valves to be pressed 
 
 Ftg. 43. — Illustrating the action of the valves in the right side of the heart:. 
 
154 
 
 ORGANS OF REPAIR. 
 
 too far back. In other words, to fulfill their object, 
 these cords must be able to become longer or short- 
 
 FiG. 44. — Illustrating the action of the valves in the right side of the heart. 
 
 er according to circumstances. This is effected by 
 small muscular projections or pillars, which extend 
 from the walls of each ventricle into its interior, and 
 to which the cords are attached. When the heart 
 contracts, these little pillars contract at the same 
 time, and make the cords attached to the valves 
 shorter and shorter as the contraction proceeds, just 
 in proportion as the cavity of the ventricle grows 
 smaller and smaller. In this way the reflux of blood 
 through these large valves is prevented (Figs. 43, 
 
 44). 
 
 199. The Contraction of the Heart. — The con- 
 traction of the heart does not run successively from 
 one auricle to the corresponding ventricle, and then 
 from the other auricle to the other ventricle, but the 
 contraction of both sides of the heart is simultane- 
 
THE HEART. \tt 
 
 3D 
 
 ous« It beirins at the auricles and extends down- 
 ward until the ventricles are both firm and hard and 
 reduced to their smallest possible size. The organ 
 then becomes relaxed, and is for an exceedingly- 
 short time quiet. During this stage of relaxation 
 the auricles are being filled with blood from the 
 veins, and there is also a current running into the 
 ventricles from the auricles. During the stage of 
 contraction the blood is being forced into the circu- 
 lation through the aorta and the pulmonary artery. 
 
 200. The Sounds of the Heart. — These alternate 
 contractions and relaxations of the heart are accom- 
 panied by sounds, which are very audible to any one 
 who applies his ear to the region of the heart in a 
 living person. These sounds are two in number, the 
 first being a prolonged, rumbling sound, and the 
 second short and sharp. The first sound is made 
 during the time when the heart is contracting, and 
 the second ]W'^t at the end of the contraction, or be- 
 ginning of relaxation. The first sound is supposed 
 to be produced partly by the closing of the large 
 valves between the auricles and ventricles, which 
 occurs just at the moment when this sound begins, 
 and partly by the contraction of the muscular fibers 
 of the heart. The second sound is positively known 
 to be produced by the closing of the pulmonary and 
 aortic valves. It is by the variation in distinctness 
 and quality of these sounds, and the addition of 
 other sounds to them, that physicians are enabled to 
 determine with wonderful accuracv the condition of 
 the valves of the heart. 
 
 201. Nervous Supply of the Heart. — The heart 
 is plentifully supplied with nerves, which regulate 
 its movements. One set, belonging to the cerebro- 
 
156 ORGANS OF REPAIR. 
 
 spinal system (which will be treated in the chapter 
 on the nervous system), have the power of check- 
 ing or arresting the heart's action, and are there- 
 fore called the inhibitory nerves of the heart. An- 
 other set, having an opposite function — i. e., that 
 of increasing the heart's action — are called the ac- 
 celerator nerves. If the inhibitory nerve is de- 
 stroyed, or temporarily paralyzed, the pulsations 
 of the heart are suddenly increased. If the accel- 
 erator nerve is paralyzed, the heart ceases to beat. 
 202. Rapidity of Pulsation in Health. — The con- 
 tractions of the heart take place with regularity, and 
 average in the adult about seventy per minute. The 
 rate is higher in children and women than in men, 
 and this fact is probably connected with their great- 
 er impressionability. The heart-pulsations appear 
 to be slower in proportion as the individual is cool 
 and deliberate in his judgments. The pulse of Na- 
 poleon Bonaparte is said to have averaged only 
 forty-four to the minute, and is one of the slowest 
 on record. Sudden emotions may increase its ra- 
 pidity and force, so that a process of which we are 
 usually unconscious becomes very perceptible and 
 unpleasant, or, on the other hand, they may cause 
 it to stop for a moment altogether, to skip a beat, 
 as it were, producing the sensation of " fluttering " 
 at the heart. Although the action of the heart is 
 thus influenced by our feelings, it is beyond our 
 control. Its pulsations are ceaseless and regular, 
 until interrupted by disease or death. But, not- 
 withstanding this general fact, there are some in- 
 stances on record of persons who have been able to 
 affect the action of the heart by an effort of the will. 
 The most remarkable one of these, perhaps, was a 
 
THE HEART. 1 57 
 
 Colonel Townsend, of Dublin. This person, on sev- 
 eral occasions, iii the presence of medical men, lay 
 down and caused the contractions of his heart to 
 become so faint as to be imperceptible. During 
 the experiment the circulation was so far interfered 
 with that he became pallid and unconscious. After 
 a half-hour or so, he would gradually return to his 
 natural condition. As might have been expected, 
 he performed the experiment once too often. He 
 stopped the action of the heart for the last time in 
 the same way as he had done before, and it never 
 resum.ed its work. 
 
 203. Effect of Alcohol upon the Heart. — A small 
 quantity of alcohol increases the frequency of the 
 heart's beats bv paralyzing for a time its inhibitory 
 nerve. The effect may be compared to removing 
 the balance-wheel from a watch or the drag from a 
 wagon-wheel as it is going down-hill. The proper 
 restraint being taken off, the heart's movements 
 become at once more hurried and frequent. It is a 
 wise provision of Nature that the accelerator nerves 
 belong to a part of the nervous system that is much 
 more slowly influenced by any disturbing agent than 
 the inhibitory. If this were not the case, and the 
 accelerator nerve were as quickly affected as the in- 
 hibitory, life would be in frequent jeopardy from the 
 effects of injurious substances which men either reck- 
 lessly or ignorantly take into their systems. When- 
 ever the heart is compelled to more rapid contraction 
 than is natural, it has less time to rest. Although this 
 organ seems to be constanth' at work, it really rests 
 more than half the time, the time occupied by a con- 
 traction being to the time between the contractions 
 about as two to three, so that, although the periods 
 
158 0RG4^'S OF REPAIR. 
 
 of relaxation are very shoi"t, they are so numerous 
 (seventy or more a minute) that the aggregate 
 amount of rest in a day is very great. Now, if the 
 rapidity of the contractions is increased material- 
 ly 'and continuously, although the aggregate amount 
 of time for rest may be the same as before, yet the 
 waste caused by the contractions is greater, while the 
 time for rest after each one is shorter. This lack of 
 rest produces exhaustion of the heart-muscle, ending 
 in partial change of the muscular tissue into fat. The 
 heart then becomes flabby and weak and its walls 
 become thinner, a condition known to physicians as 
 a *' fatty heart," often resulting in sudden death. 
 
 204. Effect of Tobacco on the Heart. — The use 
 of tobacco often produces functional derangement 
 of the heart's action. The pulse becomes weak and 
 intermittent, and palpitation of the heart is common. 
 These effects are so well known that symptoms of 
 this kind in a boy or man, without any discoverable 
 organic disease to account for them, are at once put 
 down by physicians as due to a '' tobacco heart." 
 This weakness of the heart is probably due to the 
 influence of tobacco upon its nervous supply, and 
 its immediate efTect is seen in a languid circulation, 
 imperfect blood-changes, pallor of the face, and 
 occasional fainting-spells, especially in the young. 
 These are the symptoms oftenest produced by the 
 smoking of cigarettes, and they have been some- 
 times attributed to the paper in which the tobacco 
 is wrapped, or to the drugs with which it was adul- 
 terated. But this is mere beating about the bush. 
 The most hurtful ingredient of the cigarette is the 
 tobacco, just as truly as the most hurtful ingredient 
 of fermented drinks is the alcohol. 
 
CHAPTER X. 
 
 THE BLOOD-VESSELS. 
 
 205. The Blood-Vessels. — The heart, although 
 a very powerful organ, would not be able to force 
 the blood through the whole body, and back to itself 
 again, without assistance, and this assistance is fur- 
 nished by the structure of the blood-vessels them- 
 selves. The blood leaves the heart by the arteries 
 and comes back to it through the veins, and these 
 two systems of vessels differ very much in their 
 structure. 
 
 206. Structure of the Arteries. — The arteries are 
 tubes, with strong walls, described by anatomists 
 as having three layers. The innermost is a delicate, 
 smooth membrane ; the nmidle one is composed of 
 elastic fibers and also fibers of the non-striated or 
 involuntary muscular tissue ; the outer one is made 
 up of strong connective tissue. Thus the walls of 
 the arteries are very. elastic, and, if the tube is dis- 
 tended, it returns to its former size as soon as the 
 internal pressure is removed. 
 
 207. The Pulse. — When the heart contracts, its 
 contents are driven with great force into the ar- 
 teries, and, as the blood already contained there re- 
 sists somewhat the advance of the fresh supply, the 
 walls of the arteries arc stretched to accommo- 
 
l6o ORGANS OF REPAIR. 
 
 date the mass of blood which is thrown into them^ 
 When the heart relaxes, and the pressure from that 
 direction is removed, the elastic walls of the arteries 
 react upon their contents, and, if it were not for the 
 valves, would drive the blood, or a portion of it, 
 back into the heart. At the slightest backward 
 pressure, however, the valves close, and the elas- 
 ticity of the arteries thus gives the blood another 
 impulse forward toward the surface of the body. 
 The impulse given by the heart's contraction, to- 
 gether with that caused by the recovery of their 
 natural position by the walls of the arteries, gives 
 rise to the pulse, which can be felt at any point in 
 the body where an artery runs near enough to the 
 surface. The common place of feeling for it is in 
 the wrist, merely because that is the most conven- 
 ient and accessible ; but it may also be felt in the 
 ankle, in the neck, in the temple, or in the upper 
 arm. 
 
 208. The Capillary Blood-Vessels ; their Struct- 
 ure. — The large vessels, by which the blood leaves 
 the heart, viz., the pulmonar}^ artery and the aorta, 
 divide and subdivide continually, the branches 
 growing smaller and "Smaller as they approach 
 their termination, their walls at the same time un- 
 dergoing a change in structure. The elastic tissue, 
 which is so abundant in the larger arteries, grad-= 
 ually disappears as the vessels diminish in size, and 
 the muscular tissue becomes more prominent, until 
 even this finally vanishes, and the smallest blood-, 
 vessels, called the capillaries, are composed of a 
 thin membrane, not divisible into layers. Thus the 
 largest arteries are very strong and very elastic, 
 while the smaller ones lose in elasticity, but, from 
 
THE BLOOD-VESSELS. i6l 
 
 the amount of muscular tissue they contain, are 
 very contractile. 
 
 209. Size of the Capillaries. — The capillaries, in 
 which the arteries finally end, are only about the 
 gQ^QO of an inch in diameter — just large enough to 
 allow the blood-corpuscles to pass through them, 
 so to speak, in single file. Their number is beyond 
 computation. They are so thickly strewed in the 
 body that the point of a fme cambric needle can 
 not anywhere be inserted between them. As every 
 one knows, it is impossible to find an instrument 
 with a point so fine as not to wound a blood-vessel 
 if introduced through the skin. These vessels are 
 entirely indistinguishable to the naked eye, and, be- 
 fore the discovery of the microscope, it was a great 
 problem for anatomists to explain how the blood 
 got from the arteries into the veins, as they could 
 find no direct communication. 
 
 210. The Veins. — After passing through the cap- 
 illaries, the blood oncers the veins. These vessels 
 contain in their walls much less muscular and elas- 
 tic tissue than the arteries, and more connective 
 tissue. The consequence of this is, that the walls 
 of the veins are flaccid and yielding, and, if they are 
 cut across, the sides fall together and tend to close 
 the opening. If an artery, on the other hand, be 
 cut, the tube remains open and in a sense rigid, al- 
 though, as will soon be shown, its caliber is some- 
 what diminished. The veins, very minute at first, 
 gradually unite and become larger and larger, until 
 finally all the veins of the general circulation form 
 two large vessels, called the veiue cavtu, which dis- 
 charge their contents into the right side of the 
 heart — one vena cava receiving all the blood from 
 
1 62 ORGANS OF REPAIR. 
 
 the head and upper extremities, and the other that 
 from the rest of the body. 
 
 211. Circulation of Blood in the Veins ; Influ- 
 ence of Respiration. — The circulation of the blood in 
 the veins is brought about in three ways : In \}i\^ first 
 place, the act of respiration has its influence. When 
 the chest is expanded by muscular action, every 
 fluid which is outside of it tends to rush in and fill 
 the enlarged cavity. The chief space is filled by 
 the air, as that is more perfectly fluid and meets 
 with the least resistance from friction. But the 
 blood is also drawn in through the veins, and the 
 real extent and power of this suction can be very 
 easily seen whenever the entrance of air is im- 
 peded. In such cases the veins in the neck can be 
 plainly seen to become swollen and full during ex- 
 piration, and emptied again during inspiration. 
 
 212. Influence of Muscular Contraction. — In the 
 second place, the contraction of the voluntary mus- 
 cles aids in the return of the blood to the heart. 
 While the arteries, as a rule, run deep in the body, 
 out of the reach of^injury, the veins are largely near 
 the surface, and the whole exterior of the body is 
 more or less streaked by the blue lines which indi- 
 cate their course. Now, during the contraction of 
 a muscle, it not only shortens but becomes broader 
 and thicker, and, of course, compresses to a greater 
 or less degree everything near it. Thus the veins 
 are continually being pressed upon here and there, 
 in various parts of the body, during the whole of 
 our waking hours, and even to some extent during 
 sleep. 
 
 213. The Valves of the Veins. — But merely 
 pressing the blood out of a certain portion of a 
 
THE BLOOD-VESSELS. 
 
 163 
 
 vein misfht send it in either direction ; it would be 
 almost as likely to send it away from the heart as 
 toward it. This reflux of blood in the veins is pre- 
 vented by valves (Fig. 45), which allow the blood to 
 pass through them readily toward the heart, but 
 not away from it." These valves are particularly 
 
 Fig. 45. — Diagrams illustrating the action of the valves in the veins. 
 
 numerous in the lower extremities, for here the 
 force of gravity acts in opposition to the current of 
 blood, and would seriously interfere with the circu- 
 lation if there were no special provision with refer- 
 ence to it. 
 
 Thus, when blood has been forced out of a por- 
 tion of a vein by pressure, it can not go backward 
 on account of the valves, but must go forward in 
 every case. This fact and the action of the valves 
 may be beautifully seen in the arm of any person, 
 where the veins are not obscured by too much fat 
 beneath the skin. If a place be chosen where a vein 
 
 * It is said that tlie discoveiy of the proper working of these valves 
 first suggested to William Harvey the time theory of the circulation of 
 the blood. 
 
1 64 ORGANS OF REPAIR. 
 
 is visible, with no branches for an inch or so, and 
 one finger be placed upon it so as to stop the flow 
 of blood, the portion of the vein on the farther side 
 from the heart will be seen to fill with blood, and 
 at some point will probably look swollen. This 
 slight swelling marks the situation of a valve. If 
 a finger be passed along a vein toward the heart, 
 pressing upon it all the time, the vein will be seen 
 to fill behind the finger ; while if the finger be 
 passed in the opposite direction, away from the 
 heart, the vein will be empty and collapsed behind 
 the finger, and perhaps hardly noticeable. This 
 clearly indicates the direction of the current of 
 blood. 
 
 214. Influence of the Pressure in the Capillaries. 
 —But the thh'd cause of the venous circulation, and 
 the most important of all, is the blood which is con- 
 stantly accumulating in the capillaries and exercis- 
 ing pressure on the column of blood already in the 
 veins. This pressure is unceasing and powerful. 
 
 These three causes, acting together, keep up a 
 free and steady flow of blood in the veins toward 
 the heart. 
 
 215. Communicating Blood- Vessels. — In both ar- 
 teries and veins, there are numerous communicat- 
 ing branches, so that, when a blood-vessel is ob- 
 structed, the blood passes out into other vessels and 
 around the point of stoppage, and, excepting in ex- 
 traordinary cases, the nutrition of the part is not in= 
 terfered with. 
 
 216. Recapitulation : Rapidity of the Blood^Cur- 
 rent in the Vessels. — The arteries, then, carry the 
 bright scarlet, highly oxygenated blood from the 
 heart out to all parts of the body for its nutrition. 
 
THE BLOOD-VESSELS. 165 
 
 It is sent to the remotest capillaries, partly by the 
 contraction of the heart, and partly by the elasticity 
 of the arteries ; from the arteries it enters the capil- 
 laries, where the essential but very obscure processes 
 of nutrition are carried on. It has been found that 
 the current of blood rushes through the arteries 
 with an average velocity of twelve inches per sec- 
 ond, but, in consequence of the smallness of the cap- 
 illaries and their distance from the heart, as well 
 as the magnitude of their combined areas as com- 
 pared with that of the aorta, the blood moves 
 through them very slowly, not faster, it is thought, 
 than one thirtieth of an inch per second. When the 
 capillary circulation is looked at through a micro- 
 scope, as it may be in the web of a frog's foot," it 
 is seen that the red corpuscles pass along through 
 the minute vessels, sometimes two together, but 
 oftener in single file, and without much trouble ; 
 but the white corpuscles are more affected by fric- 
 tion, and drag along, sticking fast here and there 
 until they are started again bv the current. During 
 the passage of the blood through the capillaries, 
 certain of its insfredients transude throusfh the 
 walls of the blood-vessels, and lie in immediate 
 contact with the tissues outside ; these are the 
 nutritive materials by which the various tissues of 
 the body are kept in repair ; the cells select their 
 nourishment, and what is left, together with waste 
 and used-up matters from the cells, is taken up by 
 the Ivmphatic vessels and returned to the large 
 
 * The foot of a live frog may easily be fastened by strings so that it 
 can be placed under the microscope. The thin membrane is transpar- 
 ent, and the circulation of the blood, as seen in this way, is perhaps the 
 most surprising and instructive sight that can be witnessed. 
 12 
 
1 66 ORGANS OF REPAIR. 
 
 veins near the heart. These matters constitute 
 what is called the lymph. Changes in the gaseous 
 constituents of the blood also take place in this part 
 of the circulation, and so we find that, when the 
 blood emerges from the capillaries into the veins, 
 it has become of a dark-purple color, and unfit for 
 further use in the body until refreshed. So the 
 process which takes place in the capillaries is in 
 some degree the reverse of that which takes place 
 in the lungs. The blood enters the lungs of a black 
 or deep-purple color and comes out bright red. It 
 enters the capillaries bright red and comes out dark 
 purple. It then passes back to the heart through 
 the veins, the steady flow being maintained partly 
 by the suction caused in the act of respiration, part- 
 ly by muscular contraction and consequent pressure 
 on the veins, and mainly by the pressure from the 
 capillaries, which constantly forces the blood on- 
 ward. 
 
 217. Peculiarity of Pulmonary Artery and Veins. 
 — There is one exception to the rule that the arteries 
 carry scarlet blood, and one to the rule that the 
 veins carry purple blood. The pulmonary artery 
 carries venous blood from the right side of the heart 
 to the lungs, and the pulmonary veins bring back 
 scarlet or arterial blood from the lungs to the left 
 side of the heart. 
 
 218. Rapidity of Venous Circulation. — The ra 
 pidity of the current in the veins is estimated at 
 about two thirds of that in the arteries, or about 
 eight inches per second. As all the blood which 
 goes out through the arteries must return through 
 the veins, it might be inferred that the velocity of the 
 flow in both systems of vessels would be the same. 
 
THE BLOOD-VESSELS. 167 
 
 If the capacity of the vessels were the same, it would 
 necessarily be so, but there are generally, with rare 
 and unimportant exceptions, two veins returning 
 the blood sent out by one artery, so that the capac- 
 ity of the venous system is as a whole about twice 
 that of the arterial, and the velocity would be half 
 as great ; but, if we take into account the difference 
 in the distention and fullness of the two systems, 
 the estimate given above is probablv nearly correct. 
 
 219. Rapidity of the General Circulation. — An 
 interesting question arises with regard to the ra- 
 pidity of the general circulation. Experiments have 
 been made which show that this is somewhat great- 
 er than would have been expected. A substance 
 which remains unaltered in the blood, and which 
 can easil}^ be detected by chemical means, was in- 
 troduced into a laro^e vein on the ris^ht side of the 
 neck. It was plainly detected in the blood drawn 
 from the vein of the left side, in from twenty to 
 twenty-five seconds. In this short time, the blood 
 in which the substance was introduced must have 
 gone down to the right side of the heart, fi'om there 
 to the lungs, thence to the left side of the heart, and 
 thence through arteries to the head, before it en- 
 tered the vein in which it was detected on its way 
 back to the heart. 
 
 The time required for all of the blood in the 
 body to pass through the heart can not be accurate- 
 ly determined, but only estimated. It probably 
 varies verv much with the vis^or of the heart's ac- 
 tion, the amount of exercise taken, the frequency of 
 the respiration, etc. In the dead body, however, 
 each ventricle is found to contain about two ounces 
 of fluid. Now. one ventricle is to be estimated in 
 
l68 ORGANS OF REPAIR, 
 
 the calculation, because, in order to complete the 
 entire round of the body, all the blood must pass 
 through the left ventricle. If two ounces enter and 
 leave the ventricle at every contraction of the heart, 
 and there are seventy pulsations in a minute, one 
 hundred and forty ounces, or eight and three quar- 
 ter pounds, will pass through the organ in this short 
 time. Estimating, then, thirteen pounds of blood as 
 the average amount in an adult, two minutes at the 
 most would suffice for the completion of the circu- 
 lation, and this is probably pretty near the truth. 
 
 220. The Supply of Blood in any Part varies.— 
 The amount of blood in any portion of the body at 
 any particular time depends upon certain relations 
 which exist between the blood-vessels and the nerv- 
 ous system. The walls of the arteries are plen- 
 tifully supplied with involuntary muscular fibers. 
 The contraction of these fibers diminishes the cali- 
 ber of the artery. They are most abundant in the 
 small arteries, and their contraction or relaxation is 
 controlled by certain nerves called vaso-motor nerves^ 
 because they control or cause motion in the ves- 
 sels to which they are distributed. If the nervous 
 stimulus be such as to cause a contraction of the 
 arteries supplying any particular part of the body, 
 the supply of blood to that part will be diminished, 
 and will be diminished in exact proportion to the 
 amount of contraction in the blood-vessels. If, on 
 the other hand, the nervous control be altogether 
 withdrawn, and the arterial walls completely re- 
 laxed, the amount of blood in the part affected will 
 be increased to a corresponding extent. 
 
 221. Effect of Alcohol on the Blood-Vessels. — 
 Alcohol, even in a moderate dose, produces dilatation 
 
THE BLOOD-VESSELS. 169 
 
 of the superficial blood-vessels, by narcotizing or 
 paralyzing the vaso-motor nerves. This accounts 
 for the flushing of the face which follows so soon 
 after the drinking of any alcoholic liquor. This dila- 
 tation of the small vessels, which produces such visi- 
 ble effects on the external surface of the body, also 
 takes place in parts hidden from sight. The brain, 
 lungs, heart, liver, kidneys, and stomach are all 
 congested, and the secretions increased in amount. 
 222. Diseases of Blood-Vessels caused by Al- 
 cohol. — If alcoholic drinks are used habitually, this 
 dilatation becomes permanent, partly from their 
 effect on the vaso-motor nerves, and partly from a 
 loss of elasticity in the walls of the vessels them- 
 selves, owing to a deposit of a fatty nature, which 
 occurs in spots between the middle and internal 
 coats, making the walls of the vessels weaker at 
 such points. The pressure of the blood produces a 
 gradual stretching and thinning of the wall of the 
 vessel at these weak spots, resulting in the forma- 
 tion of a hollow tumor, like a bladder, on the side 
 of the vessel, in which the blood eddies round, like 
 the water in a whirlpool. This disease is called 
 aneurism, and is a very distressing and dangerous 
 one. The tumor presses upon neighboring nerves, 
 causing obstinate neuralgias and sometimes paraly- 
 sis, and when the outside coat has become so thin 
 that it can resist the pressure of the blood no longer, 
 it bursts, and a fatal haemorrhage is the result. The 
 loss of elasticity in the arteries, produced in the 
 way just described, also disastrously affects the cir- 
 culation, for when they are filled with blood they 
 do not react sufficiently upon it. When the heart 
 contracts again, therefore, and throws a fresh sup- 
 
I/O 
 
 ORGANS OF REPAIR. 
 
 ply of blood into them, it has to be forced along in 
 large part by the heart alone, whereas in healthy 
 persons the arteries do a good share of the work. 
 Thus the heart becomes enlarged and contracts 
 more powerfully at the same time that the walls of 
 the vessels are weakened by disease, and they often 
 burst under the increased pressure, causing what 
 is known as apoplexy. 
 
 223. Features of the Habitual Alcohol-Drink- 
 er. — The permanent dilatation of the surface blood- 
 vessels produces a permanent flushing of the face in 
 drinking men, and often some of the veins are so 
 enlarged that they show as red streaks upon the 
 cheeks and nose. The white of the eye, for the 
 same reason, becomes red. The circulation of the 
 blood in these dilated vessels being sluggish, the 
 nutrition of the skin is interfered with, and it may 
 be covered with red blotches, or disfigured by pim- 
 ples, especially on the nose. The circulation in the 
 latter organ being naturally more feeble than else- 
 where on the face, it shows these effects earlier and 
 more plainly, and sometimes becomes almost purple 
 in color and knobbed and swollen at the end. 
 
 224. The Aorta. — The blood destined for the 
 general circulation all leaves the heart through the 
 aorta. This is a large vessel, about five eighths of 
 an inch in diameter, with thick, strong walls, as it 
 has to bear an enormous pressure. It begins at the 
 upper end of the left ventricle and on its right side, 
 and, after leaving the heart, springs upward toward 
 the right, near the breastbone, to the second rib ; 
 then arches backward, and passes between the lungs 
 to the back ; here it curves again, and runs down 
 along the spine, through the diaphragm, to the 
 
THE BLOOD-VESSELS. 
 
 171 
 
 lower portion of the abdomen — all the way lying 
 in front of the vertebrse. When it reaches the pel- 
 vis it divides into two branches, one of which goes 
 to each lower extremity. 
 
 225. The Femoral Arteries. — These branches 
 run the same course in either limb. They emerge 
 from the abdom.en on the front of the limb, in the 
 groin, not far beneath the skin, and pass in as 
 straight a line as possible on the inside of the thigh 
 to a point behind the knee-joint, at about the middle 
 
 of the hollow space which is 
 found there between the ten- 
 dons on each side. In its 
 course along the thigh the 
 vessel is called the femoral 
 artery (Fig. 46). At the knee 
 it again divides into two 
 branches, one of which runs 
 down in front of the leg, and 
 the other behind to the foot, 
 where they further subdivide, 
 to supply each of the toes 
 with a small arterv on each 
 side. All through this course, 
 however, arteries of different 
 sizes are given off as branches 
 to supply the different organs 
 in the chest and abdomen, as 
 well as the muscles and skin, 
 the course of the main arter- 
 ies only being here indicated. 
 226. The Brachial Arter- 
 ies. — From the arch of the 
 aorta spring upward the vessels which suppl}- the 
 
 / 
 
 Fig. 46.— The right thigh. 
 The dotted line represents 
 the course of the main ar- 
 tery (the femoral). 
 
1/2 
 
 ORGANS OF REPAIR. 
 
 neck and head and upper extremities. Two large 
 vessels go to the arms, one to each. They pass 
 upward and outward between the collar-bone and 
 the first rib, and dip down 
 from the neck, passing to 
 the arm through the arm- 
 pit. As soon as the artery 
 enters the arm it is called 
 the brachial, and it con- 
 tinues its course down the 
 inside of the limb to the 
 elbow, where it comes in 
 front (Fig"! 47). Here it 
 divides in two, the radial 
 and ulnar, which pass 
 down, one on each side of 
 the arm, to the hand, where 
 their subdivision furnishes 
 a small artery for each side 
 of each finger and the 
 thumb. These vessels also, 
 throughout their course, 
 give off branches to the 
 muscles and other parts. 
 The radial artery is the one ordinarily felt in order 
 to judge of the pulse, and is easily found on the 
 radial or thumb side of the arm, about an inch above 
 the fold where the hand bends upon the arm. 
 
 227. The Carotid and Vertebral Arteries. — Four 
 arteries supply the head and face. These are the 
 two carotid arteries in front and the two vertebral 
 behind. The two carotids pass up on each side of 
 the neck, and, when they approach the skull, divide 
 into two main branches, one of which supphes the 
 
 Fig. 47. — The left upper arm. The 
 dotted Hne represents the course 
 of the main artery (the brachial). 
 
THE BLOOD-VESSELS. 173 
 
 face, while the olher enters the skull and supplies 
 the brain. The vcrtebrals supply the brain, and pass 
 up to it almost the entire distance inside the bones 
 of the spinal column. It is important to know the 
 course of the carotid. There is a powerful muscle 
 in the neck, which passes upward from the upper 
 end of the breastbone and parts in its vicinity to a 
 point just behind the ear, where it is attached to the 
 skull. Its contraction turns the head, or, with other 
 muscles, bends it over to one side or the other. Its 
 outline is distinctly perceptible under the skin, par- 
 ticularly when it is somewhat contracted, and the 
 head thereby a little twisted. The carotid artery 
 runs very nearly along the anterior border of this 
 muscle, and its beating may be readily felt in this 
 situation. 
 
 228. The Large Veins. — Each artery is usually 
 accompanied by one or two veins — the largest by 
 one, and the smaller ones by two. The veins are 
 called, as a rule, by the same name as the correspond- 
 ing artery, the most notable exception to this being 
 ihQ Jugular veins, which are the companions of the 
 carotid arteries, and run close by their side. All the 
 blood from the lower part of the body is finally col- 
 lected in a large vein, called the vena cava inferior, 
 which runs up the spine beside the aorta, while that 
 from the head, neck, and upper extremities is col- 
 lected in the vcjia cava superior, and both these large 
 veins discharge their contents into the right auricle 
 of the heart. The veins which take the blood from 
 the digestive organs unite to form \\\q portal vein, 
 which enters the liver, and the large vein which 
 emerges from the liver joins the vena cava inferior, so 
 that all the blood from the digestive organs must go 
 
174 
 
 ORGANS OF REPAIR. 
 
 through the liver before it enters the general circu- 
 lation. 
 
 The pulmonary artery, soon after it leaves the 
 right ventricle, divides into two branches, one of 
 which passes under the arch of the aorta, before 
 described, to the right lung, and the other goes to 
 the left lung. The corresponding pulmonary veins 
 are two from each lung, and they empty their con« 
 tents into the left auricle. 
 
CHAPTER XI. 
 
 DISORDERS OF CIRCULATION. — HAEMORRHAGE. 
 
 229. Obstruction of the Circulation. — If a cord 
 be tightly bound about a finger, that part of the 
 member which is farthest from the heart will soon 
 become livid and begin to swell. This effect is due 
 to the difference in structure and position of the ar- 
 teries and veins. The arteries are tubes with stiff, 
 elastic walls, and do not usually lie very near the 
 surface, whereas the veins have thin, inelastic walls, 
 and many of them are very superficial. The conse- 
 quence is that it is a somewhat difficult matter to 
 compress an artery so as to entirely prevent the 
 flow of blood through it, while the veins are very 
 easily compressed. In binding a cord around the 
 finger, then, unless great force be applied, the veins 
 are compressed and the current of blood in them 
 checked, while that in the arteries is not at all or 
 only slightly interfered with, so that blood is being 
 continually carried into the finger, and can not flow 
 out. The accumulation of blood in the part ac- 
 counts for the swelling, and the dark color is that of 
 venous blood. If, now, the cord be removed, the 
 swelling does not immediately disappear, because 
 wherever there is a damming of the current of blood 
 so that its flow in the veins is interfered with, after 
 
176 ORGANS OF REPAIR. 
 
 the vessels become distended to a certain point, the 
 pressure on their walls is relieved by the loss of a 
 portion of their contents. The serum of the blood 
 begins to pass through the walls of the veins into 
 the tissues outside of them, producing the condition 
 called dropsy.'^ When the circulation of the part is 
 restored, all this serum which has left the vessels 
 has to be reabsorbed, partly by the blood-vessels 
 and partly by the lymphatics, and this occupies an 
 appreciable time. 
 
 Now, let us suppose that this obstruction, instead 
 of being applied to the veins on the surface of the 
 body, is situated in some of the interior organs. It 
 is plain that a similar effect will be produced if the 
 supply of blood to any part remains the same, while 
 the return of it is prevented. Such obstructions are 
 most common in the heart and lungs, as a result of 
 disease in those parts. 
 
 230. Disease of the Heart. — Let us suppose that 
 the valves between the left auricle and left ventricle 
 have been inflamed, and have become so altered in 
 their shape and size that, when the heart contracts 
 to force the blood from the left ventricle into the 
 aorta, they do not completely close the opening. It 
 is plain that a portion of the blood will be forced 
 backward into the auricle. This regurgitation, as 
 physicians call it, takes place at every beat of the 
 heart, and as the auricle is in this way kept filled 
 with blood, and a sort of conflict continually takes 
 place between the current coming into it from the 
 
 * When fluid passes in this way from the interior of the b]ood- 
 vessels through their walls into the tissues outside of them, the fibrin 
 does not form a part of it. In other words, it is not \^^plasma that is 
 effused, but the serum. 
 
DISORDERS OF CIRCULATION. 177 
 
 lungs and that coming back to it from the ventricle, 
 the current in the pulmonary veins is materially 
 interfered with. In short, the blood is dammed 
 backward into the lungs. Here, then, is an actual 
 obstruction to the circulation, as much as there is 
 when we tie a string around the finger. The result 
 can be easily ascertained by following backward 
 the course of the circulation. The obstruction to 
 the exit of blood from the lungs causes the blood 
 to accumulate in that organ — in other words, pro- 
 duces a congestion there. The blood, not being 
 changed frequently enough, does not get enough 
 oxygen, and the person is obliged to breathe faster 
 in order to supply more. This we call shortness of 
 breath. The accumulation of blood in the lungs, 
 in a measure, obstructs the current of blood which 
 comes to them through the pulmonary artery. The 
 blood in the pulmonary artery being hindered in its 
 course, the right ventricle is not able to empty it- 
 self perfectly, becomes dilated, and its Avails become 
 thinned. The obstruction at this point prevents the 
 right auricle from emptying itself properly, and 
 this interferes w4th the free return-current in the 
 large veins which are connected with it. Thus the 
 flow of blood is hindered in the veins from all parts 
 of the body by the disease of one set of valves. The 
 obstruction of the venous flow brings about the 
 same results that we have observed in the con- 
 stricted fino^er. The face becomes more or less 
 livid, the lips and finger-nails bluish, and the scrum 
 of the blood passes out into the tissues around the 
 veins, causing general dropsy. This is the most com- 
 mon form of Jieart-disease, and it has been somewhat 
 minutely described, in order to show how purely 
 
1^8 ORGANS OF REPAIR. 
 
 mechanical are some of the diseases to which we 
 are subject. There are other forms of disease of 
 the valves, whose effects may be traced by those 
 curious in such things. The aortic valves, for ex- 
 ample, may be affected so as to close incompletely, 
 and allow a part of the contents of the aorta to be 
 forced back into the ventricle by the elasticity of 
 the artery every time the heart relaxes. On the 
 other hand, these same valves may be made so rigid 
 by disease that, although they close tightly enough 
 to keep the current of blood from setting back 
 through them, they do not open sufficiently wide 
 to allow a free flow through them during the heart's 
 contraction. This latter form of disease is one of 
 the most common, and gives rise to symptoms very 
 much like those of the disease which has been more 
 fully described above. Sometimes, as a result of 
 inflammation of a peculiar kind, the edges of the 
 valves have small, wart-like masses attached to them. 
 These little masses sometimes prevent the valves 
 from closing properly, and sometimes not, but they 
 always offer more or less obstruction to the circu- 
 lation. Occasionally one of these bodies becomes 
 detached from the valve by the force of the blood- 
 current, and is whirled away through the body. 
 As the current of blood in the arteries is continually 
 in the same direction, and they grow smaller and 
 smaller, such a little body at length reaches a spot 
 where the caliber of the artery is too small to let it 
 through. It plugs up the artery. This gives rise to 
 different consequences, according to circumstances. 
 Sometimes the circulation is carried on, in spite of 
 the obstruction, by other arteries which pass around 
 the point of plugging ; and sometimes the part which 
 
DISORDERS OF CIRCULATION. 
 
 179 
 
 receives its supply of blood from the affected ar- 
 tery, being thus suddenly deprived of it, dies, fall- 
 ing into the condition known as gajigrcne. 
 
 231. How Heart-Disease is detected. — All of 
 these affections of the valves of the heart, interfering 
 as they do with the free flow of the blood, give rise 
 to sounds of greater or less intensity, the varieties 
 of which are familiar to practicing physicians, and 
 indicate to them quite accurately the character and 
 extent of the disease. 
 
 232. Effect of the Coagulation of the Blood. — • 
 Whenever the surface of the body is wounded, 
 blood-vessels are necessarily severed, and, if there 
 were no means of stopping the consequent escape 
 of blood, it would not take very long for the whole 
 body to be drained. The fibrin of the blood, how- 
 ever, by its property of coagulation, serves to arrest 
 bleeding. All of the methods used by surgeons to 
 stop haemorrhage in any part of the bod}^ have for 
 their object the coagulation of the blood. 
 
 233. Conditions of Coagulation. — Blood coagu- 
 lates much more rapidly on a rough, ragged sur- 
 face than on a smooth one, and in a wound that is 
 much bruised or lacerated there is often very little 
 bleeding, even from large arteries. Instances have 
 been known in which the arm has been violently 
 torn from the body by machinerv, and the brachial 
 artery divided, with comparatively little bleeding; 
 although, if the arm were cut off, without controlling 
 the main artery, the person would die of haemor- 
 rhage in a few minutes. In a clean-cut wound the 
 hccmorrhage is often very severe from small blood- 
 vessels, and almost always needs some artiliciaJ 
 control. 
 
I So ORGANS OF REPAIR, 
 
 234. Arterial and Venous Haemorrhage. — When 
 an artery has been severed, it is not difficult for one 
 who understands the circulation to detect it. In 
 the first place, the arterial blood is of a bright scar- 
 let color, and, in the second place, it comes from the 
 vessel in jets or spurts. The blood in the veins is 
 drrk purple, and, as the veins do not pulsate like 
 the arteries, it flows from the wound in a steady, 
 uniform stream. The force with which the blood 
 issues from a cut artery is surprising. A jet from 
 one of the little arteries of a finger will spurt at 
 least a foot in a stream no bigger than a knitting- 
 needle. A vein never bleeds in spurts. In a wound, 
 however, both veins and arteries may be severed 
 and the blood mixed, although usually either the 
 arterial or venous color predominates. If the blood 
 from the wound be soaked up by a sponge or soft 
 cloth, an arterial spurt can be seen before the cut 
 fills up again with blood. 
 
 235. Natural Arrest of Haemorrhage. — If a wound 
 be left to itself, the following are the means pro- 
 vided by Nature to arrest bleeding : When an 
 artery is cut, its walls always contract somewhat, 
 so that its caliber is diminished. The elasticity 
 of the artery also draws it backward to some ex- 
 tent into the flesh. In the smallest arteries, these 
 acts are often sufficient to stop the bleeding en- 
 tirely. In every case they resist the current, make 
 it move more slowly, and so favor coagulation. 
 When a vein is cut, the walls, being thin and in- 
 elastic, collapse, the opposite sides coming in con- 
 tact and tending to obstruct the flow of blood. In 
 these ways the current of blood from all cut vessels 
 is diminished in force. The blood begins to coagu- 
 
HEMORRHAGE. l8l 
 
 late almost immediately, and this offers still further 
 resistance to the out-coming current. If the bleed- 
 ing- continues, and the blood-vessels are so drained 
 that the brain feels the lack of blood, the person 
 faints, the nervous force of the heart is diminished, 
 and in this way also the force of the flow is less- 
 ened. This is Nature's last resort, and, if the ves- 
 sels injured are so large that these means are not 
 sufficient to stop the flow, the person will bleed to 
 death. 
 
 236. Artificial Arrest of Haemorrhage ; Cold. — 
 The artificial means which we have at our com- 
 mand for arresting haemorrhage merely aim to as- 
 sist these attempts of Nature. 
 
 The application of cold to any part of the body 
 produces pallor, caused by a diminution in the sup- 
 ply of blood to the part. This is owing to the fact 
 that the stimulus of cold causes contraction of the 
 smaller blood-vessels, and so lessens the amount of 
 blood in them.- When a cut surface is exposed to 
 the air, if the vessels which have been severed are 
 small, the coldness of the air is sometimes sufficient 
 to stop the bleeding by causing a contraction of the 
 vessels. This effect can be increased by bathing 
 the wound in cold water. If this be done, however, 
 the cut surface should not be wiped or rubbed with 
 the sponge or towel, for fear that the already co- 
 agulated blood, which begins to form an obstruc- 
 tion to the flow, may be washed away. 
 
 237. Styptics. — We also have artificial means ot 
 bringing on coagulation of the blood. The sub- 
 
 * The diminution in the caliber of arteries in such cases is caused 
 by the contraction of the involuntary muscular fibers which surround 
 them, as previously explained. 
 13 
 
1 82 ORGANS OF REPAIR. 
 
 stances used for this purpose are called styptics. 
 The persulphate of iron is an exceedingly power- 
 ful one. The muriated tincture of iron is another. 
 Alum, or tannic acid, or any other astringent, pro- 
 duces the same effect. The great objection to all 
 of these substances is, that they so alter the tissues 
 with which they come in contact that the wound is 
 often hindered from healing as rapidly as it other- 
 wise would. They are mostly used when it is im- 
 possible to apply actual pressure upon the bleeding 
 vessels. 
 
 238. Compression. — Compression is the most per- 
 fect and unobjectionable method of arresting haemor- 
 rhage. This brings no outside injurious matter in 
 contact with the wounded surface, and acts merely 
 by stopping the flow temporarily until Nature has 
 time to stop it permanently. 
 
 If the wound be small, and can be covered by 
 the finger, it will generally be enough to put the 
 finger or thumb immediately on the cut and press 
 toward a bone until the bleeding stops. If the 
 wound be too large for this, pressure must be made 
 at a point outside of the wound, where the vessels 
 which are supposed to be cut are known to run.* 
 If the bleeding be venous, of course the current is 
 running toward the heart, and the pressure must 
 be made on the side farthest from that organ. If 
 the haemorrhage be arterial, the pressure must be 
 made between the wound and the heart. In the 
 
 * Or some soft, porous material, such as a towel, handkerchief, 
 sponges, or cotton cloth or batting, may be crowded into the wound 
 and held there by the hand or a bandage. This is often the easiest 
 way to apply pressure directly to the mouths of the bleeding vessels. 
 Woolen material is too rough and stiff for this purpose. 
 
HEMORRHAGE. 
 
 1 83 
 
 case of venous haemorrhage, a comparatively slight 
 pressure will generally be sufficient, as the walls of 
 the veins possess little resisting power, and are 
 readily forced into contact On the arteries, how- 
 ever, greater force is necessary, and it is sometimes 
 surprisingly difficult to fix the vessel and compress 
 it. It is to be remembered that in the limbs the 
 course of the arteries is, in the main, nearly straight 
 and lengthwise of the limb, so that all that it is ne- 
 cessary to do in case of severe arterial hsemorrhage 
 is to feel along the outer edge of the wound, an 
 inch or so from it, pressing the finger down deeply 
 until the artery is felt pulsating, and then compress 
 it against the nearest bone. 
 
 239. Permanent Arrest of Haemorrhage. — When 
 the haemorrhage has thus been temporarily arrested, 
 the pressure must in some way be kept up until 
 there is no danger of a fresh burst on its removal. 
 Nature's method of permanently arrestmg bleeding- 
 is this : It has been before stated that blood will 
 coagulate not only outside the vessels, but inside 
 themx, if its free motion is interfered with. Now, if 
 from the contraction of the vessels, or coagulation 
 of the blood which has flowed from them, or in con- 
 sequence of pressure artificially applied, or for any 
 other reason, the current of blood in the artery is 
 stopped at the severed end, the fibrin of the blood 
 begins very soon to coagulate inside the vessel, and 
 this coagulation extends from the cut end backward 
 toward the heart to a point where the circulation 
 becomes free and unobstructed, that is, to the point 
 at which some branch artery is given off from the 
 wounded one (Fig. 48). Thus the coagulum (or 
 clot) formed will vary, according to circumstances. 
 
1 84 
 
 ORGANS OF REPAIR, 
 
 Fig. 48.— Clot in 
 an artery that 
 has been tied. 
 
 from an eighth of an inch or less to an inch in 
 length. If the compression or other obstruction 
 continues long enough to allow of it, 
 this coagulum becomes firmly • at- 
 tached to the inside of the vessel, and 
 forms a plug which effectually and 
 permanently closes it, and, as the 
 wound heals, this plug and the walls 
 of the now useless artery become grad- 
 ually absorbed until a mere thread 
 remains, and even this may disappear 
 so as to leave no trace of the vessel 
 which formerly existed. But it is to 
 be considered that during the forma- 
 tion of this plug, and its attachment to 
 the walls of the vessel, it has to re- 
 ceive the impulse of the blood continually driven 
 against it seventy times a minute by the heart ; 
 and in large vessels this blow is a very strong 
 one ; so that, if the pressure be removed from 
 an artery too soon, even after this coagulum is 
 formed, the impulse of the current of blood may 
 be sufficient to drive out the plug, and bleeding 
 will begin again. This danger is absent in venous 
 hsemorrhage, and it is a general rule that if such 
 haemorrhage is once stopped it will not recur. But 
 in arteries this is a peril that must always be 
 guarded against, and surgeons accomplish what 
 they want by tying the end of the bleeding artery 
 with a string. Ligatures, made expressly for this 
 purpose, are used, and although they are finally 
 discharged from the wound with the secretions, 
 showing that they have cut through the walls of 
 the vessel around which they were tied, they re- 
 
H.'EMORRHAGE. 1 85 
 
 main long enough to accomplish the purpose.^ A 
 person's finger soon becomes exhausted by con- 
 tinual exertion in maintaining pressure, but a hga- 
 ture keeps the artery closed for several days before 
 it comes away, and thus ample time is afforded for 
 the permanent closing of the vessel in the way 
 above described. The application of a ligature re.. 
 quires special knowledge and skill, and should only 
 be attempted by a surgeon. 
 
 240. Recapitulation. — The means at everybody's 
 hand, then, for arresting haemorrhage are these : 
 
 1. The application of cold by water, ice, or air. 
 
 2. Pressure by the finger, thumb, bandage, or in 
 any way that suggests itself. 
 
 {a.) If the wound be small, pressure on the w^ound 
 itself. 
 
 (J?) If the wound be large, and the bleeding 
 from the veins, pressure on the side farthest from 
 the heart, or by plugging the wound full of some 
 soft material. If the blood comes from an artery, 
 pressure on the side nearest the heart. 
 
 (c) Pressure to be kept up until the bleeding 
 stops, or until some means can be applied to make 
 the pressure permanent. 
 
 3. Styptics or astringents. These are to be used 
 chiefly where pressure can not be applied, and after 
 the application of cold has proved insufficient. 
 
 241. Wounds of the Extremities. — Wounds of 
 the extrcDiities often bleed profuselv. Usuallv, di- 
 rect pressure on the spot of the wound will suffice 
 
 * Surgeons are now in the habit of using ligatures made of some 
 animal material, such as catgut or chamois-leather, which does not 
 irritate the wounded parts, and is gradually absorbed, so that the wound 
 can be completely closed when first dressed- 
 
1 86 
 
 ORGANS OF REPAIR. 
 
 to check it. If, however, the wounded vessel is so 
 large that it bleeds in spite of this, the main artery 
 must be compressed above the wound. It has been 
 already shoAvn that the artery is a single trunk 
 only in the upper part of each limb — i. e., from the 
 shoulder to the elbow in the arm, and from the 
 groin to the space behind the knee in the lower ex= 
 tremity. Somewhere in this course, then, the ves- 
 sel must be compressed against the bone beneath ; 
 for below the elbow and knee the artery divides, 
 and the branches are so sit- 
 uated that they can not be 
 compressed. The brachial 
 and femoral arteries — that 
 is, the arteries of the upper 
 arm and thigh — are so large 
 and strong, and receive 
 such a strong impulse from 
 the heart, besides being in 
 a measure protected by the 
 surrounding tissues, that 
 they can not be compressed 
 by the fingers to any advan- 
 tage. The best method yet 
 devised is the use of a 
 knotted Jiandker chief or o\h.^Y 
 bandage, a rope or cord be- 
 ing so small as to cut the Fig. 49.— Manner of compressing 
 
 flesh, and therefore unsuit- 
 able (Fig. 49). A handker- 
 chief should be tied loosely around the Hmb, with 
 a hard knot over the artery. Immediately under- 
 neath the knot should be placed another handker- 
 chief, folded so as to form a pad about two inches 
 
 an artery with a handkerchief 
 and stick. 
 
HEMORRHAGE. 187 
 
 wide and three long, to keep the knot from bruising 
 the flesh when the handkerchief is tightened (Fig. 
 50). The handkerchief should be loosely tied in the 
 
 Fig. 50.— Direct compression of a wound by means of what surgeons call 
 a graduated compress, made of pads of cloth, folded in different sizes, 
 with the largest one on top. 
 / 
 
 first place, so as to allow a stick or rod to be in- 
 troduced between it and the skin for the purpose 
 of twisting it. The stick or lever should be placed 
 at some distance from the compressing knot, and it 
 is better to put it on the outside of the limb, where 
 nothing will interfere with the twisting. The stick 
 is now to be twisted round and round, making the 
 handkerchief tighter and tighter and the knot press 
 down deeper and deeper, until finally the artery will 
 be compressed between the knot and the bone, and 
 the haemorrhage will cease. This method of com- 
 pression is effectual and easy of application, but of 
 course is only temporary, for such complete encir- 
 cling of a limb and entire stoppage of the circula- 
 tion produces gangrene if too long continued. 
 
 242. Fainting. — When, for any reason, the supply 
 of blood to the brain is insufficient for its nutrition, 
 the person faints. In our ordinary erect position, 
 the blood has to be driven upward by the heart for 
 a foot or more, in opposition to the force of grav- 
 i\.y. In a fainting person there is not power enough 
 to do this, and we must relieve the heart of a cer- 
 
1 88 ORGANS OF REPAIR. 
 
 tain amount of its burden. We accomplish this end 
 by laying the person flat on his back, without rais- 
 ing the head by a pillow or rest of any kind. In 
 this position the blood readily reaches the brain, 
 and that organ rapidly recovers its functions. 
 
 243. Shortness of Breath. — Shortness of breath 
 always indicates that the blood contains too little 
 oxygen. When we are short of breath from exer- 
 cise, it is due to the fact that our bodies have made 
 more waste material than usual, which the blood 
 has been unable to get rid of, and also that the oxy- 
 gen taken in from the lungs is insufficient for the 
 needs of the wasting tissues. In other words, we 
 are wearing out. Then we begin to breathe faster, 
 and thus try to get rid of more waste and take in 
 more fresh material. But, if the exercise which pro- 
 duces the excess of waste be continued, the time 
 comes when we can not breathe rapidly enough to 
 dispose of it, the body becomes limp, and we are 
 forced to rest and recover. After we have com- 
 pletely ceased our exertions the rapidity of breath- 
 ing continues for a time, making the supply much 
 greater than the waste, and gradually expelling the 
 latter from the body until the balance between the 
 two has become even again and the parts are all in 
 their natural condition. In diseases of the lungs 
 which render parts of these organs useless, such 
 as pneumonia, consumption, etc., the same effect is 
 produced. When we have only half as much lung 
 to breathe with, we have to breathe much faster to 
 make up the deficiency. 
 
PART IV. 
 ORGANS OF CO-ORDINATION, 
 
 CHAPTER I. 
 
 NERVE-SUBSTANCE. 
 
 244. Difficulty of Investigation. — The nervous sys- 
 tem is less thoroughly understood than almost any 
 other portion of the body. The difficulties of in- 
 vestigation are enormous, and its functions are so 
 intimately connected with the phenomena of con- 
 scious life that, with the exception of a few facts on 
 which all observers are agreed, the truth is buried 
 under a mass of conflicting theories, which the 
 earnest and tireless efforts of patient workers all 
 over the world are not yet able to remove. We 
 shall occupy ourselves mainly with what are ac- 
 cepted facts. 
 
 245. The Two Divisions of the Nervous Sys- 
 tem. — We have seen, in previous chapters, that cer- 
 tain operations constantly go on in our bodies, not 
 only without our willing them, but without our 
 consciousness. Such are the processes of digestion, 
 circulation, etc. Our voluntary acts, those which 
 are the result of and accompanied by conscious- 
 ness, constitute, in fact, the smallest part of what 
 goes on within us. Now, the ors^ans which are un- 
 
190 
 
 ORGANS OF CO-ORDINATION. 
 
 Fig. B. — The cerebro-spinal system of nerves. 
 
NER VE-SUBS TA XCE. 
 
 191 
 
 der voluntary control are called the organs of animal 
 life, while those which are beyond our control are 
 known as those of organic life. Corresponding to 
 these two divisions of the body are two great di- 
 visions of the nervous system — one of which has 
 charge of the organs of animal life, and is called the 
 cerebrospinal system, while the other regulates the 
 processes of organic life, and is called the sympa- 
 thetic system. The name of the former indicates the 
 fact that it comprises the cer'ebrum, or brain, and the 
 spinal cord, with the nerves proceeding from them ; 
 and the name of the latter suggests one of the prin- 
 cipal characteristics of that portion of the nervous 
 system, viz., that of inducing and regulating a sym- 
 pathy between different organs, as will be hereafter 
 explained. 
 
 246. Nervous Tissue. — Nervous tissue, wherever 
 it is found, is made up of so-called i^'Jiite matter, or 
 gray matter, or of both combined. 
 
 247. Nerve-Fibers. — The white matter is found, 
 
 en close examination, to 
 be made up oi slender 
 fibers, running parallel to 
 each other (Fig. 5 1). They 
 vary, according to their 
 situation, from the ^-gVo 
 to the i^oou of "^^ inch 
 in diameter, are nearly 
 cylindrical in shape, and 
 have for an outer layer a 
 thin, delicate membrane, 
 which serves to protect 
 the nerve-substance and retain it in shape. Just in- 
 side the membranous coyerino- is an almost trans- 
 
 FiG. 51. — Xene-fibers. 
 
192 
 
 ORGANS OF CO-ORDINATION. 
 
 parent material, which, after death, appears to co- 
 agulate and becomes whitish and slightly granular. 
 This is called the my'elin, or, by others, the white 
 substance of Schwann, from the man who first de- 
 scribed it. In the center of the whole runs a slen- 
 der thread of transparent, very finely granular mat- 
 ter, called the axis-cylinder. This latter substance, 
 in all probability, serves for the actual conduction 
 of the nervous influence, whatever it may be, and 
 the white substance of Schwann, or myelin, proba- 
 bly acts as an insulator. These distinctions be- 
 tween the different portions of a nerve-fiber are not 
 visible in the living body, but are the result of 
 changes which take place after the nerve has been 
 separated from its connections, probably from a 
 sort of coagulation. 
 
 248. Nerve-Cells. — The gray matter does not 
 consist of fibers, but of 
 cells (Fig. 52) imbedded 
 in a mass of granular mat- 
 ter. These cells vary in 
 
 ■^TTTo 01 
 
 size from -^-^ to 
 
 an inch in diameter, and 
 each contains a nucleus 
 and nucleolus, usually very 
 distinctly marked. Each 
 cell also has prolonga- 
 tions which extend from 
 its circumference in vari- 
 ous directions, and are supposed in every instance 
 to connect either with a nerve-fiber or with some 
 other cell. These prolongations vary in number 
 from one up to five or six, and, as they are traced 
 along their course with the aid of the microscope, 
 
 Fig. 52. — Nerve-cells. 
 
NERVE-SUBSTANCE. I93 
 
 they are seen to divide and subdivide until they 
 become too small to follow. It is supposed that 
 every nerve-iiber is connected with such a cell. 
 
 The ncrvc-fibcrs, above described, constituting 
 the white nerve-matter, are mere conductors of the 
 ncrvc-force. They constitute the means of commu- 
 nication between the outside of the body and the 
 nerve-centers. The nerve-cent ers, on the other hand, 
 are made up of gray matter, and are the originators 
 of nerve-force. So we see that the nervous system, 
 like the rest of the body, is made up of cells and 
 fibers, and that the essential part of the whole is 
 the cell, the fiber playing a very subordinate role, 
 
 249. Structure of the Nerves. — A nerve which 
 is large enough to be seen by the naked eye is com- 
 posed of a great number of the fibers above de- 
 scribed, lying side by side and bound together by 
 a considerable amount of connective tissue. The 
 connective tissue is greatest in amount in situations 
 where the nerve is most exposed to injury — for ex- 
 ample, in the limbs. In the brain, on the other 
 hand, and in the spinal cord, where the nerve- 
 substance is protected by a strong bony covering, 
 the amount of connective tissue is scanty and the 
 fibers are very small. 
 
 The white nerve-matter constitutes much the 
 larger part of the whole nervous system. It forms 
 the great nerve-trunks which go to the limbs and 
 to the exterior of the body in every direction, and 
 also forms the greater part of the brain and spinal 
 cord, 
 
 250. Ganglia. — The grav matter, however, forms 
 an important part of the brain and spinal cord, and 
 also of various small nerve-centers, called ganglia^ 
 
194 ORGANS OF CO-ORDINATION. 
 
 which are scattered throughout the body. In fact, 
 every collection of gray matter, which is separated 
 from other masses of gray matter by intervening 
 white matter, is called a ganglion, and so even the 
 different parts of the brain are included under this 
 name, 
 
 251. Function of Nerve-Fibers. — The function 
 of the nerve-fibers, as has been stated, is to convey 
 impressions from one end to the other. Each nerve- 
 fiber, even in the largest bundle, is completely iso- 
 lated from all others, and runs an uninterrupted 
 course from the cell, where it takes its origin, to 
 the point of its termination. At its termination, it 
 receives an impression, and this impression acts as 
 a stimulus, which produces some molecular change 
 through the whole length of the nerve, and event- 
 ually in the cell from which it comes. How this 
 communication is accomplished is not yet known. 
 Some change is produced in the nerve, which is 
 not to be detected in any way excepting by its effect 
 at the farther extremity.* In a similar manner, a 
 change originating in a nerve-cell is transmitted 
 along the fiber or fibers connected with it, and 
 manifests itself at the termination of the fiber in 
 some peculiar manner. Some nerve-fibers thus con- 
 vey impressions from the outside inward to the 
 nerve-centers, while others convey them from the 
 nerve-centers outward to the exterior of the body. 
 An intelligible illustration of this is to be seen in 
 
 * It has been found by the use of delicate instruments (galvanom- 
 eters) that there is a constant electrical current in all nerves in a state 
 of rest, supposed to be due to the nutritive changes taking place in the 
 nei-veSo When the nerve is stimulated, however, so that the natural 
 nerve-current is conveyed along the nerve, the electrical current is di- 
 minished in force. 
 
NER VE-SUBSTANCE. 195 
 
 the phenomena of ordinary sensation and muscular 
 contraction. The prick of a pin stimulates the ex- 
 tremity of a nerve-fiber, or perhaps of several The 
 current originated by this stimulus travels along 
 the course of the nerve to the nerve-center, and 
 produces what we call sensation. Then the nerve- 
 center, acted upon by this stimulus, sends out a 
 certain amount of nerve-force along another nerve- 
 fiber. This impulse follows the course of the nerve 
 down to the muscular fiber in which it terminates, 
 and there produces contraction of the muscle, and 
 removal of the part which has been pricked, out of 
 harm's way. This process, so simple to describe, 
 so plain in its gross outline, is probably a very com- 
 plex one, and it is not at all understood. When it 
 takes place, as it often does, without any conscious- 
 ness on the part of the person, it is called reflex ac- 
 tion^ because the result of the first stimulus, which 
 produced the sensation, is reflected, as it were, along 
 the second nerve to the muscle. 
 
 252. Rapidity of Nerve-Current. — It seems, at 
 first thought, as if the reaction to a nervous stimu- 
 lus were instantaneous. If the finger be hurt, it is 
 jerked away so quickly that there seems to be no 
 mterval between the injury and the action. And 
 yet it is evident that, if the received theor}- be true, 
 viz., that a current must go from the finger to the 
 brain in order to be felt, and from the brain back 
 to the muscle in order to produce muscular con- 
 traction, there must be a lapse of time. Most people 
 would probably say, however, that the nerve-force 
 must travel as rapidly as electricity, and hence the 
 time required for such a circuit would be inappre- 
 ciably short. It has been shown, however, b}' in- 
 
196 ORGANS OF CO-ORDINATION. 
 
 genious and beautiful experiments, that the nerve- 
 force does not travel over one hundred and ten 
 feet (thirty-three metres) per second, and hence to 
 go from the foot to the brain would require at least 
 one twentieth of a second, and the same to return. 
 Thus an injury to the foot would not be followed 
 by voluntary muscular contraction until at least 
 one tenth of a second had elapsed. Electricity, on 
 the other hand, travels with almost inconceivable 
 rapidityo 
 
 253. Exhaustion of Nerves. — The transmission 
 01 an impulse along a nerve-fiber not only requires 
 time, but exhausts the nerve. We have previously 
 shown that continued muscular contraction exhausts 
 the muscular fiber, and that every muscle must have 
 rest and nourishment, in order to maintain itself in 
 health and vigor. It is the same with the nerves, 
 but they recover, when exhausted, much more slow- 
 ly than the muscles, and require a longer period of 
 rest. 
 
 254. Nerve-Fibers as Conductors of Force. — 
 The fact that nerve-fibers are mere conductors of 
 nerve-force, and do not originate it, is shown by 
 cutting them in two. MS. sensation and motion 
 then cease in the portion of the body supplied by 
 the nerve which has been cut. After some time, 
 however, such injuries become healed, the cut ex- 
 tremities of the nerve unite, and the powers of sen- 
 sation and motion return. 
 
 255. Gray Matter originates Force. — It has been 
 already stated that the gray matter originates force. 
 This is indicated by the fact that all the nerve-fibers 
 end in collections of gray matter, and that in the 
 natural condition no nerve-fiber conducts an im- 
 
NER VE-SUBSTANCE. I97 
 
 pulse in either direction, inward or outward, un- 
 less it be directly connected with gray matter. 
 What the force may be which resides in the nerve- 
 cells, and what changes accompany their action, 
 we do not know, and possibly never shall know. 
 It has been often compared to electricity, and was 
 once supposed to be identical with it, but it has 
 been plainly demonstrated to be different. The 
 diminution of the electrical current during the pas- 
 sage of the natural nerve-current shows this, and, if 
 a nerve be tightly bound, the transmission of the 
 nervous impulse is prevented, while the electrical 
 current will pass through the constricted nerve 
 without appearing to meet with resistance. 
 
 256. Difference between Cerebro-spinal and 
 Sympathetic Nerves. — The cerebro-spinal nervous 
 system and the sympathetic nervous system bear a 
 close relation to the voluntar}' and involuntary mus- 
 cular tissues respectively. The voluntary muscles 
 are supplied by nerves from the cerebrospinal sys- 
 tem, and the involuntary largely by the sympatJieticy 
 and the same differences, that we have observed 
 between the two kinds of muscular tissue in their 
 manner of contraction, are also found in the two 
 systems of nerves. A stimulus applied to any por- 
 tion of the cerebro-spinal system produces an im- 
 mediate response, while irritation of any portion of 
 the sympathetic system only produces an effect after 
 the lapse of an appreciable time. 
 
 The only portion of the nervous system over 
 which we have any control whatever, and which 
 stands in any relation to our consciousness, is the 
 cerebro-spinal system (Fig. 53). This system, con- 
 stituting by far the greater bulk of our nervous ap- 
 14 
 
198 
 
 ORGANS OF CO-ORDINATION. 
 
 paratus, comprises the brain and the spinal cord, 
 together with all the nerves which take their origin 
 
 3S^erves to ^_ 
 left arm. • - — ^ 
 
 Nerves to 
 front of 
 left leg. 
 
 Nerves to 
 back of 
 left leg. 
 
 Nerves to 
 right arm. 
 
 Nerves to 
 front of 
 right leg. 
 
 Nerves to 
 back of 
 right leg. 
 
 Fig. 53. — Brain and spinal cord, with the thirty-one pairs of spinal nerves. 
 
 in these organs. The brain is a very complex or^ 
 gan, being composed of several different ganglia, 
 each of which has its own peculiar functions. In 
 describing the nervous system it will be convenient, 
 therefore, to begin with the sympathetic system, as 
 being the simplest in its structure and functions. 
 
CHAPTER II. 
 
 THE SYMPATHETIC SYSTEM. 
 
 257. Structure of the Sympathetic System. — The 
 
 sympathetic system consists of a double chain of nerv- 
 ous ganglia in the head, neck, and trunk, sending 
 fibres to various organs and to the blood-vessels 
 throughout the body (Fig. 54). The arms and legs 
 
 Fig, 54. — The sympathetic system of uerves in the truiik. 
 
200 ORGANS OF CO-ORDINATION. 
 
 are organs of animal life, and are supplied with cere- 
 bro-spinal nerves. The ganglia of the sympathetic 
 vary very much in size, some being only visible with 
 the microscope, and others as large as a pea, or, 
 rarely, even larger. They are composed, as has 
 been said, of gray nerve-matter, and are connected 
 with each other and with the cerebro-spinal nerves 
 by means of communicating fibers. Some of these 
 fibers are of the ordinary white matter, while others 
 are transparent and grayish in color, and appear to 
 consist of an axis-cylinder alone, without any sur- 
 rounding myelin. The sympathetic ganglia all lie 
 very deep in the cavities of the body, in the vicinity 
 of and surrounding the important organs,"^ whose 
 functions they control, and it is very difficult to get 
 at them for purposes of experiment. The conse- 
 quence of this is, that very little has been learned 
 about the real action of the sympathetic system, 
 and many of its functions can at present only be 
 conjectured. 
 
 258. Sluggish Action of Sympathetic Nerves. — 
 The sympathetic nerves have been proved to be 
 capable of conveying both sensory and motor im- 
 pulses ; but these properties are very slow in mani- 
 festing themselves, in marked contrast to the behav- 
 ior of the cerebro-spinal nerves. If the extremity 
 of a sympathetic nerve be irritated, it is only after 
 a considerable time that the nervous center is af- 
 
 * The large sympathetic ganglia, called the solar plexus, or the 
 semi-lunar ganglia (from their shape), lying behind the pit of the stom- 
 ach, constitute what has been sometimes called the abdominal brain. 
 A blow in this region is very dangerous, for, if it is powerful enough to 
 paralyze these ganglia by the shock, it is more certain to cause instant 
 death than the severest blow on the head. 
 
THE SYMPATHETIC SYSTEM. 2OI 
 
 tected, and the reflex motion is very slow in its 
 appearance. This fact is illustrated in the inflam- 
 mations and congestions of internal organs. The 
 sympathetic system mainly furnishes the ner\'Ous 
 supply of the organs of digestion and secretion. If 
 any irritation, like the cold air of a draught for in. 
 stance, affects the body, the result, such as internal 
 congestions, etc., only appear after some time has 
 elapsed. i\n exposure to injurious influences may 
 produce a serious disease through the sympathetic 
 system, and yet the disease may not declare itself 
 for ten or fifteen or even twenty-four hours after 
 the exposure, 
 
 259. Contraction of the Pupil. — Various familiar 
 phenomena show this sluggish action of the sympa- 
 thetic nerves. One of the most obvious is the con- 
 traction of the pupil of the eye under exposure to 
 Hght. When a strong light is thrown into the eye 
 the pupil grows smaller and shuts out the excess of 
 light. On the other hand, when the supply of light 
 is diminished, the pupil enlarges so as to adm.it 
 more. Now, these changes in the size of the pupil 
 take place very slowly. When we go from a light 
 room into a dark one it is several seconds, some- 
 times a minute, before we can see anything, simply 
 because the pupil does not admit enough light and 
 requires time to enlarge sufficiently. When we go 
 from a dark room to a very light one we are daz- 
 zled ; the pupil is too large and admits too much 
 light, and we are obliged to shade our eyes until 
 contraction has taken place. These phenomena are 
 the result of impressions made on the sympathetic 
 system, and serve as an excellent illustration of the 
 slowness and precision of its action, as well as of the 
 
202 ORGANS OF CO-ORDINATION. 
 
 fact that its functions are entirely beyond our con- 
 scious control."^ 
 
 260. Effect of dividing a Sympathetic Nerve. — 
 One of the most remarkable facts relating to the 
 sympathetic system was discovered by the cele- 
 brated physiologist, Bernard, and has been sub- 
 stantiated since by many careful observations on 
 persons in whom different sympathetic nerves have 
 been incapacitated by disease or severed during a 
 surgical operation. If, for instance, the sympathetic 
 nerve running to the ear be divided, the ear be- 
 comes red and hot, and the blood-vessels are seen 
 to be enlarged and much fuller of blood than they 
 usually are. There is no stagnation of the circula- 
 tion, and, after the lapse of a sufficient time, three 
 or four weeks, if the divided ends of the nerve 
 unite, the ear returns to its natural condition. If, 
 after the nerve has been divided, as above, while 
 the ear is in its red and hot condition, the end of 
 the nerve nearest the ear be irritated by a galvanic 
 current, the blood-vessels contract, the unusual 
 amount of blood is expelled from them, and the ear 
 resumes its ordinary temperature and color. If the 
 cause of irritation be removed, the redness and heat 
 return. These facts seemed to indicate that the 
 supply of blood in a part was regulated by the 
 sympathetic system of nerves, a supposition which 
 has been confirmed many times over. 
 
 * The iris — i. e., the muscular curtain surrounding the pupil — is 
 supplied with nerves from the cerebro-spinal system as well as from 
 the sympathetic. The relative functions of the two sets of fibers are 
 not well understood, but the sluggish and involuntary character of the 
 changes in the size of the pupil shows that the influence of the sympa- 
 thetic nerves predominates. 
 
THE SYMPATHETIC SYSTEM. 203 
 
 261. Influence of the Sympathetic Nerves on Se- 
 cretion. — It has been found that, if the sympathetic 
 nerve supplying one of the salivary glands be di- 
 vided, an increased supply of blood takes place and 
 increased secretion by the gland follows. The sub- 
 maxillary gland being treated thus, an increased 
 ilv)\v of saliva takes place. A similar effect is pro- 
 duced by galvanic irritation of the nerve of taste. 
 Any savory substance in the mouth, then, irritat- 
 ing the nerve of taste, gives rise to a reflex action 
 through the nerves supplying the salivary glands, 
 and produces a flow of saliva. This is what we 
 call " feehng the mouth water." The same ef- 
 fect may even be produced by purely emotional 
 causes, as the mere sight of an appetizing article 
 of food. 
 
 262. Effect of Emotion on the Sympathetic 
 Nerves. — Blushing is another phenomenon depend- 
 ing on the control of the sympathetic nerves over 
 the blood-vessels. The emotion of shame produces 
 a temporary paralysis of the sympathetic nerves, 
 and gives rise to the same effects as a division of the 
 nerve. Blood rushes to the superficial blood-vessels 
 and they become redder and hotter than they ordi- 
 narily are. The blush is more evident in the cheeks 
 than elsewhere, because the skin is thinner there, 
 and the blood-vessels more numerous ; but the 
 blush extends, in reality, much more widely than is 
 commonly supposed, and covers a large portion of 
 the surface of the body. The peculiar character- 
 istics of the svmpathetic svstem are to be plainly 
 discerned in the blush. It is not instantaneous, but 
 comes on slowly after an indignity, gradually rises 
 to its greatest height, and then gradually disap- 
 
204 ORGANS OF CO-ORDINATION. 
 
 pears. It is also beyond the control of the will. 
 If a person really feels the emotion, he can not re- 
 strain the blush. The only means of preventing it 
 lies in such a constant schooling of the mind that 
 feelings of shame, modesty, insulted dignity, etc., 
 shall not be felt. When a person has arrived at 
 this point of self-control he will not blush. But who 
 would wish to purchase exemption at such a price ? 
 Many persons are ashamed of blushing, but who 
 would be ashamed of being ashamed? The two 
 can not be separated, and one who has lost the sense 
 of shame entirely has lost much of what commends 
 us to the sympathy and respect of our fellows. 
 
 263. The Vaso-motor Nerves. — The nerves 
 which thus control the supply of blood to the 
 blood-vessels are called the vaso-motor nerves. They 
 have been already referred to in another part of 
 this book. They have received the name of vaso- 
 motor because they control the motion of the walls 
 of the vessels {vasd) producing contraction or relax- 
 ation. Although they are chiefly of the sympa- 
 thetic system, they receive fibers from the cerebro- 
 spinal system. The two systems are not entirely 
 distinct from each other, but there are certain func- 
 tions in which they are so widely different that we 
 can say with certainty this action belongs to the 
 cerebro-spinal system, or that one to the sympa- 
 thetic ; while between these extremes are all sorts 
 of gradations, so that in many cases we are unable 
 to distinguish the characteristics of either system, 
 and must say of them that we do not know how 
 they are produced or that both systems probably 
 unite their functions. 
 
 264. Influence of the Sympathetic System on Di- 
 
THE SYMPATHETIC SYSTEM. 205 
 
 gestion. — The process of digestion is presided over 
 and regulated mainly by the sympathetic nervous 
 system. The introduction of food into the stomach 
 stimulates the nervous ganglia in the abdomen, and 
 through their influence is followed by all the phe- 
 nomena of secretion, muscular movements, and ab- 
 sorption, which have been shown to accompany 
 and form a part of the process of digestion. All of 
 these phenomena are beyond our control, but, as 
 has been shown in the case of the blush, the nervous 
 supply of the S3^mpathetic is favorably or unfavor- 
 ably affected by strong emotions. And it is through 
 these ganglia and their connections that anger, fear, 
 or other depressing emotions, produce vSuch an in- 
 jurious effect on the digestive organs during and 
 after a meal. 
 
 265. Effect of Cold on the Sympathetic System. — 
 It is through the reflex action of these nerves, also, 
 that haemorrhage can often be checked by the ap- 
 plication of cold, and that inflammation of internal 
 organs may result from the same cause. The mu- 
 cous membranes, for the same reason, seem to be 
 more exposed to such inflammations than any other 
 portion of the organism. Hence, exposure to a cold 
 draught is very apt to bring on such a disorder. In 
 one person it may affect one mucous membrane, in 
 another another, according to the relative condition 
 of the membranes at the moment. After such an 
 exposure, one person ma}^ have a severe cold in the 
 head, another a bronchitis, another a sore throat, 
 another a diarrhoea or inflammation of the mucous 
 membrane of the intestines.^ All of these results 
 
 * Many persons, instead of catching cold in the nose or throat after 
 exposure, have their bowels affected, and the resulting catarrh causes a 
 
2o6 ORGANS OF CO-ORDINATION. 
 
 are beyond our control, and the only way to pre- 
 vent them is to keep out of danger. When a person 
 is in health, food introduced into the stomach will 
 inevitably be digested, whether he wills it or not, 
 and, if he undergoes certain exposures, he will take 
 cold, in like manner, whether he wills it or not.* 
 
 266. Exhaustion of the Sympathetic System. — 
 As the sympathetic system is so intimately con- 
 nected with the processes of nutrition, and indeed 
 with all the functions of those organs which main- 
 tain us in life, without our consciousness, it is evi- 
 dent that it should be well taken care of and nothing 
 done to cripple it. We have, then, to bear in mind 
 that nerves require rest as w^ell as any other part of 
 the body, that they easily become exhausted, and 
 that they require a longer period for recuperation 
 than the muscles do. The surest sign, perhaps, of 
 exhaustion of the sympathetic system will be found 
 
 diarrhoea. When a person is specially liable to this affection, he should 
 wear a thick flannel bandage around the abdomen, which will furnish 
 almost entire relief from such attacks. 
 
 * A cold is generally the result of the sudden chilling of some part 
 or the whole of the surface of the body. The first effect of such a chill 
 is to contract the blood-vessels on the surface and overfill those that lie 
 deeper, and thus to cause congestions of the internal organs. Such an ef- 
 fect seems to be especially apt to follow a cold draught striking the back 
 of the head or neck or the ankles. Now, active muscular exercise tends 
 to drive the blood to the surface, and is therefore a natural preventive 
 of colds. It tends to keep the blood at the surface, where a conges- 
 tion will be relieved by perspiration, and prevents its accumulation in 
 the deeper organs, where it is more likely to cause trouble. If expos- 
 ure to cold, therefore, can not be avoided, we must keep up a brisk 
 circulation by physical exercise. Wet clothing should be changed for 
 dry as soon as possible, for so long as it remains in contact with the 
 body it absorbs a great amount of heat from it and keeps up a constant 
 chilling of the surface. When a person is not engaged in physical ex- 
 ertion, he should avoid draughts. 
 
THE SYMPATHETIC SYSTEM. 20 7 
 
 in failure of nutrition. If a person grows thin and 
 pale and languid, notwithstanding a good supply 
 of food, or if his food be not appropriated by the 
 body — in short, if his nutrition become impaired, 
 and no organic disease be discoverable — it is prob- 
 ably the result of nervous exhaustion, and means 
 should be taken to relieve the overtasked orgfans. 
 Rest will accomplish wonders in many cases of ill- 
 ness, especially where there is no disease of any 
 particular organ to be detected. 
 
CHAPTER in. 
 
 THE SPINAL CORD. 
 
 267. Structure of the Spinal Cord. — The spinal 
 cord is that portion of the nervous system which 
 Hes within the spinal canal. It extends from the 
 junction of the spinal column with the skull, down 
 to the loins, and is about a foot and a half long- and 
 a little less than half an inch in diameten It weighs 
 about an ounce and a half. It does not occupy the 
 whole spinal canal, but the space around it is filled 
 with membrane, blood-vessels, and nerves. At its 
 upper extremity it passes into the brain, and at its 
 lower, just below the last rib, it divides into a bundle 
 of small nerves, presenting very much the appear- 
 ance of a tassel at the end of a thick cord."^ 
 
 The spinal cord consists partly of white and 
 partly of gray matter. The gray portion occupies 
 the central portion of the cord, and is arranged 
 somewhat in the form of the letter H, Avith the two 
 upright marks curving outward at both ends (Fig. 
 55). The remainder of the cord, in which this gray 
 substance is imbedded, is composed of white matter. 
 
 The spinal cord, throughout its whole length, is 
 divided by fissures, one of which extends from be- 
 
 * This part of the spinal cord is called the caud'a equi'na — i. e., the 
 horse's tail, which it somewhat resembles. 
 
THE SPINAL CORD. 209 
 
 fore backward, and the other from behind forward, 
 the two nearly meeting. They are, however, sepa- 
 rated, and the halves of the cord kept in communi- 
 cation by a bridge of gray matter, which passes over 
 from one to the other, forming the cross-line of the 
 letter H. 
 
 268. The Spinal Nerves. — The spinal cord sends 
 out nerves through its whole course. With the ex- 
 ception of the head and face, all the muscles and the 
 skin of the body receive their nervous supply from 
 this source. These nerves, thirty-one pairs in all, 
 issue from the spinal column between the vertebrae 
 through small openings. 
 
 269. Properties of the Spinal Nerves. — All parts 
 of the body, which are supplied Avith spinal nerves, 
 are endowed with two remarkable properties, sen- 
 sation and motion. As long as the nervous supply 
 remains in a natural and healthy condition, any por- 
 tion of the body feels, and any portion can be moved 
 from one place to another. These movements are 
 sometimes voluntary and sometimes we are entirely 
 unconscious of them, and it is only Avithin a few 
 years that physiology has been able to offer any ex- 
 planation whatever of these facts. 
 
 270. Sensation and Motion. — When we consider 
 attentively the property of sensation, we find that 
 there are tAvo great divisions of it, easily distin- 
 guishable and easily demonstrated, viz., sensibility 
 to pain and ordinary sensation. When a person is 
 brought under the influence of an anaesthetic, the 
 sensibility to pain disappears before ordinary sen- 
 sation is lost, and even while the individual is still 
 conscious. In slight surgical operations this fact 
 is often strikingly manifest. A tooth may be pulled, 
 
2IO ORGANS OF CO-ORDINATION. 
 
 and the patient be conscious of every step of the 
 proceeding, without feeling the slightest pain. Nar- 
 cotics, too, may relieve pain, vv^hile the person who 
 has taken them remains perfectly in possession of 
 his senses. Physiologists have made other discrim- 
 inations of sensation, which it is not necessary to 
 mention here. 
 
 The phenomena of motion are familiar, and re- 
 quire no separate consideration. 
 
 271. Effect of dividing a Nerve. — If one of the 
 spinal nerves be disabled, sensation and motion 
 are abolished in the portion of the body supplied 
 by that nerve. This shows that sensation and mo- 
 tion are both conveyed in the same nerve. But 
 here a difficulty arises. Sensation implies the pas- 
 sage of a nerve-current from without inward, to- 
 ward a nerve-center; whereas motion implies the 
 passage of a current from within outward, from the 
 nerve-center to the muscle. Can both these cur- 
 rents be transmitted at the same time, or can the 
 axis-cylinder of the nerve-fiber be used for the pas- 
 sage of the nerve-current in either direction accord- 
 ing to circumstances ? This is the problem which 
 waited until this century to be solved. The sim- 
 plest explanation has been found to be the correct 
 one. As every nerve is made up of many fibers, it 
 would be natural to suppose that some of these 
 fibers might serve as conductors of sensation, and 
 others of motion. This was made all the more 
 probable by the fact that, in many forms of dis- 
 ease, it was seen that the power of sensation might 
 be abolished, while that of motion remained ; or, on 
 the other hand, the pov/er of motion might be par- 
 alyzed, while that of sensation remained unimpaired. 
 
THE SPIXAL CORD. 21 1 
 
 And, in fact, the above explanation of these phe- 
 nomena was found to be correct. The first who 
 demonstrated this appears to have been Sir Charles 
 Bell," although Magendie f has strong counter- 
 claims to the honor. The observations by which 
 the truth was established were decisive, and have 
 been often repeated by other physiologists. They 
 are the following : 
 
 272. The Roots of the Spinal Nerves. — The spi- 
 nal nerves do not take their origin from the spinal 
 cord as single trunks, but each one arises by two 
 roots. One of these roots is formed of fibers com- 
 ing from the anterior portion of the cord, and is 
 called the anterior root ; the other is formed by 
 fibers from the posterior portion of the cord, and 
 is called the posterior root ; the latter, at a short dis- 
 tance from its source, passes through a small gan- 
 glion of gray matter. These two roots, anterior 
 and posterior, approach each other and unite in a 
 single cord just before leaving the spinal canal. 
 This cord, therefore, contains fibers from both por- 
 tions of the spinal cord, and, after running a short 
 distance, it again divides into two nervous trunks, 
 one of which supplies the front of the body and the 
 other the back. 
 
 273. Division of the Anterior Root. — When the 
 anterior root of a spinal nerve is disabled (Fig. 55), 
 the portion of the body supplied by the nerve of 
 which this particular root forms a part, loses its 
 
 * Sir Charles Bell, a distinguished Scotch anatomist, physiologist, 
 and surgeon (1774-1842), Professor of Surgery in the University of 
 Edinburgh. 
 
 f Fran9ois Magendie, a celebrated French physiologist (1783-1855), 
 Professor of Anatomy in the College of France. 
 
212 ORGANS OF CO-ORDINATION. 
 
 power of motion, but preserves its sensibility unim- 
 paired. If the portion of the body supplied by this 
 
 <I0R ROOT 
 
 Fig. 55. — Cross section of spinal cord and roots of spinal nerves, with ante- 
 rior root cut. 
 
 nerve be pinched or pricked, there are evident 
 signs of pain, and the irritation is clearly perceived, 
 but there is entire inability to move the muscles of 
 the part. If, now, the ends of the nerve be irri- 
 tated, the following results are obtained : On irrita- 
 tion of the end nearest the part supplied by the 
 nerve, the muscles of that part become strongly 
 contracted, or convulsed, while there is no indica- 
 tion of any sense of feeling whatever. If the end 
 nearest the spinal cord be irritated, no effect what- 
 ever is produced. There are no convulsive move- 
 ments of the muscles, and no indication of sensa- 
 tion. This seems to show that, in the fibers of the 
 anterior root, the nervous impulse is transmitted 
 from within outward, and gives rise to the phe- 
 nomena of motion, while they have nothing to do 
 with sensation. 
 
 274. Division of the Posterior Root. — If, now, 
 instead of the anterior root, th.Q posterior root is the 
 injured one (Fig. 56), we find that the part supplied 
 by the nerve has lost sensation, but retains the 
 power of motion. If it be pinched, pricked, or in- 
 jured in any way, no effect is produced, and no 
 notice is taken of it whatever. This shows that 
 
THE SPINAL CORD. 
 
 213 
 
 sensation in the part is abolished. If, now, the ends 
 of the root be irritated, we find the following- re- 
 sults : On irritation of the end nearest the part, no 
 effect whatever is produced. If, on the other hand, 
 the end nearest the cord be irritated, there are im- 
 mediate indications of pain, and the muscles sup- 
 
 Fig. 56. — Cross section of spinal cord and roots of spinal nerves, with pos- 
 terior root cut. 
 
 plied by the injured nerve are still able to contract 
 as powerfully as ever. This shows that the p.ower of 
 motion has not been interfered with by the injury, 
 and it also shows that, in the posterior roots of the 
 spinal nerves, the nervous impulse is transmitted 
 from without inward, and has to do with sensa- 
 tion. 
 
 275. Two Kinds of Fibers in Each Nerve. — The 
 anterior roots, then, are composed of motor fibers, 
 and the posterior roots of sensory fibers. The two 
 unite, as has been shown, to form a single cord, 
 which afterward divides again to supply the front 
 and back of the body. Every spinal nerve in this 
 way is made up of both sensory and motor fibers, 
 or fibers which convey sensation and fibers which 
 convey motion ; and thus, from the constitution of 
 the nerve, it is easy to see how the powers of sen- 
 sation or motion can be abolished separately, one 
 remaining intact while the other disappears. 
 
 276. Relation of the Spinal Cord to the Brain. — 
 
 15 
 
214 ORGANS OF CO-ORDINATION. 
 
 These properties of sensation and motion have been 
 considered only in their relations to consciousness. 
 The sensations have been spoken of as felt, and the 
 movements as voluntary. In order for this to be 
 so, there must be some connection between the 
 nerves and the brain, for consciousness has its seat 
 in the latter, as we shall hereafter see. And in fact 
 it has been proved that the nerve-fibers, after enter- 
 ing the spinal cord, pass upward in its interior 
 toward the brain. It is probable that the white 
 matter of the cord is largely composed of fibers 
 w^hich connect the brain in this way with the exte- 
 rior of the body. 
 
 As the nerve-fibers approach the brain, however, 
 at the very summit or upper extremity of the spi- 
 nal cord, they cross over from one side of the cord 
 tc the other, the fibers from the right side passing 
 over to the left, and those from the left going over 
 to the right. The crossing of the motor fibers only 
 takes place at this point, while the sensitive fibers 
 cross to the opposite side of the cord soon after 
 joining it. The consequence of these facts is, that 
 the right side of the body comes into direct com- 
 munication with the left side of the brain, and the 
 left side with the right brain. An injury to the 
 brain, therefore, on either side, produces paralysis 
 of the opposite side of the body. An apoplexy* 
 affecting the right side of the brain brings on paral- 
 ysis of the left side of the body ; and conversely, if 
 we see a person whose left side is paralyzed, we 
 
 * Apoplexy, from the Greek, meaning a sudden stroke. It is caused 
 by the giving way of some blood-vessel in the brain, and the blood 
 escaping into, compressing, and tearing apart the delicate nerve-tissue, 
 causes paralysis and often entire unconsciousness, or death. 
 
THE SPINAL CORD. 215 
 
 look for the injury which has caused it on the right 
 side of the head. 
 
 277. Sensations referred to Extremity of Nerve. 
 — It has already been said that the nerve-fibers act 
 merely as conductors of an impulse, and do not 
 themselves originate nervous force. In consequence 
 of this, an injury to any portion of a nerve always 
 produces the same effect as if it were at its extrem- 
 ity. The pain which results from any impression 
 on a nerve-fiber is always referred by the nerve- 
 center which receives it to the termination of that 
 particular nerve. And this fact clearly explains 
 many things that once were not understood. The 
 ulnar nerve furnishes a good illustration of this. At 
 the inside of the back of the elbow are two bony 
 projections, with a hollow canal between them. At 
 the bottom of this canal, not far below the skin, runs 
 a large nerve called the ulnar nerve, because it sup- 
 plies the ulnar side of the fore-arm and hand. If 
 this nerve be pressed or injured in any way, a tin- 
 gling sensation is felt in the little finger and the ad- 
 joining side of the ring-finger, the parts supplied by 
 this nerve." Striking examples of the same phe- 
 nomenon are often seen in persons who have lost 
 limbs by amputation. If the end of the nerve which 
 remains in the stump be irritated in any way, as by 
 the contraction of the scar, the person feels the irri- 
 tation precisely as if it were in the lost limb. If any 
 person's arm were cut off, for instance, just below 
 
 * The ulnar nerve supplies the little finger, the adjoining side of 
 the ring-finger, and that side of the hand as far as the wrist. Pressure 
 upon it, therefore, interferes with the nerv'ous supply of those parts, 
 and thjy tingle and become numb. The queerness of the sensation 
 produced has caused this nerve to be commonly known as the crazy- 
 bone, or the funny-bone, although it is not a bone at all. 
 
2i6 ORGANS OF CO-ORDINATION. 
 
 the elbow, and the stump of the ulnar nerve were 
 irritated, he would feel the tingling sensation in the 
 little and ring fingers of his hand just as much as if 
 the hand were still attached to the arm. The sen- 
 sation is precisely the same, and can only be cor- 
 rected by the sense of sight or by the individual's 
 own memory or reason. It is this fact which has 
 given rise to the numerous accounts of persons who 
 have felt people maltreating their amputated limbs, 
 when they perhaps were already decayed, or w^ere 
 hundreds of miles away. 
 
 278. Reflex Action of the Spinal Cord.— All the 
 phenomena which have been described might occur 
 just as well if the spinal cord were merely a large 
 bundle of white fibers running down from the brain, 
 and sending out branches to different parts oi the 
 body. It has, however, a considerable amount of 
 gray nerve-matter in its interior, and, as we have 
 seen that this form of nerve-matter originates force, 
 we are prepared to infer that the spinal cord can 
 originate movements and receive sensations without 
 any connection with or dependence on the brain. 
 And this is found actually to be the case. If the 
 head of a frog be cut entirely off, leaving the body 
 otherwise uninjured, sensation and motion are still 
 manifested in the trunk and limbs. If the toe be 
 pinched, the leg will be drawn up out of the way. 
 This is the same effect that is produced when the 
 animal is entire, with this exception : there is no 
 attempt to escape from further injury. In other 
 words, there is no brain-action, no reasoning. The 
 irritation sends a nerve-current along the sensory 
 nerve to the spinal cord. There it produces cer- 
 tain changes in the cells of the gray matter, and 
 
THE SPINAL CORD 217 
 
 from them another current is sent outward along 
 the motor nerve to the muscles, and movement re- 
 sults. If the nerve be severed, no such effecc can 
 be produced. If the spinal cord be destroyed, the 
 nerves remaining intact, no such effect will occur. 
 These facts show that the cord itself has the prop- 
 erty of receiving sensations and sending out motor 
 impulses. This action of the spinal cord, by which 
 it produces a movement in response to and in con- 
 sequence of a sensation, is called reflex action. 
 
 279. Diseases of the Spinal Cord. — Experiments 
 like the above, of course, can not be performed on 
 human beings, but the course of nature often per- 
 forms them for us. Diseases are not uncommon in 
 which the spinal cord is completely cut across in 
 some portion of its length, so that there is no nerv- 
 ous communication between the brain and that part 
 of the body below the seat of disease or injury. 
 In such cases we have paralysis of the kind called 
 by phj'sicians paraplegia — i. e., the lower portion of 
 the body is no longer under control of the brain, 
 and no longer capable of voluntary movements. It 
 is also entirely beyond the domain of conscious- 
 ness; injuries to the paralyzed part cause no sensa- 
 tion in the brain. The separation of such a part of 
 the body from all relation to consciousness, whether 
 of sensation or of motion, is as complete as if it 
 formed part of another body. Notwithstanding 
 this fact, we often find the spinal cord below the 
 seat of injury to be in the same condition as that of 
 the decapitated frog. If the disease or injury has 
 been confined to a particular part of the cord, and 
 the portion below, with its nerves, be still in a 
 healthy condition, excepting that it is separated 
 
2i8 ORGANS OF CO-ORDINATION, 
 
 from the brain, a stimulus applied to any of the 
 nerves will produce a response which is immediate 
 and decided. A person in this condition looks on 
 and sees his feet pinched, or pricked, or burned, 
 and sees the irritation followed by violent convul- 
 sive kicks and thrusts of the limbs, without the 
 slightest knowledge of what is going on, excepting 
 what he receives through the sense of sight. 
 
 280. Automatic Actions. — Certain actions, which 
 are at first voluntary, and only accomplished by 
 great effort, become, after a time, so natural and 
 easy, that they seem to be carried on unconscious- 
 ly, through the action of the spinal cord. Thus, in 
 the act of walking, a harmonious action of several 
 muscles is required to keep the balance, an action 
 which is at first learned only after prolonged and 
 incessant effort. In after-life it becomes so easy as 
 to be carried out without consciousness, as has been 
 often shown in the case of soldiers, who have con- 
 tinued to walk in the ranks and keep up with their 
 comrades on the march while fast asleep. 
 
CHAPTER IV. 
 
 THE LRAIX. 
 
 281. The Brain. — The brain and the cerebrum are 
 often spoken of as if they were convertible terms. 
 But this is not correct. The brain includes all that 
 part of the nervous system which lies within the cav- 
 ity of the skull. This great mass of nervous matter 
 is made up of several distinct ganglia, which, to be 
 
 sure, are connected with 
 one another and interde- 
 pendent, and yet each of 
 them has its own particular 
 function which the others 
 have not (Fig. 57). The cere- 
 brum is merely one of these 
 ganglia, and, although the 
 highest in the scale as re- 
 gards the character of its 
 functions, it being the gan- 
 glion which principallv 
 
 Fig. 57. — Dias^am showing the . . ^ . -^ 
 
 position of the nervous con- gi^cs man his pre-cmmence 
 ters in the head. ovcr the lowcr auimals, it is 
 
 one of the least important 
 as regards the mere preservation of life. In many 
 of the lower animals it can be entirely removed, and 
 the animal will live for months afterward. In the 
 
220 
 
 ORGANS OF CO-ORDINATION. 
 
 human being it is so plentifully supplied with blood- 
 vessels that, if its removal should be attempted, the 
 person would die of haemorrhage. This has been 
 the invariable result of experiments on the higher 
 kinds of animals, as the dog or horse. But there is 
 no doubt that, if the cerebrum could be removed 
 without interfering with the circulation of the blood, 
 even a human being would continue to live with- 
 out it. 
 
 282. Structure of the Cerebrum. — The cerebriiin 
 (Fig. 58) is the largest part of the brain, forming as 
 
 yi'lG, 58. — Under surface of the brain, showing' the great complexity of its 
 Structure. At the lower part of the cut is the cerebellum. 
 
THE BRAIN. 
 
 221 
 
 it does about nine tenths of the whole mass within 
 the skull. It consists of two halves, called hcnii- 
 spkcrcs, the dividing fissure running from the front 
 of the head to the back ; but the halves are not en- 
 tirely separated. On their under side, a bridge or 
 mass of white fibers runs from one to the other, and 
 serves as a means of nervous communication be- 
 tween them. The cere- 
 brum is composed of both 
 white and gray matter, the 
 latter being spread over 
 the surface, and the former 
 filling up the interior, and 
 forming the greater por- 
 tion of the mass (Fig. 59). 
 The arrangement of 
 the nerve-matter of the 
 cerebrum is very peculiar. 
 It is formed into folds and 
 wrinkles, somewhat like 
 the meat of an English 
 walnut. These folds are 
 called the convolutions of 
 the brain, and, as the gray 
 matter follows closely the 
 dipping of the surface be- 
 tween the convolutions, it 
 is evident that the amount 
 of gray matter is much 
 Sfreater than it would be 
 if the surface of the brain 
 were smooth. 
 It has been found by experiment that the nerve- 
 matter composing the cerebrum is insensible to 
 
 Fig. 59. — Section of thebrain, show- 
 ing the arrangement of the gray 
 and white substance. 
 
222 ORGANS OF CO-ORDINATION. 
 
 ordinary irritation. Either the gray or the white 
 matter may be cut, pricked, burned with fire or 
 caustic acids, without producing any sensation. 
 What, then, is the function of the cerebrum ? 
 
 283. Function of the Cerebrum. — It is now ac- 
 knowledged by all who have paid any attention to 
 the subject, that the cerebriun is the organ of thought. 
 It is in this part of the brain that all ideas have their 
 origin, and that all processes of reasoning take place. 
 The evidence of this is indirect, but very conclusive, 
 and may be briefly stated as follows : 
 
 284. Intelligence increases with Increase in Size 
 of the Cerebrum. — The cerebrum increases in size 
 in animals as we pass from the lower forms to the 
 higher. The superiority of one animal over another 
 in the scale of life depends mainly upon what we 
 call intelligence. Now, we find that the intelligence 
 of animals appears to increase in the same ratio that 
 the size of the cerebrum increases in proportion to 
 the rest of the body. In the fish, the cerebrum is 
 very small, and his intelligence is very low. In the 
 reptiles, the cerebrum is somewhat larger, and their 
 intelligence as a class greater. In birds, the relative 
 size of the cerebrum is considerably increased, and 
 their intelligence is proportionally and noticeably 
 higher. From birds we pass to quadrupeds, and 
 here is a great increase in the size of the cerebrum, 
 and a correspondingly finer intelligence. As we go 
 up in the scale of quadrupeds, we find the size of 
 the cerebrum increasing faster than the size of the 
 body does, until, in the elephant, we find a brain 
 weighing eight or ten pounds. The elephant and 
 the whale are the only animals whose brains are 
 larger than man's, and even their immense brains are 
 
THE BRAIN. 22^ 
 
 much smaller relatively to the size of their bodies. 
 The human brain varies in weight in different persons, 
 but its average weight is fifty ounces, or about three 
 pounds. These facts, then, seem to show a relation- 
 ship between the cerebrum and the quality of intelli- 
 gence, for the difference in weight of different brains 
 is mainly due to the varying size of the cerebrum. 
 
 285. Size of Human Brains. — When we examine 
 different brains among human beings, we find the 
 same general law holding good. Other things be- 
 ing equal, a larger brain signifies a greater mind. 
 Thus the brain of Cuvier,* the celebrated naturalist, 
 weighed 6^\ ounces ; that of Abercrombie,t phj'si- 
 cian and philosopher, 63 ounces, and that of Du- 
 puytren, :j; surgeon, 62|- ounces ; while the brain of 
 an idiot seldom exceeds thirty ounces in weight. 
 Occasionally men have possessed great intelligence, 
 and have been found after death to hava very small 
 brains. An example of this is the brain of a cele- 
 brated mineralogist (Haussmann), who is said to 
 have been above medium stature. Its weight was 
 only 43.24 ounces. In such cases, it is usually found 
 that the convolutions are very deep and very much 
 curved and turned about, so that there is a greater 
 amount of gray matter packed awa}^ than would 
 have been expected in so small a skull. 
 
 * Baron George Chretien Leopold Fr^eric Dagobert Cuvier, one 
 of the most eminent of modem scientific men (i 769-1 832), Professor 
 of Natural History in the College of France ; generally considered the 
 founder of the science of comparative anatomy, 
 
 •f John Abercrombie, a distinguished Scottish physician (1781-1844), 
 especially celebrated for his metaphysical writings. 
 
 X Baron Guillaume Dupuytren (1777-1835), during his lifetime con- 
 sidered the most eminent surgeon in France ; Professor of Surgery at 
 Paris. 
 
224 
 
 ORGANS OF CO-ORDINATION. 
 
 286. Effect of Injuries of the Brain. — It has also 
 been noticed, from the earliest times, that injuries 
 of the brain produce unconsciousness and various 
 other phenomena, which indicate that the organ 
 of the mind has been injured ; so that, by almost 
 all men, the fact that the brain is the seat of the 
 mind has been readily acknowledged. The deter- 
 mination of the particular portion of the brain 
 which is the organ of mental processes has only 
 been arrived at by long-continued study and ob- 
 servation. 
 
 287. Disease of the Human Cerebrum. — And 
 here, as in the case of the spinal cord, we find ex- 
 periments on human beings provided for us by 
 Nature. When the cerebrum of a human being is 
 diseased, we find that the mind is affected. This is 
 noticeably the case in the disease commonly known 
 as softening of the brain. The first symptoms in this 
 distressing malady are mental ones. The person 
 begins to lose his memory ; his friends probably 
 perceive it before he does himself ; and from this 
 first indication of intellectual feebleness the disease 
 goes on, often without any disturbance of the nu- 
 trition of the body, until the intelligence is com- 
 pletely abolished, and the person's life is a blank. 
 When the brain of such a person is examined after 
 death, the cerebrum is the part found diseased, 
 and we see that the gradual impairment and ex- 
 tinction of the mind, which we have been watching, 
 is the result of physical disease. 
 
 288. Recapitulation. — To recapitulate ; the evi- 
 dence that the cerebrum is the seat of the intelligence is 
 the following : First, we see that in the lower ani- 
 mals, as well as in man, the development of the 
 
THE BRAIN. 
 
 22C 
 
 mind is proportionate to the development of the 
 cerebrum in comparison with the rest of the body. 
 Second, that if the cerebrum be destroyed, the men- 
 tal faculties are the only ones lost. TJiird, when 
 the mind of a human being is impaired or lost, 
 we find a corresponding disease or injury of the 
 cerebrum."^ 
 
 289. Structure of the Cerebellum. — The gan- 
 glion next in size to the cerebrum, and one whose 
 functions are of great importance, is the ccrcbclluin, 
 or little brain (Figs. 57, 58). It is situated beneath 
 the back part of the cerebrum, occupying that por- 
 tion of the skull immediately behind the ears. Its 
 average weight is five and a quarter ounces, about 
 one ninth of the whole weight of the brain. It is 
 composed of gray and white matter, arranged in 
 much the same way as in the cerebrum, except- 
 ing that the convolutions are smaller and dip in 
 deeper, so that in the cerebellum the proportion 
 of gray matter is much greater than in the cere- 
 brum. This fact, of itself, would indicate its im- 
 portance. 
 
 290. Function of the Cerebellum. — The exact 
 function of this part of the brain has not yet been 
 
 * Also, when the cerebmm is seriously injured, the mental faculties 
 are generally impaired. There have been some cases of recovery after 
 vei'y severe injuries of the brain. In 1850 a young man in Vermont, a 
 farm-hand, was blasting rock, when a tamping-iron, three and a half 
 feet long and an inch and a quarter in diameter, was driven through 
 his head, entering the left cheek and coming out at the top of the head, 
 causing a great loss of brain-substance. He recovered completely from 
 the wound, but from a quiet, home-loving, honest lad, he developed 
 into a tricky, thieving fellow, of a roving disposition, lived in various 
 places in South America and the United States, was subject to epilep- 
 tic fit-i, and died in convulsions in California twelve years after the in- 
 jury. 
 
226 ORGANS OF CO-ORDINATION. 
 
 determined. There are difficulties in the way of 
 observations upon it, which are not found in simi- 
 lar observations upon the cerebrum. As the result 
 of many such observations, it has been suggested 
 that the cerebellum in some way controls and har- 
 monizes the voluntary muscular contractions, or, 
 as the physiologists express it, the cerebellum is 
 the seat of the co-ordinating power in voluntary 
 muscular movements. This idea was at one time 
 accepted, but it was found that in some cases of 
 injury to the cerebellum the power of co-ordinat- 
 ing movements was after a time regained. And 
 this was not the result of the healing of the injury, 
 for the lost portion of the cerebellum is found on 
 inspection not to have been renewed. 
 
 Diseases of this portion of the brain also give 
 contradictory data. Tumors and injuries of the 
 cerebellum often occasion difficulty in muscular co- 
 ordination, but, on the other hand, no disturbance 
 in the muscular movements has been detected in 
 some cases, where the disease of the cerebellum 
 has been very extensive. 
 
 Comparison of the relative development of the 
 cerebellum in different animals seems to favor the 
 theory proposed. 
 
 All things considered, however, scientific men 
 are agreed that the real function of the cerebellum is 
 not yet definitely known. 
 
 291. Other Ganglia of the Brain. — Besides the 
 cerebrum and cerebellum, there are various ganglia 
 of less size, all of which are situated on or near the 
 under surface of the brain. Observations upon 
 these are very difficult, and have been hitherto 
 unproductive of results. It is an undoubted fact, 
 
THE BRAIN. 
 
 227 
 
 however, that, unless destroyed by loss of blood, 
 life will continue after the cerebrum and cerebel- 
 lum have been removed, showing that these latter 
 organs are not essential to life. Of the remaining 
 ganglia, the tuber' cula qiiadrigcm' ina"^ are known to 
 be the centers by which vision is rendered possible. 
 The optic nerves take their origin in these small 
 ganglia, and the fact that they receive the impres- 
 sions which we call sight is proved in this way : If 
 the optic nerve be cut between the eye and the tu- 
 bercula quadrigemina, blindness results. The same 
 effect is produced by destruction of these bodies, 
 the optic nerves remaining uninjured. If, on the 
 other hand, the connections between these ganglia 
 and the cerebrum be severed, the ganglia and nerves 
 remaining intact, sight still remains, and vision is 
 also retained, if the cerebrum be removed and the 
 tubercula quadrigemina left untouched. These 
 things are sufficient to show that they are the cen- 
 ters of the sense of vision. 
 
 In some one or all of the remaining ganglia, 
 with the exception of the medulla oblongata, to be 
 hereafter described, the powers of sensation and 
 motion reside. This is known from the fact that, 
 after the removal of the cerebrum and cerebellum, 
 the animal is still capable of sensation and voluntary 
 motion ; but, if all the ganglia be removed, except- 
 ing the medulla, not only does consciousness dis- 
 appear, but all sensation and voluntary movements 
 cease, the special senses are abolished, and the only 
 manifestations of life are the continuance of the 
 
 * These small bodies arc situated above and in front of the cere- 
 bellum, between it and the cerebrum, and so are not shown in any of 
 the cuts. 
 
228 GRGAXS OF CO-ORDINATtON. 
 
 functions of respiration and circulation, and the re- 
 fiex movements of the parts connected with the 
 spinal cord. 
 
 292. The Medulla Oblongata. — The spinal cord 
 passes upward from the spinal canal into the skull. 
 Just after entering the cavity of the skull, it be- 
 comes somewhat enlarged, and this enlarged por- 
 tion is called the medulla oblongata (Figs. 57, 58). 
 It is about an inch and a quarter long, and three 
 quarters of an inch wide, and at its upper extremity 
 is merged in other parts of the brain. Imbedded 
 in this part of the cord is a small mass of gray 
 matter, which is more essential for the actual pres- 
 ervation of life than any other portion of the brain. 
 It has sometimes been called the " vital knot." If 
 this be destroyed, all manifestations of life in- 
 stantly cease. The cause of this is the intimate 
 relation which this part bears to the function of 
 respiration. 
 
 293. The Medulla Oblongata controls Respira- 
 tion. — The movements of respiration are to a cer- 
 tain extent under the control of the will, but, under 
 ordinary circumstances, we breathe unconsciously. 
 Inspiration and expiration take place regularly and 
 unceasingly, by night and by day, in our sleeping 
 as well as our waking hours. The nervous supply, 
 therefore, by which this function is controlled is, 
 so to speak, automatic. The requisite movements 
 are carried on by reflex action. How is this accom- 
 plished ? 
 
 As the processes of repair and waste go on, car- 
 bon dioxide and other waste matters accumulate in 
 the blood. When this venous blood, loaded with 
 impurities, arrives at the lungs, it imparts a peculiar 
 
THE BRAIN. 
 
 229 
 
 Stimulus to the large nerves, which are distributed 
 to these organs. They convey a sensation to the 
 medulla oblongata, and the corresponding motor 
 nerves convey the impulse from the gray matter of 
 the medulla oblongata, and cause a contraction of 
 the muscular walls of the chest. Inspiration then 
 takes place, the blood receives oxygen, the air is 
 expired again, and the chest- walls remain passive 
 until venous blood again accumulates in the lungs 
 in sufficient quantity to cause the requisite stimulus 
 in the medulla oblongata ; and so the process con- 
 tinues through a long life, independently of the will 
 of the individual. 
 
 294. Automatic Action of the Medulla Oblongata. 
 — Respiration, however, is in a measure under the 
 control of our will. We can hold our breath, if we 
 choose, for a short time ; but, with the cessation of 
 respiration, the blood becomes more and more 
 charged with impurities, until at length a peculiar 
 sensation begins to be felt, which we call " want of 
 breath," or ''shortness of breath." If we still resist 
 the desire to inspire, and hold the chest-walls im- 
 movable, this sensation increases until it induces 
 the most intense suffering, and the will is at length 
 unable to assert its power. The automatic action 
 of the medulla oblongata overrides our feeble oppo- 
 sition, and we breathe again, in spite of ourselves. 
 It is a lesser degree of this same sensation, with- 
 out a doubt, which acts as a constant stimulus to 
 the medulla oblongata, and keeps up the process 
 of respiration without our consciousness. Now, 
 when the portion of the medulla oblongata con- 
 taining this part, called the "vital knot," is de- 
 stroyed, respiration instantly ceases, and the cir- 
 16 
 
230 
 
 ORGANS OF CO-ORDINATION. 
 
 culation soon stops. This is the quickest way 
 known of killing animals, and is much used by 
 physiologists, when they wish to produce sudden 
 death, without injuring the blood-vessels or other 
 organs of the body on which they wish to experi- 
 ment.* 
 
 * In the great slaughtering establishments of the West, cattle are 
 killed by puncture of the medulla oblongata. Men stand upon a raised 
 platform, and, as the animals pass underneath, penetrate this organ 
 with a sharp spear, or with a bullet from a carbine. The matador, in 
 the Spanish bull-fights, also aims to strike this vital part, and his repu- 
 tation depends upon the success with which he does it. The Spaniards 
 execute criminals upon the same plan, by means of the garotte, which 
 consists of an iron collar surrounding the throat, with a steel pin pro- 
 jecting inward behind. A single turn of a large wheel forces this pin 
 into the medulla oblongata and causes instant death. 
 
CHAPTER V, 
 
 SPECIAL NERVES. — HYGIENE. 
 
 295. Nerves of the Head and Face. — In the 
 
 spinal .nerves, we have seen that the motor and 
 sensory fibers are mingled, so that each nerve con- 
 tains fibers of both kinds. In the nerves coming 
 from the brain this is commonl}^ not the case. As 
 
 a rule, some nerves are 
 entirely nerves of sensa- 
 tion, and others entirely 
 nerves of motion, and 
 the two functions are 
 not united in a single 
 trunk. These nerves 
 are arranged in pairs, 
 like the spinal nerves, 
 one going to one side 
 of the head or face and 
 the other to the other. 
 
 The two most im- 
 portant nerves of the 
 face are those called 
 the trigcnii)ial and the 
 facial. The trigeminal 
 nen^e (Fig. 60) emerges from the skull bv three 
 openings, being divided into three branches just 
 
 Fig. 60. — Diagram showinj^ the distri- 
 bution of the fifth nerve to the face. 
 
2^2 
 
 ORGANS OF CO-ORDINATION. 
 
 before it reaches these opening's. One branch sup- 
 plies the parts surrounding the eye, the forehead, 
 and the inside of the nose ; the second comes out 
 just below the eye, after sending branches to the 
 teeth of the upper jaw, and supplies the cheek, 
 the upper lip, and the outside of the nose ; while 
 the third comes out at a point near the front of the 
 lower jaw, and supplies the chin and lower lip, be- 
 sides having sent branches to the teeth and tongue, 
 before emerging from 
 the jawbone. These 
 nerves are the great 
 nerves of sensation of 
 the face, and are gener- 
 ally considered to be 
 the most exquisitely 
 sensitive nerves in the 
 whole body. They are 
 often the seat of neu- 
 ralgia, and give rise to 
 the most intense and 
 intolerable suffering. 
 
 The facial nerve 
 (Fig. 6i) is the motor 
 nerve of the face ; it 
 emerges from the skull 
 
 just below the ear, and, passing forward through 
 the parotid gland, is distributed to all the muscles 
 of the face. Paralysis of this nerve is far from un- 
 common, and produces a most singular and charac- 
 teristic effect upon the countenance. Exactly one 
 half of the face loses all expression, as much as if 
 dead, and the contraction of the muscles of the op- 
 posite side, not being in any way counteracted, pro- 
 
 FiG. 6i. — Diagram showing the distri- 
 bution of the facial nerve to the face. 
 
SPECIAL NERVES.— HYGIENE. 
 
 233 
 
 duces dreadful, though often ludicrous, distortion 
 of the features. This form of paralysis often occurs 
 among hackmen and others who are exposed to 
 stormy weather. If a strong wind, particularly 
 when accompanied by snow or sleet, be allowed to 
 beat upon the side of the face, there is great danger 
 of paralysis of the facial nerve. Such exposure of 
 the place where this nerve emerges from the skull 
 should be carefully avoided. 
 
 296. The Sciatic Nerve. — Each limb of the body 
 is supplied by large nerve-trunks, which, as a rule, 
 follow very nearly the course of the arteries. The 
 largest nerve of the leg, however, runs down be- 
 hind the limb, while the femoral artery runs down 
 the front of the thigh. This nerve is known as 
 the sciat'ic, and its branches extend to the foot. 
 It is this nerve which, when pressed upon in sitting, 
 gives rise to the sensation commonly described as 
 the " foot being asleep." 
 
 297. Importance of Reflex Action. — It is impor- 
 tant to call attention to the fact that reflex action has 
 a great deal to do with our health and safety, even 
 when the spinal cord and brain are in perfect con- 
 dition. People in general are hardly aware how 
 much they owe to this property of the nervous sys- 
 tem in time of danger. Familiar illustrations are 
 found in the rapid recovery of the bodily equilib- 
 rium, when the foot has slipped ; in the involun- 
 tary start and assumption of a position of defense, 
 when a horse and wagon suddenly run upon one in 
 the street ; in the start of the body at a sudden 
 noise ; in the instantaneous withdrawal of a portion 
 of the body when it is burned ; in the winking of 
 the eyelids, particularly at indications of danger ; 
 
234 ORGANS OF CO-ORDINATION. 
 
 and in hundreds of daily actions, which follow so 
 instantaneously upon the application of a stimulus, 
 that the thought, or mental appreciation of the 
 stimulus, does not come until after the reflex action 
 has already taken place.^ 
 
 When we consider the immense number of such 
 actions which take place every hour of the day, and 
 the stupendous work of nutrition, with its compli- 
 cated phenomena, all going on outside of our con- 
 trol, we see that in all probability the greater part 
 of the nervous force expended in the body goes to 
 produce involuntary movements, and to control and 
 preserve the health and integrity of our organism 
 in spite of ourselves. It is a suggestive thought 
 that, much as we appear to be our own masters, 
 independent as we seem to be of the outside world, 
 we are really ruled by the general vital forces 
 which equally rule all animals and even plants, 
 upon which we are all equally dependent, and over 
 which what we call *' we " have almost as little con- 
 trol in ourselves as in the lion that roams the des- 
 ert or in the grass that grows beneath our feet. 
 
 298. Education of the Nervous System. — The 
 hygiene of the nervous system has to do mainly with 
 the problem of education, and with the over- or un- 
 der-use of its parts. Education is a broad subject, 
 and can not be taken up here, but it is undoubtedly 
 
 * It is related of a distinguished chemist that a glass vessel once 
 exploded in his hands and was blown into a thousand pieces. His 
 hands were severely lacerated, and he at first feared that his sight was 
 destroyed ; but on examination it Avas found that he had closed his eye- 
 lids involuntarily at the instant of the explosion, and, although the lids 
 had been wounded in many places by the flying bits of glass, the eyes 
 were uninjured. The rapidity of such reflex action far surpasses that 
 of any voluntary movement. 
 
SPECIAL NERVES.— HYGIENE. 235 
 
 true that in the future much more attention will be 
 paid than in the past to the physical conditions 
 which underlie all development and training of the 
 mental powers. It is known that repetition of the 
 same process in any portion of the nervous system 
 renders it every time more and more easy. The 
 result of such repetition is what we call habit. The 
 more impressible and easily stimulated the different 
 parts of the nervous system are, therefore, the more 
 readily habits will be formed and the more firmly 
 they will become fixed. Now, the cells and fibers 
 of the nervous system of young and growing ani- 
 mals, like those of their muscular system, are espe- 
 cially soft and yielding, and, as they are constantly 
 growing, the changes in them are more frequent, 
 and they are much more easily influenced by any 
 stimulus than those of adults. Consequently chil- 
 dren and youths are especially liable to form habits, 
 and, in order to prevent the formation of bad ones, 
 they need the guidance and protection of older per- 
 sons. The experience of the young is not Avide 
 enough to inform them correctly of what is good 
 and what is bad, nor is it, in most cases, sufficient 
 to enable them to appreciate the wisdom of the 
 advice or commands of older persons. For these 
 reasons it is necessary, in the training of the 3'oung, 
 to require what often seems to them unreasonable, 
 and to forbid things with \yhat may seem to them 
 foolish pertinacitv. It is this readiness with which 
 habits are formed in the young, and the firmness 
 with which they become fixed, that render it so 
 dangerous for them to indulge in sensual gratifica- 
 tions, such as the drinking of liquids containing 
 alcohol, or to join in games which excite the selfish 
 
236 ORGANS OF CO-ORDINATION. 
 
 emotions in a high degree, such as lotteries and 
 gambling. 
 
 It is this ease of habit-forming in the young, too, 
 that renders childhood and youth the desirable time 
 for both mental and physical training. In fact, the 
 nervous system is, at this time, so impressionable that 
 the training will take place inevitably, whether it is 
 directed or not, and the success or failure of adult 
 life is generally determined by the conditions under 
 which the years below twenty have been passed. 
 
 299. Importance of exercising the Brain. — The 
 nervous system, like the muscular, must be suffi- 
 ciently exercised, in order to remain vigorous and 
 healthy. If the brain be allowed to remain indo- 
 lent, the faculties of memory and attention, the 
 power of concentrating the thoughts, will be con- 
 siderably weakened. It will be found that even 
 the inactivity of a few weeks' vacation will render 
 it a matter of some difficulty at first to keep the 
 brain at work at one's ordinary duties. Judicious 
 exercise also will strengthen special mental facul- 
 ties, just as proper training will develop muscular 
 power. The retentiveness of the memory may be 
 immensely increased, and the facility with which 
 the daily mental labor of the professional man is 
 performed, together with the increased efficiency 
 as age advances, shows the effect of directing the 
 nutritive processes constantly in the same direction. 
 In fact, this tendency is so strong that speciahsts, 
 all of whose energies for many years are directed 
 upon a particular subject, are very apt to become 
 narrow-minded or '' lop-sided," and unable to see 
 more than one side of any subject, and that some- 
 times the least important one. 
 
SPECIAL NERVES.— HYGIENE. 237 
 
 300. Danger of Over-Exercise. — On the other 
 hand, too much exercise is as injurious as too little. 
 All brain-work, as well as muscular work, involves 
 a waste of tissue. As we are thinking, our brains 
 are wearing out. And while this organ is actively 
 employed, the waste of tissue is greater than the 
 repair. When this excess of waste has reached such 
 a point that the proper working of the brain is inter- 
 fered with, we begin to feel incapable of further 
 study, the attention begins to waver, problems seem 
 difficult that at other times would be easy, and 
 perhaps the memory is at fault. Such a condition 
 demands imperative rest, and this rest is obtained 
 by sleep. 
 
 301. Sleep. — During sleep, the repair of all the 
 tissues goes on with great rapidity. As the body is 
 inactive, even the brain being in sound sleep en- 
 tirely unoccupied with thought, the waste of the 
 tissues is very small, almost the whole of it being 
 the result of the organic processes of circulation, 
 respiration, and digestion. In all of these organic 
 processes, which must be practicall}^ continuous, 
 rest is obtained at short intervals, the activity of 
 the organs concerned in them being intermittent, 
 and, although the intervals of rest are very short, 
 they are so numerous that they make up together 
 about half of the twenty-four hours. But the mus- 
 cular and nervous systems have no such frequent 
 intervals of rest during waking hours, the brain, in 
 particular, being constantly active, so that their rest 
 has to be taken continuously in the form of sleep. 
 
 During sleep, therefore, the repair of tissue runs 
 vastly ahead of the waste, and the exhausted parts 
 have their vigor and irritability rapidly restored. 
 
238 ORGANS OF CO-ORDINATION. 
 
 As the special senses and the sensitiveness of the 
 muscular and nervous systems had become dulled 
 and torpid because they were wasting away, so now, 
 as they are built up again, their sensitiveness re- 
 turns, and slight stimuli are sufficient to arouse them 
 into activity. We then wake up. Even the morn- 
 ing light may produce a sufficient effect upon the 
 eye, through the closed lids, to waken the sleeper, 
 and he rises refreshed for the work of another day. 
 The best time for sleep is night, because it is 
 dark and quiet ; the natural stimuli of the eyes and 
 ears are absent, and therefore rest can be obtained 
 with the least hkelihood of being broken. It is a 
 good rule for all persons to go to bed before mid- 
 night, and rise within ten minutes after waking in 
 the morning. The amount of sleep required by 
 each individual must be determined by himself 
 from experience. For most persons eight hours is 
 not too much, and many can do with less.* Chil- 
 
 * Marvelous stories are told of persons who can get along with very 
 little sleep. In most cases, if sleep is dispensed with at one time, it 
 must be made up at another, and some people possess the faculty of 
 falling asleep at odd moments, and making up, by what are sometimes 
 called " cat-naps," for the loss of regular sleep. Thus, Napoleon Bona- 
 parte is said to have been satisfied with four hours' sleep in the twenty- 
 four ; but this only refers to the time he spent in bed. He was in the 
 habit of sleeping on horseback during a march, and his traveling-coach 
 was made expressly so that the interior could be arranged as a bed. He 
 often fell asleep, too, for a few minutes at a time, in his study, with his 
 head resting on his arms on a desk in front of him. It maybe doubted 
 whether any person could live long with only four hours* sleep a day. 
 
 The Chinese sometimes punish criminals by confinement in a cage 
 where they can neither stand up nor sit or lie down. Attendants are 
 stationed to prevent the miserable men from falling asleep ; for even 
 under such conditions exhaustion brings on sleep. The unfortunate 
 men are pricked and pinched, and by various means of torture kept 
 awake until, as a rule, in eight or ten days, they die raving maniacs. 
 
SPECIAL NERVES.— HYGIENE. 
 
 ^39 
 
 dren need more, in proportion to their fewness of 
 years, and old people sometimes need less, because 
 of their comparative inactivity during their waking 
 hours. 
 
 302. Abuse of the Nervous System. — A word of 
 caution should be spoken about the various forms 
 of indulgence which affect the sympathetic S3^stem 
 of nerves. These include all those forms of sensual 
 gratification which are accompanied by a high de- 
 gree of physical pleasure, followed by a more or 
 less protracted period of depression. This depres- 
 sion, an instance of which is seen in the reaction 
 following intoxication, is the result of a great shock 
 and consequent great waste of tissue in the sympa- 
 thetic nervous system. Recovery from such shocks 
 is very slow. The sympathetic ganglia have to do 
 with the important function of nutrition. They lie 
 at the very foundation of life in our bodies. Their 
 ordinary duties are severe, and about all they can 
 attend to properly. Therefore, any great shock to 
 this part of the nervous system affects the very cen- 
 ters of life. This is the reason of the '' breaking 
 up," as it is called, which results from the various 
 forms of dissipation. This w^ord " dissipation " is 
 well used for such acts as are commonly included 
 under this head, as all kinds of debauchery, abuse 
 of the digestive organs, late hours, insufficient sleep 
 and relaxation, etc., dissipate nervous force with 
 frightful rapidity. 
 
 303. Effects of Alcohol upon the Nervous Sys- 
 tem. — Of all the means by which the nervous sys- 
 tem is abused alcohol probably stands first, by 
 reason of its extensive use and the very marked 
 deleterious effect it is likely to produce. Imme- 
 
240 ORGAXS OF CO-ORDINATION. 
 
 diately upon the introduction of an alcoholic drink 
 into the stomach a sensation of warmth is per- 
 ceived, followed by slight exhilaration. This is 
 probably due to the irritation of the nerves of the 
 stomach, even before the alcohol is absorbed. 
 When the alcohol has been taken into the blood 
 and reaches all parts of the body its peculiar effects 
 upon the nervous system become apparent. There 
 is at first a stage of excitement, when the brain 
 seems to be more active, ideas flow freely, there is 
 a disposition to laugh at trifles, and speech is less 
 circumspect than natural. Even in this stage of 
 intoxication, however, when the activity of the 
 brain seems to be increased, a close and sober ob- 
 server can see that a poisonous effect has been pro- 
 duced upon the nervous system. He can detect a 
 loss of control, a slight diminution of will-power, a 
 slight lack of coherence in trains of thought, and, 
 on the other hand, an increased tendency to laugh, 
 to declaim, to joke, to banter, which shows a dimi- 
 nution of intellectual power and an increased sensi- 
 tiveness of the emotional nature, the latter being, 
 however, not an actual increase, but a relative one, 
 the balance of the mind being disturbed and the 
 dominance of the intellect over the emotions being 
 partially suspended. The judgment is weakened, 
 control over the thoughts is lessened, and things 
 which when strictly sober the drinker conceals 
 often come to light in his conversation. In brief, 
 he is beginning to lose the mastery over himself. 
 
 304. Effect of Larger Doses of Alcohol. — If 
 more alcohol is taken this diminution of the regula- 
 tive force of the intellect becomes more marked. 
 The emotions have free sway. The person becomes 
 
SPECIAL NERVES.^HYGIENE. 
 
 241 
 
 maudlin, he laughs or cries with equal readiness, 
 becomes ludicrously affectionate or causelessly sus- 
 picious, he is obsequious in his politeness or obsti- 
 nate to rudeness, and his intellect is so far in abey- 
 ance that his judgment is lost, he can no longer 
 weigh consequences or reason upon occurrences, 
 and is the prey of every suggestion. The move- 
 ments of the voluntary muscles are no longer under 
 control. The currents of force sent along the 
 nerves are irregular and inco-ordinate. The tongue 
 seems thick and unmanageable, and speech is mum- 
 bling and indistinct; the lower limbs are moved 
 awkwardly and with a staggering gait ; the mus- 
 cles of the eyeballs no longer act in unison, but the 
 axes of the eyes are guided in different directions, 
 and double vision is the, result. All of the senses 
 are dulled, and the person often suffers injuries, of 
 which at the time he is unconscious. In this self- 
 inflicted degradation the drinker reduces himself 
 below the level of the lowest brute. But it should 
 be remembered that the first glass is the first step 
 toward such a state. 
 
 305. Effects of a Very Large Dose of Alcohol. 
 — If still more alcohol is taken, this condition rap- 
 idly merges into one of complete insensibility, and 
 the drunken man lies like a log, with muscles re- 
 laxed, with puffing or snoring respiration, with 
 glassy eyes, and, in extreme cases, abolition of all 
 functions, excepting those of vegetative life. Such 
 a condition may lapse into death, but more fre- 
 quently the alcohol is gradually eliminated from 
 the body by the lungs, kidneys, and skin, and re- 
 covery takes place. 
 
 Such a debauch is followed bv extreme nervous 
 
242 
 
 ORGANS OF CO-ORDINATION. 
 
 prostration, with great lassitude, dull headache, 
 giddiness, and sometimes dimness and yellowness 
 of vision on stooping and suddenly rising again, 
 accompanied by the disturbances of the digestive 
 organs already described. These symptoms are 
 surely not the effects of a food but of a rank poison. 
 
 306. How these Effects of Alcohol are Pro- 
 duced. — It is believed that alcohol enters into actual 
 combination with nervous tissue, and produces the 
 effects just described by preventing the normal nu- 
 tritive changes. This effect manifests itself as a 
 deadening of nervous sensibility, usually termed 
 narcosis. 
 
 307. Chronic Alcoholism. — When alcohol is 
 habitually taken in sufficient quantities, what is 
 called chronic alcoholism is the result. The symp- 
 toms of this condition are mainly due to the effect 
 of alcohol upon the nervous system. The first in- 
 dication is generally muscular tremor, especially 
 on rising in the morning. At first this tremor may 
 be stopped by a special effort of the will, but it 
 soon becomes uncontrollable. A glass of spirits, 
 however, will steady the muscles, and old topers 
 think they must always have this early in the morn- 
 ing. Soon the sleep begins to be disturbed. The 
 person, even if drowsy when he goes to bed, tosses 
 restlessly from side to side, unable to remain long 
 in one position, not from any pain or discomfort, 
 but simply from an indescribable feeling of dis- 
 quietude. If he obtains broken snatches of sleep, 
 he has frightful dreams. He rises unrefreshed, 
 and, even if he attends to his daily occupation, is 
 harassed by a constant feeling of dread and anxiety 
 for which he can assign no cause. He is troubled 
 
SPECIAL NERVES.— HYGIENE. 
 
 243 
 
 with noises in the ears and headache. The mind 
 becomes seriously impaired, the will is weak, and 
 great uncertainty of purpose is noticed by friends, 
 and perhaps by the sufferer himself. When the 
 chronic poisoning has reached this stage the drunk- 
 ard is on the verge of delirium tremens. 
 
 308. Delirium Tremens. — This frightful disease 
 may be the result of a single prolonged debauch, 
 but more commonly supervenes upon a long course 
 of drunkenness, or upon a greater indulgence than 
 common in persons who call themselves moderate 
 drinkers, i. e., persons who daily drink a considera- 
 ble amount of alcoholic liquor, but who never be- 
 come drunk. It may come on during a debauch 
 or after its close. The first symptom is absolute 
 sleeplessness. The sufferer is restless and troubled 
 with terrifying visions, usuall}" of disgusting or 
 horrible objects, black and crawling. He sees in- 
 sects, reptiles, or vermin on the floor or creeping 
 over the bed. These delusions persist in the day- 
 time, and he is constantly occupied with trying to 
 escape, pushing them away or resisting them with 
 violence. He often hears voices close to his ear, 
 mocking or threatening him. He is unable to take 
 food, and the muscular tremors previously spoken 
 of are incessant and distressing. In this pitiable 
 condition he may remain for several days, a sight 
 of horror, until sleep or death comes to his relief. 
 In the one case he generally wakes convalescent, 
 though greatly prostrated. In the other he often 
 dies in the midst of the most frightful visions, ex- 
 pending the feeble remnant of his strength fighting 
 his imaginary foes. 
 
 Chronic alcoholism sometimes produces attacks 
 
244 ORGANS OF CO-ORDINATION, 
 
 of insanity, in which the unhappy man tries to kill 
 himself or others. 
 
 309. Moral Deterioration due to Alcohol. — A 
 striking effect of alcoholic habits is the moral de- 
 terioration they produce. The drinker at first loses 
 the finer and nobler traits of character, and gradu- 
 ally, as the habit increases, becomes untruthful, dis- 
 honest, and lazy ; he loses his self-respect, and be- 
 comes so shameless and regardless of the laws of 
 society and the state that he often has to be cast off 
 and disowned by his dearest friends for their own 
 protection. Many paupers owe their degradation 
 to this alone. It should be borne in mind that it is 
 the nature of alcohol, though taken only in small 
 quantities, to create the appetite that leads to these 
 results. 
 
 . 310. Effects of Alcohol on Nervous Tissue. — 
 It has been found that the nervous system of 
 drunkards undergoes marked changes, which can 
 be detected by the microscope. They are of a 
 similar nature to those occurring in other parts 
 of the body, viz., an increase of connective tissue 
 and of fatty matters. The nerve cells and fibers 
 become shrunken and wasted ; there may be soften- 
 ing of the brain, or small haemorrhages here and 
 there upon its surface ; the enveloping membranes 
 of the brain are thickened, and the whole amount 
 of the brain-substance is lessened, the cavity of the 
 skull being kept full by the transudation of serum 
 from the blood. 
 
 311. Hereditary Effects of Alcohol. — The de- 
 generative changes produced by alcohol upon the 
 nervous system are not confined to the drinker 
 alone, but may reappear in his children and grand- 
 
SPECIAL NERVES.— HYGIENE. 245 
 
 children. These may manifest themselves in vari- 
 ous ways, either by the recurrence of the alcoholic 
 appetite in the child, by tendencies to immorality, 
 by nervous disorders like epilepsy, idiocy, and in- 
 sanity, or by a weak condition of the nervous sys- 
 tem in which the more serious disorders may result 
 from slight causes. Instances have been known 
 where all the children of a family born after the 
 father began to drink were either v/eak-minded or 
 had some serious nervous disorder. 
 
 312. Other Poisonous Substances in Alcoholic 
 Drinks. — The bad effects which have been de- 
 scribed as due to the use of beverages containing 
 alcohol are increased by the fusel-oil and ethers 
 contained in them. All liquors distilled from grain, 
 potatoes, or other starchy substances, contain fusel- 
 oil (or, as it is also called, amylic alcohol). This is 
 especially injurious, and delirium tremens and other 
 serious derangements of the nervous system occur 
 much more frequentlv in persons who drink liquors 
 containing it — such as new whisky, and gins, brand- 
 ies, or wines, which have been manufactured out of 
 potato-spirit, or to which it has been added. The 
 oil of worm-wood, which is found in absinthe, is 
 exceedingly dangerous, and rapidly produces in 
 those who use it a peculiar form of insanity with 
 muscular tremors, giddiness, and epileptic convul- 
 sions. These oils also develop the various degen- 
 erations of organs much more rapidly than ethylic 
 or common alcohol. 
 
 313. Effect of Tobacco on the Nervous System. 
 — The great and general depression produced by 
 tobacco, when used for the first time, is mainly due 
 to its effect upon the nervous system. The feeble- 
 
 17 
 
246 ORGANS OF CO-ORDINATION. 
 
 ness of the heart's action, the pallor of the surface, 
 the distress at the pit of the stomach, are all due to 
 a poisoning of great nerve-centers by the nicotine. 
 But, as with alcohol and opium, the nervous sys- 
 tem gradually accommodates itself, after a fashion, 
 to repeated attacks of this poison, so that its de- 
 pressing effect is only felt in a slight degree when 
 the weed is used in moderate amount. It then dulls 
 the sensibilities, so that the man who is tired and 
 needs rest does not realize his weariness. It is 
 probable that this effect is produced in the same 
 way and for the same reason as the nausea and 
 giddiness that mark the first experience with tobac- 
 co. It is due to a diminution of the blood-supply 
 in the brain. The brain is pallid, if we could see 
 it, like the skin. Now, when the mind is worried 
 or irritated, the brain is congested, the blood-ves- 
 sels are overfilled, and the tissue-changes are more 
 rapid than is healthy. The proper and natural re- 
 lief in such cases comes from rest and the with- 
 drawal of all cause of irritation, when, in a healthy 
 person. Nature will restore the circulation to its 
 normal condition. But man knows so much better 
 how to manage himself that he introduces a poison 
 into his body to depress the heart's action and ren- 
 der it too weak to keep the small blood-vessels well 
 filled. As the blood-supply is lessened the changes 
 in the brain-cells are less rapid, and the person 
 calls himself soothed, when he is, in fact, poisoned. 
 It is not known that tobacco causes permanent 
 injury to the structure of the brain, as alcohol does, 
 but it will sometimes give rise to wakefulness, in- 
 terfering greatly with rest at night, making the 
 smoker nervous and irritable, with tremulous mus- 
 
SPECIAL NERVES.— HYGIENE. 
 
 247 
 
 cles, thus bringing about apparently the very con- 
 dition it is intended to control. This form of 
 nervous irritability, however, is due to a failure of 
 proper nutrition of the brain, by reason of a lack 
 in blood-supply, while the other form is due to 
 oversensitiveness of the nerve-cells, caused by an 
 excess of blood in the brain. When tobacco is 
 abandoned, however, the bad symptoms disappear 
 with signal rapiditv. 
 
 314. General Effect of Opium on the Nervous 
 System. — Opium produces its greatest effect upon 
 the nervous system. Unlike alcohol, its use is not 
 followed bv extensive des^eneration of orsfans and 
 tissues, so far as can be discerned by examination 
 after death. It must, however, produce a lasting 
 alteration of the nerve-cells, or it would not give 
 rise to the great ps\'chical changes which invaria- 
 bly attend its habitual use. 
 
 315. Effect of a Small Dose of Opium. — A small 
 dose of opium — one grain, for instance — is followed 
 in a short time by moderate excitement, the pulse 
 growing stronger and eight or ten beats quicker to 
 the minute. It falls again, however, in half or three 
 quarters of an hour. The mouth and throat are 
 dry, and perspiration often breaks out. The brain 
 and nervous system soon feel the narcotic effect of 
 the drug, and in forty or fiftv minutes the person 
 grows sleepy, and, if it be night, will probably sleep 
 all night, though in the daytime he will wake, per- 
 haps in two or three hours. After waking there is 
 some depression and disturbance of the digestive 
 
 organs. 
 
 316. Effect of a Larger Dose of Opium. — If the 
 
 dose is larger — two or three grains — it is followed 
 
248 ORGANS OF CO-ORDINATION. 
 
 by great excitement, with noises in the ears, and 
 the ideas are confused and extravagant. The head 
 soon feels heavy and dull, the senses are blunted, 
 and deep sleep follows, attended by dreams of a 
 disagreeable nature. The reaction after narcotism 
 has passed off is proportionately greater. 
 
 317. Effect of a Dangerously Large Dose. — 
 After a large dose, one which involves danger of 
 death, the stage of excitement is very brief, there 
 is a sense of giddiness and oppression, soon fol- 
 lowed by profound sleep. The pulse, which at first 
 was full and strong, becomes small and feeble. The 
 pupils are strongly contracted, often like a pin- 
 point in size. The face is pale, the respiration slow 
 and labored, and the muscles are in a state of com- 
 plete relaxation. Such a condition soon passes into 
 death, sometimes preceded by convulsions. 
 
 318. The Opium - Habit. — The sensations pro- 
 duced by a small dose of opium in some persons 
 tempt them strongly to take it again. It is at first 
 a luxury, a mere matter of sensual gratification, 
 but, before the individual is aware of the fact, he is 
 the slave of the opium-habit. He finds that the 
 agreeable feelings induced by the opium he has 
 been taking begin to be replaced by others of a 
 horrible or disgusting character. After the effects 
 of a dose have passed away he is gloomy, depressed, 
 and wretched, and feels a ravenous gnawing of the 
 stomach, which can only be appeased by more 
 opium. Then he begins to struggle against his 
 chains, and the more hopeless he finds the struggle 
 the deeper becomes his despair and gloom. The 
 drug no longer affords him pleasure ; it merely re- 
 lieves his suffering. He takes it now not for en- 
 
SPECIAL NERVES.— HYGIENE. 249 
 
 joyment, but to escape unspeakable misery, and to 
 his horror finds that he must constantly increase 
 the dose. 
 
 319. Mental, Moral, and Physical Deteriora- 
 tion produced by Opium. — The moral deterioration 
 resulting from the habitual use of opium is fully 
 equal to that caused by alcohol. The opium-eater 
 becomes untruthful, slothful, unambitious, and care- 
 less, wrapped up in the gratification of his unnatu- 
 ral appetite, and regardless of the means he adopts 
 to satisfy it. 
 
 The memory fails, the temper becomes fanciful 
 and capricious, the will is broken, energy disap- 
 pears, giddiness, neuralgias, and sleeplessness su- 
 pervene, and partial paralysis of the muscles of the 
 back and limbs is common, so that the sufferer 
 shuffles along bent, shriveled, and weak, like a de- 
 crepit old man. 
 
 Death often results from marasmus, or a gradual 
 wasting away, due to the general failure of nutri- 
 tion, the effect of the drug upon the digestive appa- 
 ratus. 
 
 320. Effects of the Chloroform-Habit. — Chloro- 
 form is eliminated so rapidly by the lungs that the 
 period of excitement is very short, and its habitual 
 use as an intoxicant is for its stupefying effect. For 
 some persons the gradual lapse into insensibility is 
 attended by such pleasurable sensations that they 
 acquire the habit of inhaling chloroform to produce 
 it. Its long-continued use is followed bv sleepless- 
 ness, tremulousness of the muscles, and marked 
 inability to fix the attention upon any subject. If 
 its use is persisted in after these preliminarv symp- 
 toms have appeared, it retards the tissue changes 
 
250 ORGANS OF CO-ORDINATION. 
 
 in the blood, and produces marasmus and a melan- 
 cholic form of insanity. The drug is a very dan- 
 gerous one, tending to produce sudden death by 
 paralyzing the nervous ganglia of the heart. 
 
 321. Effects of the Chloral-Habit. — Chloral, in 
 moderate doses, fifteen or twenty grains, brings on 
 a sleep very much like the natural sleep. The per- 
 son can be easily aroused from it, and it is followed 
 after waking by no depression or nausea. It thus 
 becomes a valuable drug in the hands of physicians. 
 If it is habitually used, however, it is followed by 
 various disagreeable effects. The blood becomes 
 thin and watery, and eruptions or blotches occur 
 on the skin ; there is some irritation of the eyes and 
 throat, shortness of breath, and pains in the limbs. 
 There may be even partial paralysis of the lower 
 limbs, and there is great deterioration of the mental 
 and moral nature. Death may result from gradual 
 failure of the heart, or more commonly from the 
 effect of a poisonous dose inadvertently taken. 
 
 322. Cause of the Craving for Narcotics. — The 
 unnatural craving felt by the drinker is shared by 
 all who become slaves to a narcotic. It is probably 
 due to the fact that these poisons enter into actual 
 contact with the nerve substance. This has been 
 shown to be true of alcohol, and although the 
 changes produced by the other narcotics are not 
 known, the similarity of their effect upon the nerv- 
 ous system suggests that they may act in the same 
 way. A combination between the alcohol and the 
 nerve-matter of cells and fibers renders the compo- 
 sition of the nervous substance different from nor- 
 mal, but the body accustoms itself, after a while, to 
 the new order of things. When the alcohol has 
 
SPECIAL NERVES.— HYGIENE. 251 
 
 disappeared from the tissues of the body the nerve- 
 cells are left in a state of disorganization. Disor- 
 ganization of cell-structure means the beginning of 
 death, and the whole body sends up a cry for relief. 
 And the relief must be immediate and easily at- 
 tained in order to abate suffering. If the drunkard 
 whose nervous system has been brought to this 
 state, in which the cells are in a continual state of 
 unrest unless combined with alcohol, can be pre- 
 vented from obtaining it for a considerable time, 
 the cells will gradually become able to appropriate 
 food material they need from the blood, and, after 
 a time, resume their normal condition. Then the 
 craving ceases. 
 
 This craving for narcotics is the most terrible 
 fact connected with their use. It constitutes a slav- 
 ery of the most dreadful kind. It is more hopeless 
 in some cases than in others. The chains of the al- 
 cohol slavery may be broken. The use of tobacco 
 may perhaps be given up more easily. But the 
 slavery to opium is pitifully lasting. Few ever es- 
 cape from its toils. It is even doubtful if any do, 
 when the net is once fairly cast about them. 
 
PART V. 
 
 ORGANS OF PROTECTION. 
 
 CHAPTER I. 
 
 THE SKIN. 
 
 323c The Skin. — The skin, with its appendages, 
 is a complex organ, and has many functions. It 
 serves for protection, contains nerves of sensation, 
 secretes, absorbs, and excretes, and its functions are 
 so necessary to life that, if in any way it be rendered 
 unable to perform its duty in the organism, death is 
 the result. 
 
 324. Structure of the Skin. — The skin is com- 
 posed essentially of two layers, one called the cuticle 
 or epidermis, and the other the cutis or derma (Fig. 
 62).^ The former is the outside layer, and the lat- 
 ter the inside. The epidermis consists of small, flat- 
 tened, dry scales, and receives the brunt of injuries 
 and abrasions. The thickness of this layer is shown 
 in a blister, the epidermis being there separated 
 from the layer beneath by the fluid which fills the 
 vesicle. f The inner layer, or derma, constitutes 
 
 * Cutis is the Latin for skin, and cuticle means little skin ; derma 
 is the Greek for skin, and epidermis means the outer layer of the skin, 
 or, literally, " upon the skin" 
 
 \ Vesicle is from the Latin, and means a bladder, which a blister 
 somewhat resembles. 
 
THE SKIN. 
 
 253 
 
 what is sometimes called the true skin. This layer 
 alone contains nerves, blood-vessels, hair-bulbs, and 
 
 Epidermis. 
 
 PigmeiU-cells. 
 Papillae. 
 
 1 
 I 
 
 J- Derma. 
 
 .-% J 
 ^/ j^S^^ '(^C#)' z'^-'-*' Sweat-glands. 
 
 Fatty tissue. 
 
 Fig. 62. — Diagram representing- a vertical section of the skin. Attached to 
 the hair are two sebaceous glands. 
 
 the Other appendages of the skin. It is made up of 
 strong interlacing fibers of connective tissue, which 
 form a firm, close covering for the delicate tissues 
 beneath. This layer varies in thickness in different 
 parts of the body, from one fiftieth to about one sixth 
 of an inch. For instance, the skin of the eyelid is 
 very thin, while that of the small of the back is the 
 thickest in the body. 
 
 325. The Derma. — The under surface of the 
 derma is merged in the loose connective tissue 
 which lies between the skin and the flesh. It is in 
 this loose tissue that fat accumulates, and, in conse- 
 quence of its peculiarlv loose and flexible structure, 
 the skin can be moved easily in any direction, slip- 
 ping or gliding, with no pain and no disagreeable 
 sensation, over the tissues immediately beneath it. 
 The upper surface of the derma is covered with 
 
254 ORGANS OF PROTECTION. 
 
 little elevations, called papiVlce, which, on an aver- 
 age, are about y^-g- of an inch in length, and ^^ of 
 an inch broad at the bottom. They are somewhat 
 conical in shape, and in their interior are found the 
 ends of sensitive nerves. In some parts of the 
 body they are scattered irregularly on the surface 
 of the derma, while in other regions they are ar- 
 ranged in rows, and produce the appearance of 
 small parallel ridges on the surface of the body. 
 T"his latter arrangement is most distinctly to be 
 seen on the palm of the hand and fingers, and in 
 these parts also the sense of touch is most highly 
 developed. 
 
 326. The Epidermis. — The epidermis lies in im- 
 mediate contact with the derma, its under surface 
 being accurately molded to fit the papillae. But, in 
 the under portion of it, the portion into Avhich the 
 papillae project, the scales, instead of being flat and 
 hard, are rounded and soft, and contain a certain 
 amount of coloring -matter, in the form of small, 
 dark granules. As this part of the epidermis 
 varies in color and thickness, so the complexion 
 of the person varies.* In the negro, these pig- 
 ment-cells, as they are called, are very dark and 
 numerous, and there are all gradations in the 
 amount of the coloring-matter in different persons, 
 from the coal-black African to the albino, in whom 
 there is no color at all, except the red tinge given 
 by the blood. 
 
 * This layer of pigment-cells seems to protect the parts beneath 
 from the action of the sun. The natives of all tropical countries are 
 dark, and exposure to the sun's rays, even in our climate, tans the skin 
 to a darker hue. Sometimes this effect of the sun is more noticeable 
 in particular spots, producing what are known as freckles. 
 
THE SKIN. 255 
 
 327. The Nails. — Near the ends of the fingers 
 
 and toes the skin takes on a pecuHar appearance. 
 The epidermis is very closely applied to the derma, 
 with no colored cells between them, and the scales 
 of which it is composed are singularly dry and 
 hard, and semi-transparent. These peculiar growths 
 are called the nails. The part of the finger from 
 which they grow is called the root of the nail, and 
 the nail grows both in length and thickness. It is 
 formed by the continual pushing forward of new 
 cells, both from the root and from the under sur- 
 face. The growth from the root makes it grow in 
 length, while the addition of cells on the under 
 surface renders it thicker at the forward end than 
 it is near the root. The nails were probably once 
 a means of defense and offense, when men were in a 
 low, barbarian state ; but, at the present day, their 
 chief value appears to be for ornament, and as a 
 support for the pulp of the finger.* 
 
 328. The Hair. — The hairs are peculiar growths 
 of the skin. At certain points the surface of the 
 skin seems to dip inward, forming a deep pit or 
 pocket, at the bottom of which is a little projection 
 or papilla. From this papilla the hair grows, and, 
 emerging from the pocket, attains in some parts of 
 the body a considerable length. f The bod}^ or 
 shaft, of a hair consists of cells, flattened and hard, 
 but through its center, from one end to the other, 
 
 * The nails are of special use in the way last mentioned. The 
 finger-tips are extremely sensitive, and the hard, stiff nail serves as a 
 backing against which it can be pressed by the objects it touches. In 
 this way the nails increase materially the delicacy of touch. 
 
 f Instances have been known of women with hair six or seven feet 
 in length, and of men whose beards measured nearly as much. Such 
 cases, however, are very rare. 
 
256 ORGANS OF PROTECTION. 
 
 runs a hollow canal, filled with pig-ment-cells. These 
 cells, according to the amount of the coloring-mat- 
 ter in them, give the hair the appearance known as 
 black, brown, gray, auburn, etc. Almost the whole 
 surface of the body is covered with hair, excepting 
 the palms of the hands and the soles of the feet, but 
 most of it is of a soft, downy variety, which is not 
 visible without close observation. 
 
 329. The Sebaceous Glands. — There are certain 
 small glands, situated in the substance of the derma, 
 which are called the sebaceous ^ glands, or sometimes 
 the oil-glands. They are composed of minute sacs 
 lined with epithelial cells, which constantly secrete 
 and pour out of their mouths a whitish, tallow-like, 
 fatty substance. Most of them empty into the hair- 
 pits or follicles,t as they are called, and thence their 
 secretion runs along the hair, and out on the sur- 
 face of the body. They aid in keeping the hair and 
 skin soft and flexible. Sometimes the opening, by 
 which the secretion of the gland is discharged, 
 becomes obstructed, and the gland still goes on 
 secreting. In such a case, a swelling makes its ap- 
 pearance at the seat of the trouble, and the irrita- 
 tion of the retained secretion causes an inflammation 
 to set in, which continues until the contents of the 
 inflamed sac are discharged, or let out by the prick 
 of a needle. This is the cause of the unsightly lit- 
 tle pimples or boils which occasionally come on the 
 end of the nose, and give rise to great annoyance. J 
 
 * Seba'ceous, from the Latin sebum, meaning fat, or tallow. 
 
 f FoVlide, from the Latin word follicuhis, meaning a little sack or 
 J)0uch. 
 
 X There are many of these sebaceous glands about the end of the 
 nose, and the little openings, by which their secretion reaches the sur- 
 face, often become obstructed by dirt, so that the secretion accumulates 
 
THE SKIN, 
 
 257 
 
 330. The Sweat-Glands. — There are still other 
 glands in the skin which have a very important 
 part to play in the maintenance of life itself. These 
 are the sweat-glands^ or perspiratory glands. They 
 are situated either in the lowest layer of the derma 
 or in the loose connective tissue just beneath it. 
 The mass of one of these glands is convoluted — 
 i. e., it is made up of a long tube, rolled about and 
 twisted into a ball. This tube is lined with epithe- 
 lial cells, like the interior of all glands, and, after 
 leaving the convoluted portion, it passes in quite 
 a direct course through the derma, and then in 
 a spiral course, like the thread of a corkscrew, 
 through the epidermis, on the surface of which it 
 opens. If one of these little glands be unrolled, 
 and its tube stretched out, it is found to be about 
 yi^- of an inch in length, while its diameter is about 
 T^ of an inch. Notwithstanding their minute size, 
 however, there are so man}' of them that their se- 
 creting surface is enormous. They are least nu- 
 merous on the neck and back, where there are 417 
 to the square inch, and they are found in the great- 
 est numbers on the palm of the hand, where there 
 are no less than 2,700 of them to the square inch. 
 The total number is said not to be less than 2.300,- 
 000, and by a simple calculation it will be found 
 that the total length of these minute tubes, if care- 
 fully unrolled and placed end to end, would be 
 about two miles and a half ! 
 
 in the interior. When this is squeezed out, it looks like a small, white 
 worm, the dirt at the outer end resembling the head. Hence the term 
 "black-heads." To be sure, there are sometimes little worms found 
 imbedded in this secretion, but they are only to be seen with the mi- 
 croscope. 
 
CHAPTER II. 
 
 FUNCTIONS OF THE SKIN. — HYGIENE. 
 
 331. Effects of Pressure on the Skin. — It is evi- 
 dent, without demonstration, that the skin protects 
 the parts beneath it. In the performance of this 
 function, it sometimes resents too great pressure, or 
 unequal pressure, from outside. In such cases the 
 skin becomes thicker in spots where the pressure 
 occurs. If the epidermis only is affected in such 
 cases, and there is merely an increased production 
 of epidermal cells from beneath, the skin becomes, 
 as we say, callous. If, however, the derma be affect- 
 ed, the papillae become enlarged and project above 
 the surface, warts are produced, and, where both 
 forms of growth take place, we have corns. Press- 
 ure is undoubtedly not the only cause of the devel- 
 opment of these unpleasant diseases, but it is one 
 cause. But the origin of warts, in particular, is 
 generally obscure. 
 
 332. Animal Heat. — The skin also has an impor- 
 tant function to perform in maintaining a uniform 
 temperature in the body. Every one knows that a 
 living body is warm. Why is it so? There has 
 been much discussion on this point, and many theo- 
 ries proposed regarding it. When oxygen was first 
 
FUNCTIONS OF THE SKIN.— HYGIENE. 259 
 
 discovered, Lavoisier* supposed that the process of 
 respiration was a process of combustion ; that the 
 oxygen which entered the lungs in the air united 
 directly with the carbon in the venous blood, and 
 produced carbon dioxide. In ordinary flame, this 
 is the chemical change which accompanies combus- 
 tion. The ox3'gen of the air unites with the carbon 
 of the tallow or oil and produces carbon dioxide, 
 the hydrogen of the oil also uniting with oxygen to 
 produce water. Thus we get, as a result of com- 
 bustion, a disappearance of oxygen and a produc- 
 tion of carbon dioxide and water. Now, in the air 
 which passes in and out of the lungs, we find the 
 same thing. Oxygen passes in, and carbon di- 
 oxide and water, in the form of vapor, come out. 
 What more natural, then, than to conclude that 
 respiration was combustion, and the lungs a sort of 
 stove by which the heat of the body was kept up ? 
 
 It was soon found, however, that the lungs were 
 no warmer than the rest of the bodv, and particu- 
 larly that the blood contained carbon dioxide be- 
 fore it reached the lungs, and took away free oxygen 
 from them. These facts showed conclusively that 
 the change did not take place in those organs. 
 
 The great chemist, Liebig,t then changed the the- 
 
 * Antoine Laurent Lavoisier, a celebrated French chemist (1743- 
 1794). He first discovered the composition of water, and invented a 
 chemical nomenclature which lasted for more than fifty years. He was 
 guillotined during the French Revolution, because, twenty years before, 
 he had been a tax-gatherer under the monarchy. 
 
 f Baron Justus von Liebig, a renowned German chemist (1S03- 
 1873), Professor of Chemistry at Munich, He was the greatest chem- 
 ist of his time, made many practical applications of chemistry in agricul- 
 ture and the arts, and was one of the founders of the science of organic 
 chemistry. 
 
26o ORGANS OF PROTECTION. 
 
 or J, by supposing that the. combustion took place, 
 not in the lungs, but in the tissues generally through- 
 out the body, and this theory was for a long time ac- 
 cepted. It is now giving way, however, as it has 
 been found that many other chemical processes, be- 
 sides the union of carbon and oxygen, give forth 
 heat, and that the amount of oxygen inhaled with 
 the breath hardly ever corresponds with the amount 
 contained in the carbon dioxide expired. It is now 
 considered that the heat of the body is the result, not 
 of one class of chemical phenomena, but of all the 
 molecular changes and combinations which are con° 
 stantly taking place in all parts of the body. 
 
 333. Normal Temperature of the Human Body. 
 — The temperature natural to any animal is found 
 to be such that, if the blood be made very much 
 cooler or very much warmer, it is fatal to life. The 
 proper temperature of the interior of the human 
 body is about 100° Fahr. On the surface, of course, 
 some parts are cooler than others, according to the 
 degree of exposure to which they have been sub= 
 jected. Physicians usually take the temperature of 
 patients by placing the bulb of a thermometer in 
 the armpit, and the instrument in this spot gener- 
 ally registers about 98!-° Fahr. The normal tem- 
 perature often varies i° or 1° from this standard, ac- 
 cording to the time of day or night, and according 
 to the sleeping or waking condition of the person. 
 
 334. Great Variations in External Temperature. 
 — Now, if the blood be cooled much below this 
 point, say down to 80°, death takes place ; equally 
 so if it be heated to a temperature of ii3°o In the 
 former case, the person is said to have been frozen, 
 for the temperature can not be reduced to this point 
 
FUNCTIOXS OF THE SKIX.— HYGIENE. 261 
 
 unless by exposure to a very frigid atmosphere; 
 and, in the latter case, he is said to die of sunstroke, 
 because such a temperature is rarely induced, ex- 
 cepting in extremely hot weather. 
 
 But persons are often exposed to a temperature 
 of 10° or 20° below zero, and of from 100° to 130° 
 above zero. The latter figures, perhaps, require 
 a word of explanation. We are apt to think of the 
 temperature to which we are exposed in a hot sum- 
 mer's day as the same which we find registered by 
 a thermometer hanging in a sheltered spot. This 
 is an incorrect way to estimate it. Many of us, 
 perhaps most of us, spend some time every day in 
 the direct rays of the sun, and it is no uncommon 
 thing for a thermometer placed in the same situa- 
 tion to register 130°. How, then, are we enabled 
 to resist such extremes of cold and heat, and main- 
 tain our bodily temperature almost unchanged ? 
 
 335. Effect of Cold on the Body. — When the 
 body IS exposed to a low temperature, and the sur- 
 face is being continually cooled bv radiation, the 
 first effect, as the cold reaches the tissues just un- 
 der the skin, appears to be a stimulating one ; the 
 processes of nutrition, of cell destruction and for- 
 mation, take place with greater rapidity, and there- 
 fore more food is required to supply the waste. 
 We all know that in cold weather our appetites are 
 more keen, and, if we digest more, we must waste 
 more, or else accumulate material in our bodies. 
 This latter phenomenon does take place to some 
 extent, and most persons gain flesh during cold 
 weather.* Now, these changes in nutrition, with 
 
 * Cold weather produces a craving for fatty foods. The Esquimaux 
 eat enormous quantities of blubber. Dr. Hayes, the Arctic explorer, 
 18 
 
262 ORGANS OF PROTECTION, 
 
 increased activity, give rise to an increase of tem- 
 perature, and, up to a certain point of exposure, this 
 increase of heat is sufficient to balance the increased 
 radiation. When the radiation becomes excessive, 
 and the greatest activity of the bodily functions is 
 insufficient to produce enough heat to compensate 
 for it, the blood begins to grow cool, and the symp- 
 toms of drowsiness and stupor come on, which are 
 the precursors of death. 
 
 ZZ^' Effect of Heat on the Body. — On the other 
 hand, when the temperature is high, the tendency 
 to the accumulation of too much heat in the body 
 is kept down partly by a diminution of activity in 
 the nutritive processes, and partly by the action of 
 the perspiratory glands. In hot weather, the nu- 
 tritive processes go on much more slowly than in 
 cold, we eat much less food, most of us lose flesh, 
 and the production of animal heat in the interior 
 of the body is thus very much reduced. But this 
 reduction is not suf^ficient to guard us against the 
 harmful effects of a very high temperature. If cold 
 becomes too great to be resisted by the ordinary 
 forces at work within the body, we put on addi- 
 tional clothing, build ourselves fires, shelter our- 
 selves in houses, etc., and thus keep warm. But in 
 hot weather, if we had no perspiratory glands, we 
 should be badly off indeed. 
 
 337. How the Temperature of the Body is regu- 
 lated. — -The way in which these glands regulate the 
 temperature of our bodies is by covering the sur- 
 
 states that his men often drank clear oil with great relish, and the 
 Laplanders are said to be fond of tallow-candles. Even in our own 
 climate, fried articles of food, which contain a good deal of fat, are 
 palatal)le in winter, but very distasteful in warm weather. 
 
FUNCTIONS OF THE SKIN— HYGIENE. 263 
 
 face of the skin with a watery fluid, whose evapora- 
 tion continually abstracts heat. Evaporation con- 
 sists in the change of a liquid into vapor. The 
 evaporation of any liquid causes a diminution of 
 temperature in whatever lies in contact with it. 
 Liquids which evaporate very rapidly, Uke ether, 
 produce a very striking sensation of cold, and may 
 even be used, in the form of spray, to freeze a por- 
 tion of the body. Now when the surface of the 
 body is heated, the vaso-motor nerves are some- 
 what paralyzed, and an unusual flow of blood takes 
 place to the capillaries of the skin. A great flew 
 of blood to a gland causes an increased secretion, 
 and accordingly the perspiratory glands immedi- 
 ately begin to pour forth their peculiar secretion. 
 The perspiration is composed of water and salts, 
 containing about 99I- per cent of water. This water 
 evaporates rapidly, and abstracts so much heat that 
 the temperature of the body is kept at its normal 
 standard. 
 
 338. Effect of Alcohol on the Temperature of 
 the Body. — Experiments to determine the effect of 
 alcohol upon the bodily temperature have given 
 very contradictory results. In healthy persons, un- 
 accustomed to its use, full doses of alcohol produce 
 a slight fall of temperature, while if the quantity is 
 large enough to intoxicate there may be a fall of 
 3° or 4° Fahr., lasting for several hours. In persons 
 who are in the habit of drinking the temperature 
 will often not be affected even by quite large doses. 
 
 It was formerly believed that the use of alco- 
 holic liquors enabled men to endure extremes 
 of heat and cold better than they could without 
 such assistance ; but the testimony of travelers, ex- 
 
264 ORGANS OF PROTECTION. 
 
 plorers, and army officers is now overwhelmingly 
 against any such proposition. The action of alco- 
 hol in paralyzing temporarily the vaso-motor nerves 
 results in the overfilling of the capillary vessels and 
 a great flow of blood to the surface of the body. 
 This gives rise to a feeling of warmth. Every one 
 knows that in blushing the face is not only red but 
 hot. But this very flow of blood to the surface re- 
 sults in an increased radiation of heat, and the tem- 
 perature of the blood becomes lowered. Thus the 
 feeling of warmth produced by a dose of alcohol 
 is a deceptive one, for it really lowers the tempera- 
 ture of the body, and thus renders it less able to 
 resist external cold. The officers of Arctic expedi- 
 tions are unanimous in their opinion that the use 
 of alcohol in cold climates is injurious. 
 
 In hot climates, on the other hand, there is less 
 radiation from the body and less food is required 
 to keep up the animal heat. . The tissue changes 
 are less active than they should be for perfect 
 health, and, as alcohol tends to prevent such 
 changes, it increases the pernicious effects of the 
 high temperature. In army marches in tropical 
 climates it has been found that the drinkers of alco- 
 hol do not bear the heat so well as the abstinent, 
 and that they are more liable to sunstroke.* 
 
 Some striking instances have been given by 
 Dr. Parkes, and others, which illustrate these state- 
 ments. The Russian soldiers, for example, when 
 marching in winter use no spirits, and, what is 
 
 * It has also been shown that hard labor, either physical or men- 
 tal, is better done without alcohol than with it. This fact is recog- 
 nized and acted upon in the best training of athletes for races and 
 games, where such drinks are not allowed. 
 
FUiXCTIONS OF THE SKIN.— HYGIENE. 265 
 
 more, no man who has lately taken any is allowed 
 to start. The Swiss guides in Chamonix and the 
 Oberland are very sparing- in the use of spirits in 
 cold weather, finding it invariably hurtful. 
 
 In India, Annesley, after twenty years' service, 
 declared that dram-drinking killed more persons 
 than the climate or the sword. In the Kafhr war, 
 at the Cape of Good Hope, in 1852, *'a march was 
 made by two hundred men from Graham's Town 
 to Bloemfontein and back ; one thousand miles 
 were covered in seventy-one days ; the men were 
 almost naked, were exposed to great variations of 
 temperature (excessive heat during the day, while 
 at niofht water froze in a tent where twentv-one 
 men were sleeping), and got as rations only biscuit, 
 half a pound of meat, and what game they could 
 kill. For drink they had nothing but water. Yet 
 no man was sick until the end of the march, when 
 two men got dysenter}', and these were the only 
 two who had the chance of getting any liquor." 
 
 339. Amount of Perspiration. — The secretion of 
 the perspiration takes place constantly. Under or- 
 dinary circumstances, its amount is so small that it 
 does not collect in drops, but evaporates as soon as 
 it reaches the surface. This is called the " insen- 
 sible perspiration," and takes place at all times. Al- 
 though so gradually secreted and so quickly evap- 
 orated as to be unperceived by the individual, its 
 daily amount is surprisingly large. Lavoisier and 
 Seguin have found it to be a little less than two 
 pounds. This amount is immensely increased when 
 the body is exposed to an elevated temperature, and 
 the perspiration begins to run from the pores in 
 streams. It then often rises to the amount of a 
 
266 ORGANS OF PROTECTION. 
 
 pound an hour, and, as this great loss of fluid from 
 the body has to be resupphed from without, such 
 excessive perspiration is followed by excessive thirst. 
 
 340. Exposure to Dry Heat. — In order for evap- 
 oration to take place rapidly, the air must be dry 
 enough to absorb the vapor into which the water 
 passes. If the air be very dry, and contain very 
 little water, so that it is prepared to absorb an im- 
 mense amount of it, the human body can endure 
 without injury an incredibly high temperature. 
 Human beings have remained in ovens heated to a 
 temperature of from 350° to 600° Fahr., and re- 
 mained there while eggs and even beefsteaks were 
 cooked by their side.* 
 
 341. Exposure to Moist Heat. — If, on the other 
 hand, the air be already so saturated with watery 
 vapor that it can not take up much more (for its 
 capacity in this respect is limited), any great rise in 
 temperature causes extreme discomfort. It is on 
 account of this difference in the moisture of the 
 atmosphere, and consequent diminution or increase 
 of evaporation, that our physical comfort varies so 
 much on different days, when the thermometer reg- 
 isters the same temperature. For this reason, also 
 (the moister atmosphere), a temperature of 85° is 
 almost unendurable in London, while in New York 
 it is usually borne without discomfort. 
 
 * *' The workmen of the sculptor Chantrey were in the habit, accord- 
 ing to Dr. Carpenter, of entering a furnace in which the air was heated 
 up to 350° " (Dalton). A public performer, named Chabert, who called 
 himself the " Fire-King," is said to have exposed himself to a tempera- 
 ture of 600°, and remained in an oven heated to that degree while a 
 beefsteak was cooked by his side. In such experiments care has to be 
 taken that no metal, or other good conductor of heat, comes in contact 
 with the body, for if it does it will cause frightful burns. 
 
FUNCTIONS OF THE SKIN.— HYGIENE, 267 
 
 342. Respiration and Absorption through the 
 Skin. — There is also a certain amount of what 
 might be called respiration going on through the 
 skin — i. e., it has been shown, by inclosing one of 
 the limbs in an air-tight case, that the contained air 
 loses oxygen and gains carbon dioxide, showing 
 that an interchange of those gases takes place 
 through the skin, as well as through the lungs.* 
 It is also a fact, well known to physicians, that the 
 skin possesses the property of absorbing various 
 substances placed in contact with it.f 
 
 The skin is thus seen to be an exceedingly com- 
 plex organ, and to possess many very important 
 functions. There are certain peculiarities attend- 
 ing injuries and diseases of the skin which have 
 led many physiologists to think it has important 
 functions not yet discovered.:}: 
 
 The hygiene of the skin has mainly to do with 
 the questions of how to keep it cleansed from im- 
 purities, and how to regulate its temperature — i. e., 
 with bathing and clothing. 
 
 * The amount of carbon dioxide thrown off by the skin is esti- 
 mated at about one thirtieth of that exhaled from the lungs. 
 
 f Medicines are sometimes administered by rubbing them into the 
 skin. Castor-oil rubbed over the stomach will produce a medicinal 
 effect, and so will mercuiy. Infants who were too much exhausted by 
 disease to eat, or whose stomachs refused to retain food, have been 
 saved from death by rubbing nutritive substances, oils, etc., upon the 
 surface of the body. 
 
 X When the surface of the body is completely covered with a coat- 
 ing impervious to air, death ensues very rapidly. At the coronation 
 of Giovanni de' Medici (1475-T521) as Pope Leo X, a little boy was 
 covered with gold-foil to represent a cherub, and add to the splendor 
 of the ceremonies. He became almost immediately ill, however, and, 
 in spite of all that was done, died in a few hours, because the gold and 
 varnish were not removed. 
 
268 ORGANS OF PROTECTION. 
 
 343. Necessity of cleansing the Skin. — The im- 
 purities on the surface of the skin come mainly from 
 three sources : i. The perspiration contains a small 
 amount of solid matter, mostly mineral, which is 
 deposited upon the skin and left there as the water 
 evaporates. 2. The fatty secretion of the sebaceous 
 glands is constantly being poured out in small quan- 
 tity, and dries upon the surface. 3. The epidermal 
 scales in the outer layer of the skin are being con- 
 tinually shed, pushed off, as it were, by the cells 
 developing under them, and most of them fall away 
 in the form of a fine, branny dust, which clings to 
 the under-clothing, and is brushed and washed from 
 other parts of the body. A certain amount of this 
 refuse epidermis is caught in the drying perspira- 
 tion and sebaceous secretion, and so remains, as it 
 were, glued to the surface. These different impuri- 
 ties tend to choke the mouths of the perspiratory 
 and sebaceous glands, and prevent their free action. 
 The surface of the body must be kept free from 
 such accumulations. 
 
 Much obscurity has been unnecessarily thrown 
 around the subject of the ordinary bath. The rules 
 regarding it are in reality few and simple. The dis- 
 cussions mainly relate to the time, duration, and 
 temperature of the bath, and the results may be 
 summed up thus : 
 
 344. Effect of a Cold Bath. — The first effect of a 
 cold bath is to produce a shock to the nervous sys- 
 tem, resulting in the contraction of the blood-vessels 
 at the surface of the body. This shock in a healthy 
 person is soon followed by a reaction, in which the 
 heart acts with more vigor than usual, and the con- 
 tracted blood-vessels are again filled with blood. 
 
FUNCTIONS OF THE SKIN.— HYGIENE. 269 
 
 The surface of the body then becomes ruddy or 
 rosy, and a pleasurable glow is felt by the bather. 
 The bath should end while this glow of reaction 
 continues, for, if it is allowed to pass away, it is 
 succeeded by a feeling of lassitude and depression, 
 which may last for the rest of the day, and indicates 
 a certain degree of exhaustion of the nervous sys- 
 tem. The after-glow may be increased, and the 
 good effect of the cold bath enhanced, by a brisk 
 rubbing of the surface with the hands or a towel. 
 
 345. Effect of a Warm Bath. — The first effect 
 of a warm bath is to dilate the superficial blood- 
 vessels and cause a fiow of blood to the skin. This 
 produces a general relaxation of the pores of the 
 glands, tends to increase their activity, and in 
 weakly persons there is slight stimulation of the 
 nervous system. After such a bath, the skin being 
 full of blood and in a relaxed condition, exposure 
 to the cold air is dangerous, and the bather should 
 not go out-of-doors until the surface of the body is 
 perfectly dry, and any feeling of languor has disap- 
 peared. 
 
 346. Rules for Bathing. — Briefly stated, then, 
 these are the rules for sfuidance in the bath : 
 
 Do not bathe ivithin three hours after a meal, as the 
 change in the circulation produced by the change 
 in temperature of the surface of the body interferes 
 with the proper distribution of blood in the digest- 
 ive organs. 
 
 Do not bathe in cold ivater, if you have found by 
 previous trials that you always have a chilly feeling- af 
 terzvard. This is a matter to be determined wholly 
 by personal experience, and, when any person finds 
 that a particular kind of bath makes him uncom- 
 
270 
 
 ORGANS OF PROTECTION. 
 
 fortable afterward, it is the part of prudence to 
 shun it thenceforth. As a general rule, it may be 
 stated that a vigorous person will feel better after a 
 cold bath, and a feeble person after a warm one, if 
 not too prolonged. 
 
 Do not remain in the bath too long. If you feel 
 chilly when you come out, the bath will do you 
 more harm than good. As a general rule, from ten 
 to fifteen minutes is long enough for a warm bath, 
 and five minutes for a cold one. 
 
 347. Washing the Hands and Face. — The hands 
 and face are washed more frequently than any other 
 part of the body, because they are more exposed 
 and become dirty sooner. If they can be kept clean 
 with water alone, soap should be avoided, because 
 it unites with the fatty matters on the surf-ace, a cer- 
 tain amount of which is natural and necessary to 
 keep the skin soft and pliable. Soaps that contain 
 an excess of alkali "^ are particularly injurious, be- 
 cause they not only remove too much of the seba- 
 ceous secretion, but irritate the surface and even 
 produce eruptions. After the hands have been 
 washed, especially in cold weather, they should be 
 carefully and thoroughly dried before exposing 
 them to the cold air. It is the neglect of this pre- 
 caution, together with the excessive use of soap, 
 that causes " chapping " of the hands. The soap 
 removes the fatty matter from the epidermis, thus 
 depriving it of its pliability, and the water, espe- 
 
 * Soap is made by boiling fat with potash or soda ; the former 
 makes soft soap and the latter hard soap, such as is commonly used in 
 the toilet. If the proportions of these ingredients are not precisely 
 right, there will be an excess of one of them in the product, and this 
 excess is always alkaline, because special care is taken to neutralize all 
 the fat. 
 
FUNCTIONS OF THE SKIN.— HYGIENE, 271 
 
 daily if it is warm, is absorbed to a certain extent 
 by the outer cells of the epidermis, so that they swell 
 a little and become softer than before. The epider- 
 mis thus becom.es less elastic and less tenacious. 
 If it is suddenly exposed to the cold while in this 
 condition, the outer layer contracts and tears apart, 
 in some places making cracks, which often extend 
 down to the derma, and give rise to considerable 
 suffering. Then fatty matter (grease, vaseline, etc.) 
 has to be supplied to take the place of the natural 
 secretion that has been so unthinkingly removed. 
 
 To keep the skill of the face and hands smooth and 
 pliable, therefore, soap should be used sparingly,* 
 and they should be thoroughly dried after wash- 
 ing. 
 
 348. Care of the Scalp. — The scalp should also be 
 kept clean. The epidermis is shed constantly in 
 this region, as well as in other parts of the body, 
 and, together with the dried sebaceous secretion, 
 causes what is known as " dandruff." f The hair 
 should be dressed with a brush that is not stiff 
 enough to scratch the scalp, and the comb should 
 be used only to part the hair and disentangle it, 
 never to relieve itching. Constant scratching of 
 the scalp increases the trouble it is designed to re- 
 lieve, and makes it rough and inflamed, just as the 
 same treatment will affect the back of the hand or 
 the cheeks. It is well to wash the scalp thoroughly 
 with cold water at least once a week, drying the 
 
 * The highly-scented toilet-soaps are often made of rancid fat, and 
 injure the skin. The best soap for ordinary use is the white Castile 
 soap, of Spanish or Italian manufacture, which is made of sweet olive- 
 oil and not perfumed. 
 
 •f Extreme degrees of dandruff are the result of a disease of the 
 scalp, and are often difficult to cure. 
 
2;2 ORGAiXS OF PROTECTION. 
 
 hair before going out-of-doors. The hair of girls 
 should never be cut, if it is possible to avoid it, as 
 it is the universal testimony that it never grows as 
 long after cutting as if it is left alone. 
 
 349. Care of the Nails. — The finger-nails should 
 be carefully trimmed,'^ but never cut close to the 
 flesh. If they are cut too short, not only is the deli- 
 cacy of touch affected, but the ends of the fingers 
 will become club-shaped and ugly. The flesh about 
 the roots and sides of the nails should not be allowed 
 to adhere to them, as it is pulled along and stretched 
 as the nail grows, and produces " hang-nails." The 
 white spots which often appear on the nails are 
 caused by slight blows on the root of the nail dur- 
 ing its formation, and therefore are most common 
 in children and in persons whose occupation exposes 
 their hands to such violence. They are of no spe- 
 cial importance. 
 
 350. Clothing. — The object of clothing is to main- 
 tain an equable temperature at the surface of the 
 body. For this purpose the best material to be 
 worn next the skin is a poor conductor of heat. 
 Woolen material, from its porous texture, conducts 
 heat very poorly, and flannel should therefore al- 
 ways be worn next the body, summer and winter. 
 No other material can be compared with it for pro- 
 tecting the surface against sudden changes of tem- 
 perature. Linen, on the other hand, is such a good 
 conductor of heat, that its use next the skin is 
 absolutely dangerous. Cotton is intermediate be- 
 tween the two. As for the outside clothing, that 
 
 * It is better to soften the nails slightly in warm water before cut- 
 ting ; otherwise they will often split or break at the edge, especially 
 in cold weather- 
 
FUNCTIOXS OF THE SKIN.— HYGIENE. 2^7, 
 
 may be safely left to be decided by the comfort 
 and taste of every individual. 
 
 The clothing that has been worn during the day 
 should be entirely removed at night on going to 
 bed. The under-clothing, which has been for so 
 many hours in contact with the surface of ti. e skin, 
 is more or less loaded with the matters cast off by 
 it, and, if it is not changed daily, should at least 
 be thoroughly aired during the night. 
 
 A shoe that can not be worn continuously dur- 
 ing the Avaking hours from the time it is first put 
 on, should not be worn at all. The habit of " break- 
 ing-in" new shoes inevitably results in distortion 
 of the feet and the development of corns. High 
 heels are also bad, because the weight of the body 
 drives the toes down into the narrow end of the 
 shoe, and causes the painful and unnecessary affec- 
 tion known as ''in-growing" nails. 
 
 Always wear, therefore, a gooel noi:-conduetor of Jieat 
 next the skin. 
 
 Never wear any artiele of dress that pinches, for 
 it \\\\\ inevitably result in distortion or disease, or 
 both, especiall}' in the young, whose bones are yield- 
 ing and whose organs are not fully formed, and need 
 perfect freedom for their healthy development. 
 
PART VI. 
 ORGANS OF PERCEPTION. 
 
 CHAPTER I. 
 
 TOUCH— TASTE — SMELL. 
 
 351. Structure of the Papillae. — The sense of 
 touch has its seat in the papillae of the skin. The 
 nerves, on entering the papillse, end in certain oval- 
 shaped bulbs, which are very small, and are com- 
 posed of connective tissue, quite firm in texture, but 
 containing a soft material at the center. The nerve, 
 on entering this bulb, loses its medullary substance 
 (or myelin), and only the axis-cylinder is continued 
 into the center. The papillae do not all contain 
 such bulbs or corpuscles, but, as they are found 
 in the greatest numbers in places where the sensi- 
 bility is most acute, it is reasonable to suppose that 
 their function is intimately connected with the sense 
 of touch. 
 
 352. The Sense of Touch. — By this sense we 
 gain our knowledge of hardness and softness, heat 
 and cold, roughness and smoothness. The sensi- 
 tiveness of the skin, as every one knows, varies very- 
 much in different parts of the body, and attempts 
 have been made to invent some means of measuring 
 accurately the perfection of this sense. The most 
 
TO UCH— TA STE- - SMELL. 2 7 5 
 
 usual method is to apply the points of a pair of 
 compasses to various spots on the surface of the 
 body, and see at what distance apart the two points 
 can be perfectly perceived to be two and not one. 
 At the tips of the fingers thev can be separately 
 distinguished when only one eighteenth of an inch 
 apart, while at the small of the back they must be 
 separated to a distance of nearly two inches before 
 they will cease to seem one point. Between these 
 extremes there are many intermediate grades of 
 sensation. "^^ 
 
 353. Deception by the Senses. — It is a remark- 
 able fact that the extremes of any kind of sensation 
 can not readily be distinguished from each other. 
 A piece of iron at a white-heat and a frozen solu- 
 tion at 70° below zero will produce much the same 
 sensation in the part touching them. But it is not 
 so familiar a fact that, after all, the conscious sense 
 really lies, not in the termination of the nerve, but 
 in the nerve-center which receives the impulse from 
 it, and that, if this be out of order, the sense may be 
 deceptive. This fact of our liability to be deceived 
 by our senses applies to all of them — the sense of 
 touch as well as to others. A single illustration 
 will sulifice. It might seem as if any person would 
 be able to determine by his feelings whether he 
 were hot or cold, and yet it is well known to physi- 
 cians that, in the chill of fever and ague, when the 
 sufferer, with blue lips and chattering teeth, wants 
 
 * The most delicately sensitive part is the tip of the tongue, where 
 the two points are distinguished when only one thirtieth of an inch 
 apart. As every one knows, a fine hair, which can not be felt by the 
 finger, or only with the greatest difficulty and uncertainty, is clearly 
 perceived by the tongue. 
 
2/6 ORGANS OF PERCEPTION. 
 
 to be covered deep with blankets, his temperature 
 by the thermometer is much higher than in health, 
 often running up to io6° Fahr.* 
 
 354. The Special Senses. — The special senses are 
 all modifications of the sense of touch, and were 
 probably developed out of it. They differ, how- 
 ever, from it, and from one another, in the fact that 
 in each a special kind of sensation is roused in re- 
 sponse to whatever form of stimulus. Any stimu- 
 lus to the retina of the eye, for example, produces 
 only the sensation of light — no matter whether it be 
 light, or a blow, or an electric current — and so with 
 the other special senses (excepting that of taste, as 
 hereafter mentioned). In the eye and the ear, the 
 apparatus for the special appreciation of stimuli 
 forms a highly complicated and delicate mechan- 
 ism. In the description of these special senses, we 
 shall begin with the one which is least removed 
 from the sense of touch, and end with the one in 
 which sense-perception is the most highly devel- 
 oped. 
 
 355. The Tongue. — The sense of taste differs 
 less from ordinary sensibility than any of the other 
 senses. It is located chiefly in the tongue, but it 
 has been found, by careful experiments, that we 
 can perceive the flavor of substances also with the 
 soft palate and a small portion of the throat. The 
 tongue is a muscular organ of great mobility, and is 
 supplied with three nerves from the brain. One of 
 
 * An easy way to satisfy one's self of the deceptive nature of our 
 sensations, and of the fact that they must often be corrected by the 
 judgment, is this : Put one hand into cold water, and the other into 
 warm ; take them out quickly, and plunge them both into water a little 
 cooler than the warm water just used ; it will be found that this v/ater 
 will seem cold to one hand and warm to the other. 
 
TO UCH— TA S TE— SMELL. 277 
 
 these nerves presides over its motions, while the 
 other two are sensitive nerves, one of which is dis- 
 tributed to the anterior two thirds of the surface of 
 the organ, and the other to the posterior portion 
 (Fig. 63). The exact method in which these nerves 
 terminate is not known, but the surface of the tongue 
 
 Fig. 63. — Diagram showing the distribution of the ner\-es of taste in the 
 
 toneue. 
 
 is covered with small papillae, which can be easily 
 seen with the naked eye, and the delicate extremi- 
 ties of the nerves are known to terminate in these 
 papillae. It is well known that no substance can be 
 perceived by the taste unless it is soluble, and this 
 renders it almost certain that the matter tasted 
 comes into actual contact with the end of the 
 nerve. 
 
 356. The Sense of Taste. — The nerves of taste, 
 in distinction from most nerves of special sense, 
 also convey sensation like the nerves of general 
 sensibility. This fact makes it a little difficult to 
 distinguish between things felt by the tongue and 
 things tasted. It is considered by many that there 
 are in all only four modifications of the sense of taste^ 
 viz., sweetness, sourness, sa/tness, and bitterness. To 
 19 
 
278 ORGANS OF PERCEPTION. 
 
 these qualities, or savors, others add such savors 
 as alkaline, styptic, etc., which are compound sen- 
 sations, and it is, to say the least, very doubtful 
 whether they should be classed as distinct savors. 
 Qualities which are really the result of feeling, and 
 not of taste, although perceived by the tongue and 
 palate, are pungency, starchiness, piquancy, oiliness, etCo 
 Another source of error in estimating savors lies in 
 the fact that there is a communication between the 
 nose and mouth through the throat. It is some- 
 times very hard to distinguish between what we 
 perceive by the sense of smell and what we taste. 
 This is in some degree the case with liquids which 
 have an aroma or bouquet, but it may be shown that 
 the aroma is perceived entirely by the sense of smell, 
 by closing the nostrils while tasting the aromatic 
 substance. It will then be found that the aroma 
 disappears, although the communication between 
 the nose and throat still remains open. The reason 
 for this will be explained under the section describ- 
 ing the sense of smell. 
 
 357. Peculiarities of the Sense of Taste. — It has 
 been stated that the front and back part of the 
 tongue are supplied by different nerves. This state 
 of things gives rise to a curious phenomenon, viz., 
 that certain substances have a decidedly different 
 taste when placed on one part of the tongue from 
 what they have on the other. A few examples of 
 this will suffice : 
 
 \i potassium chloride be put upon the anterior por- 
 tion of the tongue, it tastes saltish, but on the poste- 
 rior, sweetish. Sodium sulphate, on the anterior portion, 
 is salt, on \h.Q posterior, bitter. Alum, on the anterior 
 surface, tastes acid2<Xi<i\ styptic, while on i\i^ posterior^ 
 
TO UCH— TAS TE— SMELL, 
 
 2/9 
 
 it has a decidedly sweetish taste, with no acid qual- 
 ity whatever. 
 
 The sense of taste persists for a short time after 
 the substance tasted is removed. This is probably 
 because the portion of the substance which pene- 
 trated the mucous membrane and affected the nerve 
 has not all been taken up and carried away by the 
 circulation. For this reason, it is impossible to ap- 
 preciate the true savor of different substances by 
 tasting them in rapid succession. The impression 
 made by the first should be allowed to disappear, 
 and only remain in the memory, before the sec- 
 ond is tasted. This only applies to delicate flavors. 
 Where the flavors are coarse and pronounced, the 
 slight masking of one by the other often inter, 
 feres very little with a correct judgment of their 
 character. 
 
 The flavor of any substance is perceived in ex- 
 act proportion to the amount of surface affected by 
 it. So we frequently see persons smacking their 
 lips and pressing their tongues against the roof of 
 the mouth, the better to appreciate a flavor, by 
 spreading the morsel over a larger surface. The 
 use of the sense of taste in the detection of impure 
 and unwholesome food has already been referred 
 to. In addition to this function, it affords us great 
 physical pleasure, although it is generally thought 
 to be of a low order. 
 
 The sense of taste, like that of touch, requires 
 actual contact with the substances tasted, and can 
 give us no knowledge respecting substances at a 
 distance from our bodies. We now come to a sense 
 which is a step higher in the scale, for it gives us 
 knowledge of substances at a distance, and it does 
 
28o 
 
 ORGANS OF PERCEPTION. 
 
 this by means of material emanations which often 
 can not be detected in any other way. 
 
 358. The Sense of Smell. — The sense of smell 
 resides in the mucous membrane lining the upper 
 portion of the cavity of the nose. This portion of 
 membrane is supplied by the olfactory nerve, which 
 does not convey ordinary sensation, as do the nerves 
 of taste, but carries to the brain onl}^ the special 
 sensation of smell. The nerve is distributed to the 
 upper third of the nasal passages, and the rest of 
 the interior of the nose is supplied by nerves of 
 ordinary sensation (Fig. 64). 
 
 The amount of any substance required to affect 
 the sense of smell is inconceivably minute. There 
 
 Fig. 64. — The interior of the left nasal passage. The fan-like expansion of 
 nervous fibers is the olfactory nerve. The other nerves shown are nerves 
 of ordinary sensation. 
 
 is no chemical or physical means known by which 
 it can be detected in many cases. A grain of musk 
 will perfume a room for months, and lose nothing 
 apparently in weight. 
 
TOUCH— TASTE— SMELL. 28 1 
 
 In order to affect the sense of smell, the odorous 
 air must be drawn through the nose. If the air 
 in the nasal passages remains stationary, we smell 
 nothing. This is the reason why closing the nostrils 
 prevents our appreciating aromatic substances in the 
 mouth. For this reason, also, we sniff at whatever 
 has a delicate or faint odor, and, by increasing the 
 rapidity of the air-current through the nose, we add 
 to our appreciation of the odor."^ This is very no- 
 ticeable in the lower animals. 
 
 It is necessary to distinguish between substances 
 which really affect the sense of smell and those 
 which merely irritate the mucous membrane. INIany 
 substances affect both senses — that of smell and that 
 of general sensibilit}". Pepper, for instance, has a 
 clearly distinguishable and peculiar odor of its own, 
 which is appreciated by the olfactory nerve, and it 
 also irritates the nerves of general sensibility. Aui- 
 inoniay if pure, is merely an irritant, and has no 
 proper odor of its own. 
 
 359. Relative Acuteness of the Sense of Smell. — 
 The sense of smell among civilized persons is not 
 educated, and is rather defective. Among savages 
 it is much more acute. Humboldt states that cer- 
 tain South American Indians can detect the ap- 
 proach of a stranger, in a dark night, bv the sense 
 of smell, and will also tell whether he is a white 
 man, an Indian, or a negro. But the lower animals 
 far surpass man in this as well as in most other 
 senses. The keenness of the dog's scent is pro- 
 
 * The distribulion of the olfactory nerve in the upper part of the 
 nose also makes it necessary to sniff at faint odors, for otherwise the 
 air containing them might pass through the lower passages of the nose 
 into the throat, without reachinsi the nerve of smell. 
 
282 ORGANS OF PERCEPTION. 
 
 verbial, and he depends much more upon his sense 
 of smell, for recognition of his master, than on his 
 sense of sight. 
 
 The sense of smell, like the sense of taste, acts 
 as a sentinel to guard against the introduction of 
 improper food into our stomachs. It also warns 
 us of impurities in the air. After long exposure, 
 however, to a particular odor, the sense appears to 
 become blunted, and that even when the odor is a 
 peculiarly disagreeable one. It seems as if, when 
 its warnings came to be disregarded, it ceased to 
 give any more. 
 
 The sense of smell appreciates a great number 
 of distinct odors, and from delicate and fragrant 
 ones we receive a great deal of pleasure. This 
 sense, undoubtedly, occupies a higher plane than 
 the sense of taste, and a delight in pleasant per- 
 fumes marks a higher sense of sesthetic gratification 
 than a devotion to the pleasures of the table. 
 
CHAPTER II. 
 
 HEARING. 
 
 360. The Sense of Hearing. — As we ascend in 
 the scale, we come to a sense which does not in- 
 form us of what is taking place in the world out- 
 side of us, by actual contact with matter, like the 
 senses of touch and taste ; nor by contact Avith 
 emanations from matter, like the sense of smell ; 
 but impressions are produced upon it by means of 
 motion in the atmosphere which surrounds us. 
 This is the sense of hearing. Every movement of 
 every form of matter gives rise to waves or vibra- 
 tions in the air, which lies in contact with the mov- 
 ing substance. These atmospheric waves are re- 
 ceived, and the impression made by them is trans- 
 mitted to the brain bv a special apparatus. 
 
 361. The External Ear. — The ear (Fig. 65) is 
 usually described by anatomists as consisting of 
 three divisions — the external ear, the middle ear, and 
 the internal ear. The appearance of the external 
 ear is familiar to all. It has a somewhat shell-Hkc 
 form, has numerous ridges and hollows, and is com- 
 posed principally of cartilage covered with skin. 
 This external ear serves to collect the waves of 
 sound, and direct them toward the internal parts. 
 In animals this organ is very movable, and, during 
 
284 ORGANS OF PERCEPTION. 
 
 their waking hours, is generally in motion, to catch 
 sound from various directions. In the human be- 
 
 FlG. 65. — Section of the ear, showing the relative positions of the external, 
 middle, and internal ear. 
 
 mg there are three small muscles attached to the 
 external ear — one behind, one above, and one in 
 front. These muscles, however, are practically use- 
 less, and very few persons have any voluntary con- 
 trol over them. Those who do, can cause the mus- 
 cle in the rear to contract, and move the ear slightly 
 backward, but the motion is limited, and answers 
 no purpose. 
 
 362. The Middle Ear. — From the external ear a 
 canal passes directly inward, toward the interior of 
 the skull, for a distance of about an inch and a 
 quarter. At its inner extremity it is closed by a 
 thin membrane, called the membrane of the tympa- 
 num, or the drum of the ear ; and on the other side 
 of this membrane is a small cavity in the bone, about 
 
HEARING. 285 
 
 a third of an inch long, a quarter of an inch in height, 
 and a sixth of an inch wide, called the tympanum,'*' or 
 middle ear. The membrane of the t3'mpanum is 
 stretched like the head of a drum, and answers some- 
 what the same purpose. Upon this membrane the 
 waves of air strike, causing it to vibrate ; and this 
 vibration of the membrane is the first step toward 
 bringing the air-waves, or the impulse given by them, 
 into contact with the nerve of hearing. And here 
 we remark that, in order for the vibration of a mem- 
 brane to be perfect, the air on both sides of it must 
 be of the same degree of density during the vibra- 
 tion. In the common drum this is provided for by 
 having a hole in the side, to allow free passage for 
 the air in and out. In the cavity of the middle ear 
 it is provided for by a short tube, called the Eusta- 
 chian f tube, leading into the throat. This tube is 
 about an inch and a half or two inches long, and, 
 for perfect hearing, it is necessary that the air 
 should pass in and out through it with freedom. 
 
 363. The Bones of the Ear. — In the cavity of the 
 middle ear is a chain of minute bones, three in number, 
 which altogether only weigh a few grains. One of 
 them is attached to the membrane of the tympanum, 
 another is attached to another membrane stretched 
 in drum-like form across a small hole on the oppo- 
 site side of the middle ear, and the third unites the 
 other two. These small bores have very minute 
 muscles attached to them in such a way that by their 
 contraction or relaxation the bones are made to as- 
 sume slightly different positions, and the membranes 
 
 * Tym'panum, a Latin word meaning dnim. 
 
 \ Eustachian, from Bartolomeo Eustachi. a celebrated Italian anat- 
 omist (died 1574), who first described it. 
 
286 ORGANS OF PERCEPTION. 
 
 to which they are attached are made more or less 
 tense, and therefore more or less sensitive to sounds. 
 It is probable that these muscles are somewhat un- 
 der the control of the will, and that some of the 
 effort of which we are conscious when we strain our 
 attention to detect a faint sound, is due to their 
 active contraction. 
 
 364. The Internal Ear. — The second membrane 
 above spoken of, which is smaller than the mem- 
 brane of the tympanum, closes the passage between 
 the middle and internal ears. The internal ear or 
 labyrinth is exceedingly complicated, and the func- 
 tions of its parts are not yet well understood. The 
 difficulties of investigation are immense, partly on 
 account of the minuteness of the organs and partly 
 because they are situated so deeply in the bones of 
 the skull and are so near the brain. It is sufficient 
 to say that the internal ear is made up of many 
 winding channels and spiral tubes, which go by the 
 names of the cochlea, the semicircular canals, and a 
 cavity called the vestibule, with which the others 
 communicate. All these passages are filled with a 
 watery fluid, and on their walls and througli their 
 interiors are distributed the filaments"^ of the nerve 
 of hearing, the auditory nerve. As has been said, the 
 cavity of the vestibule is separated from that of the 
 middle ear by a thin membrane, to which one of 
 the bones of the middle ear is attached. Thus, any 
 vibration or impulse imparted to this membrane 
 produces a corresponding pressure on the nerve of 
 hearing, through the medium of the watery fluid 
 which fills all parts of the internal ear. 
 
 365. Recapitulation. — Thus the air-waves enter- 
 
 * Filaments, small, delicate, thread-like fibers. 
 
HEARING. 287 
 
 ing the external ear strike upon the membrane of 
 the tympanum and put it in vibration. These vi- 
 brations are communicated through the chain of 
 bones to the inner membrane, which is also made 
 to vibrate. These vibrations, again, are communi- 
 cated to the watery contents of the internal ear, 
 and they in turn press directly upon the extremities 
 of the auditory nerve, which conveys the impulse 
 to the brain. And in this way we hear sounds. 
 
 366. Different Qualities of Sound. — When we 
 hear sounds, Ave distinguish many different quali- 
 ties in them, such as pitch, quality, timbre, degree, 
 etc. These differences mainly depend upon the 
 different length, rapidity, height, and character of 
 the air-waves. They are perceived, in a greater or 
 less degree, by every person, but the ease and ac- 
 curacy with which they are appreciated may be in- 
 creased by education. The appreciation of musical 
 sounds, for instance, may be immensely increased 
 by practice and proper training. 
 
 367. Determination of the Source of Sound. — 
 Besides the perception of the foregoing differences 
 in sounds, which is partly the result of natural en- 
 dowment and partly that of training, there is an- 
 other fact with regard to sound which has given 
 rise to considerable discussion. It is the power we 
 have of determining with more or less accuracy the 
 locality from which a sound comes. Some physi- 
 ologists have supposed that, as the semicircular ca- 
 nals, three in number, are always placed at different 
 angles, they serve in some way, not easilv explained, 
 to indicate to us the direction from which the air- 
 waves come.* This view has been supported by 
 
 * It has been lately suggested that the semicircular canals havr 
 
288 ORGANS OF PERCEPTION. 
 
 arguments of some plausibility, but it is now the 
 accepted view that our knowledge of the direction 
 and distance of the source of any sound is the re- 
 sult of past experience. We judge partly by the 
 loudness of a familiar noise, partly by the greater 
 impression on one ear than on the other, partly by 
 the difference in the sound when we turn the head 
 a little one way or the other, the direction of the 
 wind, and a hundred other influences, which have 
 become a part of our experience. If we can not, 
 for any reason, use enough of these methods, we 
 find ourselves unable to locate even a loud and dis- 
 tinct sound ; e. g., it is very difficult to tell in what 
 part of a closed room to look for a chirping cricket. 
 368. Ventriloquism. — The art of ventriloquism de- 
 pends upon an adroit use of these methods in such 
 a way as to deceive. The ventriloquist slyly robs 
 us of all the means which generally serve us to 
 detect the origin of a sound. He speaks without 
 moving his lips ; he modulates his voice so that it 
 appears to come from a distance, on account of its 
 faintness ; he calls the attention of the spectator, 
 either by word or by gesture, to the point from 
 which he wishes him to expect the sound, and 
 makes clever use of the slight shades in timbre and 
 pitch, which all of us can distinguish, but which it 
 requires great skill and practice to reproduce as 
 
 something to do with the sense of direction, and with the preservation 
 of the bodily equilibrium. It has been found that certain obscure 
 nervous symptoms, attended by inability to maintain equilibrium, have 
 resulted from injury to these parts. There is a disease of these or- 
 gans, called Meniere's disease, from the man who first described it, in 
 which giddiness, as well as deafness, is a prominent symptom. It is 
 probable that the frequent attacks of vertigo, with increasing deafness, 
 from which Dean Swift suffered, v/ere caused by this diiease. 
 
HEARING. 289 
 
 professors of this art are able to. The common 
 idea that a man's voice can actually be projected 
 or thrown into a spot twenty feet from his larynx 
 is the idea of pure ignorance, and, as soon as one 
 understands the mechanism of the voice, is seen to 
 be as impossible as for any one to see through a 
 solid stone wall, a thick envelope, a book-cover, or 
 anything else through which no light can pass. 
 
 369. Care of the Ear. — The ear is, in almost all 
 its parts, a very delicate organ, but, excepting the 
 external ear, it is so deeply set in bone that it is 
 not very liable to injury ; and yet neglect of the 
 organ or ignorant tampering with it may result in 
 permanent and irreparable harm. The tube leading 
 inward from the external ear, called the external 
 auditory canal, is sometimes entered by insects. Its 
 walls are moistened by a peculiar secretion, called 
 " wax," produced by small glands just beneath the 
 skin w^hich lines it. This wax is somewhat sticky, 
 and is intensely bitter, and, together with certain 
 short hairs near the outlet of the canal, serves to 
 protect the membrane of the tympanum from the 
 inroads of insects.^ The wax has sometimes a 
 tendency to accumulate and interfere with the 
 hearing ; and some persons are in the habit of 
 cleaning their ears with ear -scoops. This is an 
 exceedingly dangerous practice, and can not be 
 too severely condemned. The ear is a delicate or. 
 gan, and must be treated delicately by a person 
 who thoroughly understands its anatomy. 
 
 370. Danger of Colds in the Head. — The dan- 
 
 * Insects can sometimes be coaxed out of the ear by holding a light 
 in front of, and quite near, the external opening. They are attracted 
 by the light, as moths are, and turn round and crawl toward it. 
 
290 
 
 ORGANS OF PERCEPTION. 
 
 ger of injury to the hearing apparatus through the 
 Eustachian tube is principally from inflammation. 
 Colds in the head almost always affect the hearing 
 in some degree, on account of the swelling of the 
 membrane around the mouth of the tube. But the 
 inflammation may not stop at this point. It some- 
 times travels along the tube to the middle ear, and 
 when the exceedingly delicate mucous membrane of 
 the middle ear becomes affected, there is usually 
 more or less permanent impairment of the sense of 
 hearing. The little chain of bones becomes stiffened 
 by the disease, just as an elbow or knee does after 
 an attack of rheumatism, and so they conduct the 
 vibrations of the membrane of the tympanum with 
 less force and accuracy. On the slightest indication, 
 therefore, of inflammation of the Eustachian tube, 
 as indicated by unusual dullness of hearing, during 
 an acute catarrh of the nose or throat, a physician 
 should be consulted. The process just described 
 gives rise, in the climate of New York, to about 
 two thirds of all the cases of deafness. 
 
 Owing to the congestion of the mucous mem- 
 brane of the nose and throat produced by alcohol 
 and tobacco, it is found that deafness of varying 
 degree is quite common among drinkers and smok- 
 ers. 
 
CHAPTER III. 
 
 SIGHT. 
 
 371. The Sense of Sight. — We now come to the 
 highest and most perfect of all the senses, that of sigJit. 
 The four senses previously considered all depend 
 on material contact, in a greater or less degree, for 
 their appreciation of the external world. Even the 
 last sense considered, that of hearing, depends on 
 contact with waves in the air, which is a form of 
 matter, although attenuated. But we now have to 
 do with an organ which perceives external objects 
 through the intervention of light, and light is some- 
 thing which can not be felt or weighed, or detected 
 in any other way than by sight. There have been 
 many theories regarding the nature of light, but 
 the one most in favor at the present day is the ivave 
 theory^ or widiilatory tJicory^ so called. 
 
 372. The Nature of Light. — According to this 
 theory, the universe is pervaded by an exceedingly 
 subtile form of matter called the ctJicr, and light 
 consists of waves propagated through this ether' 
 with tremendous rapidity. The average number 
 of vibrations in a second is estimated to be over 
 500,000,000,000,000, and they travel at the rate of 
 about 187,000 miles per second. The wave theory 
 of light is only a theory, and the existence of the 
 
592 
 
 ORGANS OF PERCEPTION. 
 
 extremely attenuated form of matter called ether, 
 which can neither be weighed, seen, heard, nor felt, 
 but only postulated from certain phenomena sup- 
 posed to depend upon it, is only inferred ; but still 
 this theory explains almost all the phenomena of 
 light, and, until some better one is suggested, must 
 be retained as a working hypothesis. 
 
 From these facts, we can judge of the extraor- 
 dinary delicacy of the eye as an organ of sense. 
 Here is a stimulus, of unknown origin, which can 
 traverse the widest regions of space, which enables 
 us to appreciate the existence and form and even 
 the structure of bodies which are billions of miles 
 away from us, and gives us more knowledge of the 
 external world, perhaps, than we obtain through all 
 our other senses together, and yet its real nature is 
 as hidden and mysterious and impalpable as the na- 
 ture of our consciousness. Let us now examine the 
 structure of the organ which perceives this strange 
 stimulus and enables it to affect our brain. 
 
 373. Situation of the Eye. — The eye is situated 
 in a cavity called the orbit, surrounded by bone ex- 
 cepting in front, and padded all about with fatty 
 and muscular tissues, so that, although it is pro- 
 tected from injury by an unyielding bony case, it 
 still reposes on a soft and elastic bed. 
 
 374. Structure of the Eyeball. — The eyeball 
 (Fig. 66) is nearly spherical, and about an inch in 
 diameter. It is formed of three membranes, ar- 
 ranged concentrically one within the other, and the 
 interior is filled with certain structures necessary to 
 vision. The outer membrane is called the sclerotic'^ 
 
 * Sclera t'ic, from the Greek (TKAripds, Aard, because it is the hardest 
 and toughest coat of the eye. 
 
SIGHT, 
 
 293 
 
 coat, and in front, where it is visible, constitutes 
 what is commonly known as the white of the eye. 
 
 Fig. 66. — Horizontal section of the right ej'e, showing the relative poshion 
 
 of its parts. 
 
 It is composed of white, fibrous tissue, and is ex- 
 ceedingly strong, tough, and elastic. It surrounds 
 the whole eyeball, excepting in front, where a trans- 
 parent membrane, about ^th of an inch thick, is set 
 into it like a watch-s^lass in the case. The front of 
 the eye must of course be transparent for the ad- 
 mission of light. This portion of the eye is called 
 the cornea:^ 
 
 * Cornea, from the Latin cor nu, a horn, because of its resemblance 
 to transparent horn. 
 20 
 
294 ORGANS OF PERCEPTION, 
 
 Just inside the sclerotic coat is another coat, 
 called the choroid,^ which covers the whole interior 
 of the eye, excepting that portion bounded by the 
 cornea. This coat is very plentifully supplied with 
 blood-vessels, and with immense numbers of minute 
 cells, filled with coioring-matter, so that it appears 
 of a dark-brown or chocolate color, and in some 
 persons almost black. Inside this choroid coat, 
 again, is the retina,\ which is an exceedingly deli- 
 cate and complicated membrane made up of nerv- 
 ous tissue, and upon which the impressions of light 
 are received. The retina is spread over about two 
 thirds of the inner surface of the eyeball, not reach- 
 ing quite as far forward as the sclerotic and choroid 
 coats. 
 
 375. The Internal Parts of the Eye. — The mem» 
 branes above mentioned form, so to speak, the in- 
 casement or shell of the eyeball. The bulk of the 
 interior oj the eye is formed by the vitreous humor. % 
 This is a soft, semi-fluid, transparent, jelly-like body,* 
 
 * Choroid, from the Greek x<^P'oz/, leather, because, being dark-col- 
 ored, it resembles leather in appearance. 
 
 f Ret'ina, a Latin word, meaning in that language just what it 
 means in English. It is derived from re'te, a net, on account of its 
 mesh-like appearance. 
 
 X Vit'reous, from the Latin vit'reus, glassy. 
 
 * The vitreous humor contains, even in healthy eyes, minute bodies, 
 which can not be detected from the outside, but which can be seen, 
 greatly magnified, by the person himself. They are called '■'■ musca 
 volitanfes" {\\texd\\y,JIittingJlies), and look like small strings of bright 
 beads, or little transparent spheres or fibers, which move when the eye 
 is moved, and, when the eye is held perfectly still, seem to sink slowly. 
 They really float up toward the top, but appear to go down, their di- 
 rection being reversed by the optical apparatus of the eye. These little 
 objects are seen most vividly against a bright surface, like the sky, or a 
 white wall, and when perceived for the first time are apt to frighten 
 
SIGHT. 
 
 295 
 
 which fills the ball of the eye, with the exception 
 of a small part, about one sixth of the mass, in front, 
 which contains the crystalline lens and the parts be- 
 tween the lens and the cornea. This vitreous hu- 
 mor is surrounded by a very delicate membrane, 
 also transparent, which lies in immediate contact 
 with the whole extent of the retina. Just where 
 this membrane passes in front of the vitreous hu- 
 mor, and just behind the cornea, it splits in tw^o 
 layers, and between these layers is suspended and 
 held in place the crystalline lens. This lens is a 
 double-convex one, with the posterior curvature a 
 little greater than the anterior, is about one third of 
 an inch in diameter from side to side and a quarter 
 of an inch thick at its middle. It is, of course, per- 
 fectly transparent, and acts precisely as a double- 
 convex lens acts in any optical instrument. Just in 
 front of the lens is a curtain, with a hole in its cen- 
 ter, which serves to regulate the admission of light 
 to the interior of the eye. This curtain is called 
 the i'ris* and it contains muscular fibers, to which 
 it owes its power of contraction, and pigment-cells, 
 to which it owes its color, varying in different per- 
 sons. The hollow space between the cornea in 
 front and the crystalline lens behind is filled bv a 
 fluid called the aqueous hnmor,\ composed almost 
 entirely of water, with a little salt. 
 
 376. Uses of the Two Outer Coats of the Eye. 
 — The sclerotic coat serves, by its toughness and 
 
 people. They exist, however, in every eye, and are perfectly harm- 
 less. 
 
 *'lp(s, a Greek word, meaning the rainbow, so called on account of 
 the variety of colors it presents in different eyes. 
 
 f A'queous, from the Latin a'qucus, wakry, because it consists al- 
 most entirely of water. 
 
296 
 
 ORGANS OF PERCEPTION. 
 
 elasticity, to give shape to the organ, and protect 
 the parts within. The cornea in front answers the 
 same purpose, and is transparent, in order to allow 
 the passage of hght. The 
 choroid coat serves as a 
 nest for the blood-ves- 
 sels which nourish the 
 retina, and also, by its 
 dark color, prevents the 
 rays of light, which have 
 once passed through the 
 retina, from passing back 
 again, and so confusing 
 the sight. When the light 
 which enters the eye is 
 so intense that it can not 
 be absorbed by the cho- 
 roid, it is thus reflected 
 through the retina, and 
 our sight is not clear, as 
 we have a double im- 
 pression, coming from 
 two directions, and the 
 rays conflict with each 
 other. We call this " be- 
 ing dazzled." In albinos, 
 the coloring -matter of 
 the choroid is absent, 
 and such persons always 
 are troubled with dimness and confusion of sight.* 
 
 * Albinos not only can not see well, because they are dazzled by 
 the light, but their eyes have a constant vibratory motion from side to 
 side, like the pendulum of a clock. This peculiar affection is known 
 to physicians as ttystagmus. 
 
 Fig. 67. — Vertical section of the ret- 
 ina, highly magnified. At the 
 upper part of the cut are the rods 
 and cones, while below are several 
 distinct layers of nerve-cells. 
 
SIGHT. 297 
 
 377. The Retina. — The retina is formed by the 
 expansion of the optic nerve, which enters the e3'e 
 behind and spreads out over the interior. It is ex- 
 ceedingly compUcated in its structure (Fig-. 6']'), no 
 less than eight distinct layers being found in its 
 thickness, although the whole taken together is very 
 thin and delicate. The outermost layer is made 
 of innumerable minute cylinders of nervous matter 
 of different shapes and sizes, packed together side 
 by side like the seeds of a sunflower. These are 
 called the rods and cones of the retina. Inside of these 
 are other layers of tubes, fibers, cells, and granular 
 matter, all of which, doubtless, have their part to 
 play, but the particular function of which is not x^t 
 known. This arrangement of the nerve substance is 
 necessary to the sense of sight, for, singularl}^ enough, 
 the spot where the optic nerve enters the eyeball is 
 entirely blind. This nerve can convey the impres- 
 sion of sight to the brain as it receives it from the 
 special sense-organ the retina ; but, if light falls di- 
 rectly upon the optic nerve itself, no sensation is 
 produced. This curious and interesting fact can be 
 easily demonstrated. 
 
 Make a round black spot and a black cross upon 
 a white card, three inches apart (Fig. 6'^. Now 
 
 Fig. 68. — Diagram to demonstrate the existence of the blind spot. 
 
 hold the card in front, at a distance of about a foot 
 trom the eyes, close the left eye, and look at the 
 cross with the right one. Both the cross and the 
 
298 ORGANS OF PERCEPTION. 
 
 black spot will be seen distinctly. Now move the 
 card slowly toward you, still keeping the right eye 
 fixed upon the cross. At a certain point the round 
 spot will disappear, but, as the card continues to 
 approach the eye, it will reappear within the field 
 of vision. At the point of disappearance, its image 
 falls upon the optic nerve just where it enters the 
 eye (Fig. 69). Now, if this blind spot were just in 
 the axis of the eye, we should be badly off, for it is 
 
 Circular image inside the Image on the nerve Image outside the 
 nerve (blind spot). (blind spot). nerve (blind spot). 
 
 Fig. 69. — Diagram illustrating the blind spot. It represents a horizontal 
 section of the right eye, the axis of the eye in every case being turned to- 
 ward the cross. 
 
 evident that we should be unable to see anything 
 we looked directly at. But the point of entrance 
 of the optic nerve is toward the inner side of the 
 eyeball, and consequently we are not incommoded 
 at all by this small spot, which is insensible to light. 
 
 378. Use of the Crystalline Lens. — The interior 
 of the eyeball is, therefore, like the interior of a 
 camera obscura. It forms a dark chamber, lined with 
 a dark membrane, to absorb superfluous light, and 
 with a small opening in front to admit fight. Just 
 behind this opening is the lens. 
 
 If light came directly into the eye, and fell upon 
 the retina, without being brought to a focus, our 
 brains would appreciate the existence of the light, 
 but would not get clear ideas of the appearance of 
 objects. Everything would be dim and confused 
 
SIGHT. 299 
 
 Something of this may be seen in a camera obscura, 
 if the lens be removed. The rays of light, as they 
 enter the camera, still form an image of outside ob- 
 jects, but it is a dull, indistinct, and obscure one. 
 With the lens, however, the picture is bright and 
 distinct in all its details. The reasons for this are 
 too long to be stated here, and will be found in any 
 treatise on optics. Suffice it to say that the func- 
 tion of the crystalline lens is to concentrate the rays 
 of light as they enter the eye, and bring them to a 
 focus on the retina. 
 
 379. The Function of Accommodation. — The 
 rays of hght being affected by this lens precisely as 
 they would be by a glass one, there must be some 
 provision made for the varying distance of objects 
 from the eye. In the camera, as objects are nearer 
 or more distant, Ave draw out or push in the lens, 
 so as to bring it farther from or nearer to the sur- 
 face which receives the image. Now, we find that, 
 within certain limits, a healthy eye sees objects a 
 moderate distance away with just as much distinct- 
 ness as those near at hand. jNloreover, we are con- 
 scious, as we change rapidly from looking at a dis- 
 tant object to one close by, of a kind of effort in the 
 eye itself. There must be a change of some kind 
 there, corresponding to the pulling out or pushing 
 in of the lens of the camera. What is the change ? 
 
 There is a short, delicate muscle, called the cili- 
 ary muscle, one extremity of which is attached to 
 the stout membrane of the sclerotic and cornea at 
 their junction, and the other extremity to the cho- 
 roid. The muscle is a circular one, reaching all 
 around the eyeball, and is only about an eighth of 
 an inch broad. Now, the crystalline lens is verj 
 
300 
 
 ORGANS OF PERCEPTION 
 
 elastic, and, as has been stated, it lies between two 
 layers of a membrane which passes backward and 
 surrounds the vitreous humor. Under ordinary 
 circumstances, these two layers of membrane, one 
 of which is in front of the lens and the other be- 
 hind it, are supposed to exercise some pressure on 
 it, and render it a little flatter than it would be, if it 
 were left to take its own shape, in accordance with 
 its elasticity. Now, suppose that we wish to look 
 at an object close at hand. The ciliary muscle con- 
 tracts and the membranes surrounding the vitreous 
 humor are drawn forward slightly. As a conse- 
 quence of this the two layers of membrane, between 
 which the lens lies, are somewhat relaxed, and exert 
 less pressure on the front and back of the lens. The 
 pressure being removed from it, the 
 elasticity of the lens makes it assume 
 a more convex shape (Fig. yd), and 
 consequently brings the rays of light 
 to their proper focus. This is sup- 
 posed to be the method by which 
 the eye accommodates itself to differ- 
 ent distances, and its operation is so 
 perfect and exact that, within certain 
 limits, we can see whatever we wish 
 to. Beyond a certain distance, and 
 within a certain distance, this accom- 
 modation no longer occurs. These 
 distances vary with different per- 
 sons, and the inner limit is called the liinit of dis- 
 tinct vision. 
 
 380. The Limit of Distinct Vision. — The limit of 
 distinct vision depends on the accommodation of 
 the lens above described. As any object is brought 
 
 Fig. 70. — Diagram 
 showing how the 
 lens changes its 
 form for near and 
 far sight. 
 
SIGHT. 301 
 
 nearer and nearer to the eye, the effort required to 
 see it distinctly, or, in other words, the effort at ac- 
 commodation, is greater and greater, until at length 
 it begins to be accompanied by pain and a pecuHar 
 sense of fatigue in the eyes. Within this point dis- 
 tinct vision is not possible, for the ciliary muscle 
 can contract no further. In healthy eyes, this limit 
 is usually about six inches from the cornea. 
 
 As objects recede, the rays from them come to 
 the eye at a smaller and smaller angle, until, at 
 the distance of fifty feet, they are almost parallel ; 
 that is, they are practically so, as far as the percep- 
 tion of the retina is concerned. Beyond this point, 
 vision is distinct enough, and no accommodation of 
 the lens is required ; but a new difficulty comes in 
 to hamper us in our perception of objects. We 
 have seen that, however delicate the sense of touch 
 may be, it is possible to press two points of a com- 
 pass on the skin so near together that we are not 
 able by the sense of touch to say whether they are 
 two points or one. A similar condition is found to 
 exist in the retina. It has been shown by experi- 
 ment that, if two objects or two points of any ob- 
 ject are so near together that both combined sub- 
 tend an angle of less than one minute at the lens, 
 the retina can not distinguish them apart. Beyond 
 the distance of fifty feet, then, without artificial as- 
 sistance, the eye is unable to distinguish objects 
 perfectly in their minute details. 
 
 381. The Function of the Iris. — The color of 
 the iris is due partly to the blood-vessels which run 
 through it, and partly to small pigment-cells. In 
 new-born children the iris is always blue, and does 
 not take on the color which is to last through life 
 
302 
 
 ORGANS OF PERCEPTION. 
 
 for several weeks after birth. The iris performs 
 two functions. In the first place, in every lens, the 
 whole of which is made of the same substance and 
 of the same density throughout, the rays of hght 
 which pass through and near the center are not 
 brought to a focus as soon as those which pass 
 through near the circumference. This fact causes 
 a blurring of the image (spherical aberration) and 
 also a partial decomposition of the light (chromatic 
 aberration), so that the image appears colored at 
 its edges. In optical instruments these difficulties 
 are remedied, partly by constructing the lens of two 
 different substances, which counteract each other's 
 defects, and partly by covering the edge of the lens 
 and only allowing the light to come through the 
 center and the immediately adjacent parts. The 
 latter method is the one carried out by the iris. It 
 is pierced in the center, forming the pupil of the 
 eye, and this pupil is situated immediately in front 
 of the center of the lens, so that in this way the 
 faults above mentioned are corrected. The iris 
 also regulates the admission of light to the eye. 
 Too much light irritates the retina, and by reflex 
 action the iris contracts. If there be loo little light 
 the iris is relaxed, and the pupil becomes larger so 
 as to admit more. This process has already been 
 mentioned at length. 
 
 382. The Retina and Optic Nerve sensitive only 
 to Light. — The retina is sensitive to other impulses 
 than that of light, but, whatever these impulses 
 may be, the sensation of light is the only one con- 
 veyed to the brain. If the eyeball be struck or 
 pressed, or an electrical current be passed through 
 it, we see sparks or flashes of light, and this even 
 
SIGHT. 303 
 
 when we are in a perfectly dark room. This is due 
 to the shock to the retina, from which every stimu- 
 lus of whatever kind is transmitted by the optic 
 nerve to the brain under the form of light. 
 
 383. Persistence of Impressions on the Retina. 
 — When an image is formed on the retina, espe- 
 cially if it is a very bright one, the impression re- 
 mains a little while after the object that caused it 
 has passed by. The consequence of this is that, if 
 several objects follow each other in very rapid suc- 
 cession, new images are continually formed on the 
 retina before those that immediately preceded them 
 have had time to fade, and so the eye does not de- 
 tect any interval between them. Thus, when we 
 look at a swiftly-revolving w^heel, we do not see the 
 separate spokes, but a continuous, hazy blur; and 
 when a live coal is whirled around fast enough be- 
 fore the e3'es, we do not see the coal in its proper 
 shape, but only a luminous circle. In this tempo- 
 rary persistence of impressions on the sense of 
 sight, it is like all the other senses. 
 
 384. Color-Blindness. — The power of discrimi- 
 nating between different colors varies very much in 
 different individuals. While some can not only dis- 
 tinguish the colors with ease, but can pick out the 
 most delicate shades of any particular color with 
 unfailing accuracy, others are unable to discrimi- 
 nate, for example, between red and green. Such 
 persons are called color-blind, and can not see any 
 difference between the fruit and the leaves of a 
 cherry-tree, excepting by the shape. 
 
 385. Near-Sight and Far-Sight. — In the natural 
 and healthy eye the ravs of light are brought to 
 a focus on the retina, but in some eyes they are 
 
304 ORGANS OF PERCEPTION. 
 
 not. In near-sighted persons the eyeball is usually 
 a little too long, and the rays of light, being brought 
 to a focus before they reach the retina, cross each 
 other, and the image is blurred. In far-sighted 
 eyes the eyeball is too short, or the lens is too flat, 
 and the rays are not brought to a focus at all, so 
 that the effect upon vision is to make everything 
 look blurred, as in the former case (Fig. 71). Both 
 of these defects can and should be corrected by 
 proper glasses, for the constant straining to see, of 
 
 Fig. 71. — Diagram showing- the point at which the rays of hght are brought 
 to a focus in different eyes. 
 
 short-sighted and far-sighted persons who try to get 
 along without glasses, eventually injures the sight. 
 386. Muscles of the Eyeball. — To the outside of 
 the eyeball are attached six muscles, by means of 
 which it can be moved in any direction. Four of 
 them pass from the four sides of the eyeball straight 
 backward to the bone at the rear of the orbit, and 
 move the eye up or down, and to the right or left. 
 The other muscles are attached, one to the upper 
 and the other to the lower surface of the eye-ball, 
 their other ends being attached to the bones on the 
 inner side of the orbit in such a way that, by their 
 contraction, the eyeball is rolled in one direction or 
 another. 
 
SIGHT. 305 
 
 387. The Eyelids and Eyebrows. — This delicate 
 organ — the eye — is protected from injury in front 
 by a number of accessory parts, viz., the eyelids^ eye- 
 lashes, and eyebrows. 
 
 The eyelids are composed of thin pieces of car- 
 tilage, covered with skin on the outer and lined 
 with mucous membrane on the inner side. They 
 are movable, and, when open, expose nearly all the 
 iris ; when shut, they completely cover the eyeball. 
 At their margins are several short, stiff hairs — the 
 eyelashes — which project outward and downward, 
 and serve as an additional protection against the 
 entrance of dust and insects. Above the ej-es are 
 ridges of thick skin, also covered with hairs, and 
 called the eyebrozvs, which turn aside the perspira- 
 tion or other fluids which run down the forehead 
 toward the eyes. 
 
 388. The Tears. — In order to keep the cornea 
 perfectly smooth and transparent, and to preserve 
 the softness of the mucous membrane lining the in- 
 terior of the lids, which continually sweep over the 
 cornea, and if rough would irritate and ruin it, a 
 special fluid is provided, called the tears, which are 
 continually secreted, and keep those parts constant- 
 ly moist. The gland which provides the tears, 
 called the lach'ryinal gland {Fig. ^2), is situated inside 
 the orbit, just above and outside of the eyeball, and 
 its secretion is poured out on the eve by several 
 little openings at the upper part of the upper lid, 
 on its inner surface. By the winking of the lids, 
 which occurs frequently and is usually involuntarv, 
 it is spread over the surface of the eve. On the 
 edge of the lids, near the inner angle of the eye, 
 may be seen two minute openings, one in each lid. 
 
3o6 
 
 ORGANS OF PERCEPTION. 
 
 These are the mouths of two little canals, which 
 pass from these points toward the nose, soon unit- 
 
 FiG, 72. — Left eyelids from behind. Above and at the left is the lachrymal 
 gland. On the lids are seen what look like strings of beads. They are 
 glands that secrete the fatty matter that coats the edges of the lids, and 
 keeps the tears from running over. 
 
 ing in one larger canal, which runs downward into 
 the nasal cavity. Through these minute canals, the 
 superfluous tears run off into the nose. These 
 canals are lined with mucous membrane, and, dur- 
 ing a cold in the head, the inflammation often closes 
 them, and the tears, not finding free passage through 
 them, overflow upon the cheeks. This overflow 
 also occurs when from pain or any powerful emo- 
 tion the tears are increased in amount so that the 
 canals are unable to dispose of the extra supply. 
 This phenomenon we call crying or %veeping. An 
 overflow of tears is guarded against under ordinary 
 circumstances by an oily secretion of certain glands 
 in the lids, which is discharged just along their 
 edges. This secretion keeps the lids from sticking 
 together when closed, and also retains the tears, un- 
 less their quantity is greater than common. 
 
SIGHT. 307 
 
 389. Effect of Alcohol and Tobacco on the Eyes. 
 — When alcohol and tobacco are used habitually, 
 dimness of vision sometimes results, beginning with 
 a slight obscuration, as if there were a fog before 
 the eyes, and gradually progressing, without pain 
 or any signs of inflammation, to total blindness. If 
 the bad habit is abandoned w'hen the first symp- 
 toms appear recovery is almost certain. At this 
 period of the disease there is simplj^ some conges- 
 tion of the optic nerve. But if the warning is un- 
 heeded and the drinking or smoking is continued, 
 the nerve begins to waste, and atrophy is the re- 
 sult. This produces incurable blindness. Some 
 careful observers state that this disease, when pro- 
 duced by tobacco, presents peculiar features, which 
 point out its cause, and it has been called " tobacco- 
 amaurosis." This seems to be the only organ of 
 the body in which it is yet positively known that 
 tobacco causes permanent degeneration. 
 
 390. Care of the Eyes. — It is exceedingly impor- 
 tant that proper care should be taken of the eyes. 
 They are very delicate, and yet there is hardly an 
 organ in the whole body, not even excepting the 
 stomach, that is more frequently abused. If any- 
 thing be the matter with the eyes — if they smart, or 
 tingle, or itch, or the sight is dim, or blurred, or in- 
 distinct — a good oculist should immediately be con- 
 sulted. More is known about the eye, probably, 
 than about anv other oro;"an in the bodv. The most 
 eminent scientists in the world have spent their best 
 years in the study of it in health and disease, and 
 it can be examined inside and outside thoroughly. 
 As a consequence, operators who devote their spe- 
 cial attention to this organ generally know what 
 
308 ORGANS OF PERCEPTION. 
 
 they are about, and their advice should be carefully 
 and minutely heeded. It will not do for individuals 
 to treat their own eyes, and therefore it is unneces- 
 sary to say anything about its disorders. With re- 
 gard to proper care of the eye, it is almost enough 
 to say. Do not do anything to produce a feeling of 
 *' strain " in the organ. This sensation, as already 
 explained, is produced by the effort of accommoda- 
 tion, and, as the muscular contraction accompany- 
 ing this act compresses the interior of the eye some- 
 what, it causes a congestion of the blood-vessels, 
 which is usually only temporary, and passes away 
 when the cause is removed. If a strain like this, 
 however, be often repeated or long continued, it is 
 apt to result in permanent injury to the sight, just 
 as long-continued congestion of the blood-vessels in 
 any other part of the body will impair the working 
 of the organ in which it occurs. The same effect 
 is produced by reading or using the eyes for fine 
 work while stooping or lying, or during the inces- 
 sant jarring .of a vehicle, especially a railroad-car. 
 The eyes should not be rubbed, or pressed, or 
 squeezed; or used by a bad light, or in any other 
 way treated as if they could bear rough usage.* 
 They can not, and, if they are abused, the sight is 
 apt to fail in a sudden and alarming manner. 
 
 * It is supposed by many that the eyes are strengthened by being 
 opened in cold water when the face is washed. This is not so. On 
 the contrary, it is an exceedingly injurious practice, and frequently 
 produces little ulcers on the surface of the eye, which, although per- 
 haps not dangerous, are very painful, and may prevent the use of the 
 affected eye for several days. The eyeball is washed sufficiently by 
 the tears. 
 
PART VII. 
 
 ORGAN OF SPEECH. 
 
 391. Structure of the Larynx. — In the upper part 
 of the neck, in front, is a hard, projecting mass, 
 which, in the throats of thin persons, is plainly vis- 
 ible, and in every one can be easily felt. This is 
 commonly called Adanis apple, and consists of the 
 projecting cartilages which form the sides of the 
 larynx. This organ is situated at the upper end of 
 the trachea, and a cross-section of it is nearly trian- 
 gular in shape. It is composed mainly of cartilage, 
 and forms a stiff, open, box-like organ, covered on 
 the outside with muscles, and on the inside with 
 mucous membrane. 
 
 392. The Vocal Chords. — The upper end of the 
 larynx is nearly closed by muscular and membra- 
 nous tissues, which divide it at this point from the 
 throat. But it has a chink-like opening, the glottis, 
 previously described, situated at the base of the 
 tongue, just behind the epiglottis. This is the es- 
 sential organ of voice. All the air which passes 
 into or out of the lungs must go through the glot- 
 tis. Now, in front, the vocal chords, which form the 
 
 21 
 
3IO ORGAN OF SPEECH, 
 
 sides of the glottis, are nearly or quite in contact, 
 while the posterior extremities can be separated to 
 quite a distance from each other. These posterior 
 ends are attached to two small cartilages, which can 
 be rotated by certain muscles, so as to separate the 
 vocal chords. When certain other muscles contract, 
 which act in an opposite direction, the cartilages are 
 rotated inward, and the vocal chords are brought 
 nearer together.^ Other muscles render the chords 
 tighter or looser, according to circumstances (Fig. 
 
 73)- 
 
 393. How the Voice is produced. — Now, when 
 
 High note. Medium note. Low note. 
 
 Fig. 73, — The vocal chords in different positions. The opening between the 
 
 chords is the glottis. 
 
 the air is forced through the glottis in expiration 
 with sufficient rapidity, the vocal chords are thrown 
 into vibration, and, vibrations being thus caused in 
 the column of air in contact with them, sound is 
 produced. The quality of this sound, as well as its 
 pitch and tone, depends upon well-known physical 
 laws. The farther apart and the more relaxed the 
 vocal chords are, the lower will be the sound ; the 
 
 * These cartilages are triangular in shape, and act very much like 
 the triangular pieces of metal to which bell-wires are fastened. The 
 vocal chord being attached to one corner, and the muscle to another, 
 while it rotates about the third angle, it is evident that when one muscle 
 contracts the vocal chord will be moved outward, and when another op- 
 posing muscle contracts the end of the chord will be moved inward. 
 
ORGAN OF SPEECH. 
 
 311 
 
 nearer together and tighter drawn they are, the 
 more acute will be the sound. Differences also de- 
 pend upon the size of the larynx and trachea, the 
 length of the vocal chords, their thickness and 
 smoothness, the condition of the throat and parts 
 adjacent, etc. 
 
 In this way the sound is made which we call 
 1)oice, and it is modulated into articulate speech 
 by the action, separate or combined, of the throat, 
 nose, palate, tongue, teeth, and lips. To consider 
 bow these variations are produced would require 
 great space, and be foreign to the purpose of this 
 book. It is sufficient to say that the voice is pro- 
 duced in the larynx, and articulation performed by 
 the parts above that organ. 
 
 394. Abuse of the Larynx. — Abuse of the larynx 
 produces bad results, as does abuse of any other or- 
 gan of the body. Perhaps the most common form 
 of this is the use of the voice, when the vocal chords 
 are in an inflamed or congested condition. Over- 
 use of the larynx in speaking is apt in many persons 
 to bring on congestion of the chords. This causes 
 them to swell a little, and the voice loses some of 
 its clearness. If rest be not given the organ at 
 such a time, the congestion continues, and becomes 
 chronic. Then the voice is permanently altered, 
 becoming rough and harsh as compared with its 
 original quality. Very often a sore-throat extends 
 to the glottis, and the mucous membrane which 
 covers the vocal chords becomes inflamed. Then 
 the usual results of inflammation of a mucous mem- 
 brane follow. The chords swell and are covered 
 with a thick secretion, like that Avhich is coughed 
 up during such an attack. This thickening of the 
 
312 
 
 ORGAN OF SPEECH. 
 
 chords affects the voice, and makes it not only 
 harsh but of a lower note than usual, just as in a 
 violin the large strings give forth the low notes 
 and the smaller ones the high notes. The secretion 
 also hinders the vibration of the chords, and some- 
 times the voice is reduced to a whisper or even ex- 
 tinguished, because the chords are so disabled as 
 not to be able to vibrate at all. A curious phenom- 
 enon sometimes occurs in such cases, called the 
 ''breaking of the voice." If the mucous secretion 
 be very viscid, as it often is, the chords may stick 
 together at some point during the act of speaking, 
 and the part that vibrates is instantly reduced in 
 length to perhaps three quarters of what it was a 
 moment before. This has the same effect as the 
 shortening of a string of a violin by pressing it 
 with the finger. It makes the voice suddenly take 
 on a higher note. In the next instant the chords 
 become entirely separated, and the former note re- 
 turns, and so the speech consists of a singular series 
 of growls and squeaks. 
 
 395. Care of the Larynx. — When the chords are 
 in this condition they ought to be used as little as 
 possible, or permanent injury to the voice will be 
 apt to result. It must be remembered that the mu- 
 cous membrane of the larynx in such cases is dis- 
 eased and sore, and ought not to be rasped by a 
 forcible current of air, or it will not readily recover. 
 If one has a sore spot on his hand, he does not rub 
 it violently several times a day ; he lets it rest until 
 it is well again. In such a case, the pain which re- 
 sults from rough treatment is a sufficient indication 
 of its harmfulness, but inflamed or congested vocal 
 chords are not usually painful, and the use of the 
 
ORGAN OF SPEECH. 
 
 313 
 
 voice is so necessary a part of our daily life that 
 every one is too apt to neglect warnings regarding 
 it. But Nature is inexorable, and shows no favor. 
 Her penalties are severe and unerring. 
 
TABLE OF THE BONES. 
 
 Skull 
 
 Cranium 
 (brain-case) : 
 
 Face : 
 
 Occipital (back of head) „ 
 
 2 Parietal (sides of head, above) 
 
 2 Temporal ( sides of head, below). , . 
 
 Frontal ( forehead) 
 
 Sphenoid (at base of skuU) 
 
 Ethmoid (base of skull, over nose), . . 
 
 2 Superior maxillary (upper jaw) . . . . 
 
 Inferior maxillary (lower jaw) 
 
 2 Malar (cheek-bones) 
 
 2 Lachrymal (part of the orbit) 
 
 2 Nasal (bridge of nose) 
 
 2 Inferior turbinated (inside of nose). 
 
 2 Palatal (at back of nose) 
 
 Vomer (part of partition of nose)... . 
 
 23 
 
 14 
 
 Spine 
 
 (back-bone) 
 
 A 
 
 Os HYOIDES (hyoid bone, at base of tongue) 
 
 Cervical vertebrae i f^^^ (°^^^ *« ^^^")- 
 (in the neck): "j ^^-[[[[[[[[[^ 
 
 Dorsal vertebrae (supporting the ribs) 
 
 Lumbar vertebra (in small of back, or loins) . 
 Sacrum j (These bones, together with the ) 
 Coccyx I hip-bones, form the pelvis.^ \ 
 
 Ribs (12 on each side) 
 
 Sternum (breast-bone) 
 
 12 )■ 
 
 5 
 
 I 
 
 26 
 
 24 
 
 '' Clavicle (collar-bone) . . . . 
 Scapula (shoulder-blade) 
 Humerus (upper arm) . . . 
 
 Upper 
 Limbs: 
 
 Radius } ,c \ 
 
 Ulna \ (forearm) 
 
 I 
 I 
 
 Scaphoid, semilunar, cuneiform, 
 pisiform, trapezium, trapezoid, 
 OS magnum, unciform 
 
 Metacarpal bones (hand) 
 
 Phalanges (thumb, 2 ; fingers, 3 each ) 
 
 Carpal bones * 
 (wrist) : 
 
 
 64 
 
 Lower 
 Limbs : 
 
 Os innominatum (hip-bone) 
 
 Femur (thigh-bone) 
 
 Tibia (shin-bone) ) ,, ^ 
 
 Fibula. \ ^^^Z) 
 
 Patella (knee-pan) 
 
 ( Calcaneum or os calcis (heel-bone). 
 Tarsal bones] astragalus, cuboid, scaphoid, in- 
 (ankle) : 1 ternal, middle, and external c6- j 
 
 [ neiform J 
 
 Metatarsal bones (foot ) 
 
 Phalanges (great toe, 2 ; other toes, 3 each) 
 
 5 
 14 J 
 
 1 
 I 
 
 2 
 
 I 
 
 5 
 14 ; 
 
 
 62 
 
 fO 
 
 Total + 200 
 
 * Beginning at thumb-side of wrist in each row. 
 
 t The- minute bones of the ear, 3 on each side, are sometimes included in the list 
 of bones, making 206. The teeth (20 temporary and 32 permanent) are not bones. 
 
QUESTIONS. 
 
 PART I. 
 
 Chapter I. — i. What is anatomy ? Physiolog\-? Hygiene? ^^^^at 
 is an anatomical element ? A tissue ? An organ ? A system ? An 
 apparatus? Give examples of each. What is the function of an or- 
 gan ? What is a poison ? A stimulant ? A narcotic ? A narcotic poi- 
 son ? What is opium? Morphia? Laudanum? Paregoric? How 
 is alcohol produced ? Its properties? Its composition ? Is it always 
 an artificial product ? Tobacco ? Its most important ingredient ? 
 Properties of nicotine? What is chloroform ? Chloral? 
 
 Chapter II. — 2. What is the minute structure of the body ? Which 
 is the original element ? What causes the different consistency of dif- 
 ferent organs? 3. What is a fiber? Where found? 4. Why is the 
 cell so important ? What is a cell? Nucleus? Nucleolus? 5. What 
 is protoplasm? How large are cells? 6. What other kind of matter 
 exists in the body ? 7. What is the difference between living and dead 
 cells ? Illustration ? 8. How do cells increase in number ? 9. What 
 other powers do cells possess ? How are wounds healed ? What is 
 said of ''proud flesh " (foot-note)? Does one cell ever perform the 
 duty of another? Give example (foot-note). 10. How does alcohol 
 affect growing cells ? 
 
 PART II. 
 
 Chapter I. — 11. Why are bones necessary? 12. How does living 
 bone differ from dead bone? 13. What is the composition of bone? 
 What experiments will show this ? 14. How are bones affected by 
 age? W^hat is a "green-stick" fracture? 15. How many kinds of 
 bones are there ? What is the structure of the shaft ? Of the extrem- 
 ities? Why the difference ? What is the marrow? 16. What is the 
 periosteum ? What is the minute structure of bone? 17. What is the 
 use of the periosteum? Illustrate. 
 
 Chapter II. — 18. How many bones in the body? What is ossifi- 
 cation? When complete? 19. What is the spine ? What is a vertebra? 
 How are the vertebrae arranged in the spine? What separates them? 
 How is the spinal canal formed, and what does it contain ? 20. How 
 
3i6 QUESTIONS. 
 
 movable is the spine ? How is it held together? What is the use of 
 the pads between the vertebra ? Is a man taller in the morning or at 
 night? Why? 21. What is the skull ? How are its bones peculiar? 
 What is the advantage of its arched shape ? What movable bone in 
 the skull? 22. What are the sutures of the skull? What is their 
 use ? 23. What are the frontal sinuses ? How may they cause head- 
 ache? 24. Describe the ribs. How many are there? How are they 
 attached to the breastbone ? What are the floating ribs ? How does 
 the motion of the ribs alter the form of the chest? 25. How do the 
 cartilages of the ribs change with age? How does pressure affect 
 them ? What is the natural shape of the chest ? 26. How many bones 
 are there in the limbs? What is meant by homologous bones? 27. 
 How are joints formed? What is cartilage? Synovial membrane? 
 Ligaments ? Uses of these parts. 
 
 Chapter III. — 28. What is a fracture? A dislocation? How can 
 they be told apart? 29. How are bones generally broken, and why 
 does the limb generally become shorter after a fracture ? Why is a 
 fracture near a joint so serious? 30. Why is a dislocation so painful? 
 In what joints are dislocations most common ? How are they generally 
 caused? What is a sprain (foot-note)? 31. How long does it take a 
 broken bone to unite? 32. How should a broken limb be cared for 
 before the doctor comes ? How can the patient be carried ? 33. How 
 does alcohol affect growth? 34. Effect of tobacco on development? 
 35. Effect of opium on children ? 
 
 Chapter IV. — 36. How are the bones moved ? W^hat two kinds 
 of muscle are there? 37. What is a voluntary muscle? What is con- 
 nective tissue (foot-note) ? Use of muscle. How does voluntary mus- 
 cular fiber look under the microscope ? What is striation ? 38. What 
 is the minute structure of involuntary muscular fiber? 39. How do 
 voluntary and involuntary muscles differ in their action ? Peculiarity 
 of the heart-muscle. Where are involuntary muscles found ? 40. Do 
 muscles vary much in size? Illustrate. 41. How are the muscles con- 
 nected with the bones? What is a tendon? Describe the peculiar 
 arrangement of tendons at the wrist and ankle. 42. Describe the dis- 
 advantages under which a muscle exerts its force during contraction. 
 43. What is the irritability of muscle ? Give illustrations. 44. What is 
 meant by the muscular sense? Of what use is this sense? 45. Illus- 
 trate the use of this sense in standing. 46. What is the effect of con- 
 traction on the muscle itself? 47. What is the effect of muscular over- 
 work? 48. What is the result of muscular inactivity? Give illustra- 
 tions. Hov/ is curvature of the spine produced (foot-note)? 49. What 
 IS the best exercise ? What is said of gymnastic training? 50. W^by is 
 
QUESTIONS. 317 
 
 exhaustion dangerous? 51. Why is rest necessary? What simple rules 
 for exercise are given? 52. What permanent changes does alcohol 
 tend to produce in the body? 53. How does it affect the muscles? 
 54. How does it affect the power of endurance? 
 
 PART III. 
 
 Chapter I. — 55. Why do we need food? 56. Can people live 
 without eating? Why? 57. What are the two great divisions of foods? 
 58. What proportion of the body is water? How much water is need- 
 ed daily? 5g. Illustrate the importance of salt (foot-note). 60. What 
 other inorganic substances are taken in food ? Why is lime so impor- 
 tant? 61. What are the non-nitrogenous foods? 62. In what foods is 
 starch found? What peculiarity has starch? 63. In what foods is 
 sugar found ? Name some of the varieties of sugar. What is said of 
 glucose (foot-note) ? 64. What is the use of fat in the body ? Is the 
 fat all taken into the body with the food? What articles of food tend 
 to produce fat? Illustrate. Describe ]Mr. Banting's case (foot-note). 
 65, What are nitrogeneous foods? What other name are they known 
 by to physiologists? In what foods are the nitrogenous substances 
 found ? Are similar substances found in vegetable foods ? 66. Why 
 do we need variety in our food ? 67. Which is the most essential of all 
 articles of food or drink? Illustrate. 68. How much of each kind of 
 food is needed daily? 69. What is the eft'ect of cooking upon food? 
 
 Chapter II. — 70. What is fermentation? Its cause? 71. Men- 
 tion some of the different kinds of fermentation. Describe vinous 
 fermentation. What are its chief products? Describe acetous fer- 
 mentation (foot-note). Is alcohol a food ? 72. What are alcoholic 
 beverages made of? 73. How are malt liquors manufactured? 74. 
 What are the principal malt liquors, and; how do they differ? 75. 
 What peculiar and dangerous quality has alcohol, in common with 
 other narcotic poisons ? What is the only absolute safeguard against 
 it? 76. How are domestic beers made? Are they harmless drinks? 
 77. How are wines manufactured ? Describe the micro-organisms 
 that start the fermentation. How are they introduced into the grape- 
 juice ? How is the fermentation arrested ? What is cider ? Does it 
 contain alcohol ? 78. What is perry ? Koumyss ? 79. What is the 
 usual cause of effervescence ? Is it always the result of fermentation ? 
 80. What tendency has the habitual use of " light liquors " ? Illustrate 
 (foot-note). 81. W^hat is the principle of distillation ? Describe the 
 process. What is " the worm of the still " ? 82. What are the prin- 
 cipal distilled liquors? How do they differ? What is their alcoholic 
 
31 8 QUESTIONS. 
 
 strength ? What imparts to them their peculiar flavor and odor? 83. 
 What is the dangerous ingredient of all these drinks ? Is alcohol 
 decomposed by distillation ? 
 
 Chapter III, — 84. W^hat is the use of the digestive apparatus ? 
 85. What are the five stages in the preparation of food for the needs of 
 the body ? 86. Which of these stages is under control of the will ? 
 Why must all the stages be properly carried through ? 87. Use of the 
 senses of taste and smell. 88. Use of the teeth. Of the cheeks and 
 tongue. What is the masseter muscle ? What is said of the sound 
 accompanying muscular contraction ? 89. What is the saliva ? What 
 are the parotid glands ? How does their secretion differ from that of 
 the other salivary glands ? Does the secretion of saliva vary in amount 
 at different times ? Illustrate (foot-note). 90. What are the properties 
 of the saliva? Its effect upon starch? Its use in the preparation of 
 food. Illustrate. How much saliva is secreted daily ? What is said 
 of the care of the teeth (note) ? 
 
 Chapter IV. — 91. What is the alimentary canal ? 92. What is 
 mucous membrane ? Its minute structure ? What are epithelial and 
 epidermal cells (foot-note) ? 93. Describe the character and arrange- 
 ment of the muscles in the alimentary canal. What is the result of 
 their contraction? 94. What is serous membrane? Its use? 95. 
 What are the pharynx and oesophagus ? How do we swallow ? 96. 
 How large is the stomach ? What is its shape ? Where are its two 
 openings, and what ?re they called ? What is the great pouch of the 
 stomach? In what direction do substances pass through the stomach, 
 and how is this regulated ? 97. What portions of the food are digested 
 in the stomach ? 98. Describe the accident to St. Martin, and its re- 
 sult. 99. What is the appearance of the interior of a healthy stomach ? 
 100. How does the gastric juice appear during secretion ? When is it 
 secreted ? loi. What two necessary ingredients has the gastric juice ? 
 Can food be digested outside of the body ? How much gastric juice is 
 secreted daily? 102. What part do the muscles of the stomach perform 
 during digestion ? 103. What is the appearance of the interior of the 
 stomach during indigestion ? Is the gastric juice secreted at such times ? 
 How is the tongue affected? 104. How long a time is required for 
 stomach-digestion ? 105. How does thorough mastication assist diges- 
 tion, and why ? 106. What is said of eating too little ? 107. Why is it 
 harmful to eat too much? 108. Why should we not eat between meals? 
 109. What is hunger ? Why is plain food the best ? no. How are we 
 to know when we have eaten enough? How far apart should our 
 meals be? in. How are we to judge of what to eat? 112. What is 
 said of pepper and mustard? What is the golden rule about eating? 
 
QUESTIONS. 319 
 
 113. What is the natural drink? 114. What are the effects of tea and 
 coffee? 115. What are the effects of pure alcohol upon the stomach? 
 116. Of diluted alcohol? Does it interfere with digestion? 117. 
 Effect of an intoxicating dose of alcohol upon the stomach? 118, 
 What serious changes may be brought about in the stomach by alco- 
 hol ? 119. Effect of opium on the stomach? Of morphia? What 
 bad effect may follow the injection of morphia under the skin (foot- 
 note)? 120. What are the effects of tobacco due to? How much 
 nicotine in a cigar? 121. What is the effect of tobacco when first 
 used? 122. Effect of tobacco on digestion? How does the use of 
 tobacco lead to the use of alcohol? 123. Is opium a food? How 
 does it sometimes seem to act as a food? 124. How is candy adul- 
 terated ? What kinds are to be avoided ? Why ? 125. What is the 
 trichina spiralis ? The cysticercus cellulosoe ? How can they be killed ? 
 What advantage in boiling drinking-water? What are the general 
 rules about eating ? 
 
 Chapter V. — 126. What becomes of the fats, sugars, and starches 
 in the stomach? What is the chyme? 127. What is the structure of 
 the small intestine ? How does it join the large intestine ? What is 
 the course of the latter? What is the appendix vermiformis (foot-note)? 
 128. How do the muscular fibers of the intestine contract ? What is 
 the result ? 129. What is the duodenum ? 130. What is the pancreas? 
 What is its use? 131. What is the liver? Its secretion? ^2. What 
 other function has the liver? 133. What is the bile? Where is it 
 discharged into the intestine ? What reason is there for supposing that 
 it is an excrementitious fluid ? What is jaundice ? What is the result 
 if the bile is prevented from entering the intestine ? Illustrate. Does 
 the bile leave the body? What is the inference from these facts? 134. 
 What are the intestinal juices? How are they useful? 135. How is 
 it shown that food is absorbed from the intestine ? What vessels absorb 
 it? Origin of the name lacteal (foot-note)? 136. What is the peri- 
 tonaeum ? Its use ? How do the blood-vessels and lacteals get to the 
 intestine ? Where do they terminate ? 137. What are the villi ? 
 Their size, number, and structure ? 138. What are the lymphatics ? 
 The lymph ? The lymphatic glands ? What is the function of the 
 lymphatics ? What are the lacteals ? The thoracic duct ? 139. Where 
 is the blood from the intestines carried ? 140. What is the function 
 of the villi ? What is the chyle ? How is it absorbed (foot-note) ? 141. 
 Describe the changes in the blood during digestion. 142. What is the 
 effect of alcohol upon the liver? How is cirrhosis produced? 143. 
 What are the general effects of alcohol upon nutrition ? Of tobacco? 
 144. What is the spleen ? Why would it seem to be an important or- 
 
320 QUESTIONS. 
 
 gan ? What is the result of its removal ? What is probably its function 
 (foot-note) ? 
 
 Chapter VI. — 145. What is the blood? Its physical properties ? 
 146. What are the red blood-corpuscles? Their appearance and size? 
 How do they differ in different animals? 147. What are the white 
 blood-corpuscles ? How numerous are they ? What is their appear- 
 ance and size ? How much of the blood is made up of corpuscles ? 
 148. What is the plasma ? Its composition ? 149. What is coagula- 
 tion? What is the clot? The serum? Why is the clot red? How 
 does serum differ from plasma? 150. What conditions affect the 
 rapidity of coagulation? Will blood coagulate inside of the body? 
 Illustrate. 151. What is the total amount of blood in the human 
 body? 152. What gas is absorbed by the blood from the air? How 
 important is it to life ? Illustrate. 153. What process causes the 
 blood to change color? 154. Effect of alcohol on the blood? Of 
 tobacco ? 
 
 Chapter VII. — 155. Is respiration a simple process ? 156, What 
 is the structure of the interior of the nose ? Why is it better to breathe 
 through the nose than through the mouth? 157. What is the trachea? 
 What are the bronchi? How are these tubes kept open? Do the 
 rings of the trachea entirely surround it ? Why not ? What is the 
 larynx? 158. What is the glottis ? Where is it situated ? What are 
 the vocal*chords ? What is the epiglottis? Its use ? I5g. What are 
 the lungs, their situation, appearance, and weight ? 160. What is the 
 minute structure of the lungs ? What is a pulmonary lobule ? A pul- 
 monary vesicle? Their si^e? 161. What peculiarity has the lining 
 membrane of the lungs ? W^hat is the function of the cilia ? 162. 
 Effect of alcohol on the nose and throat? Of tobacco? 163. On the 
 lungs? Does alcohol prevent consumption? 164. What is asthma? 
 165. Where are the blood-vessels of the lungs situated? 166. What 
 is the pleura? Its use? What is pleurisy? 167. How is inspiration 
 effected? What are the situation and use of the diaphragm? What is 
 hiccough (foot-note) ? 168. How is expiration effected ? 169. Which 
 is the more powerful action, inspiration or expiration ? 170. How 
 much air is taken into the lungs with each inspiration ? What is the 
 entire capacity of the lungs ? How much air can be expelled with a 
 forcible expiration? 171. What is meant by the diffusion of gases? 
 What is the function of the cilia? How is the air in the lungs changed 
 otherwise than by respiration ? 172. How much air is respired daily? 
 How would you calculate the amount? 173. What is the composition 
 of air as it enters the lungs ? How is it changed there ? How much 
 water is expired daily? 174. How much oxygen disappears in the 
 
QUESTIOXS. 321 
 
 body ? How was the carbon dioxide formerly supposed to be formed ? 
 How can this theoiy be disproved ' 175. What gives the breath its 
 peculiar odor? 176. How is the blood changed in the lungs? What 
 is the cause of the change in color (foot-note)? 177. Where is the 
 carbon dioxide found? How much is expired daily? 178. Effect of 
 alcohol on the respiration ? Of opium ? Effect of opium on the secre- 
 tions ? 179. How is the air changed by respiration ? Importance of 
 moisture in the air (foot-note). 180. Effect of plants on the compo- 
 sition of the air. 181. How does the air of houses become unfit to 
 breathe ? What is the effect of combustion ? What is the most dan- 
 gerous impurity added to the air by the breath? 182. What is ven- 
 tilation? How can it be effected? What becomes of the organic 
 matter of the breath in the open air? 183. What are contagious dis- 
 eases ? How are they communicated from one person to another ? 
 Malarial fevers, sewer-air (foot-notes). 184. How are these diseases 
 prevented from spreading? What precautions are to be taken in the 
 sick-room ? And why ? 
 
 Chapter VIII. — 185. What is asphyxia? How produced? How 
 is the color of the surface of the body affected by it ? 186. How long 
 may a person remain under water without dying? 187. What should 
 be done to resuscitate a person who has been under water until he is 
 unconscious? And why? 188. What is the object of artificial respi- 
 ration ? Describe the method of performing it. What is the first sign 
 of recovery? i8g. What precautions are necessar}' with regard to the 
 throat and tongue? What should be done when the person begins to 
 breathe ? Importance of fresh air (foot-note). 
 
 Chapter IX. — igo. How is the circulation of the blood effected? 
 
 191. What is the heart ? Its situation ? What is the pericardium ? 
 
 192. Describe the double circulation. 193. Describe the course of the 
 blood in the two sides of the heart. Why does the blood always go 
 forward and never backward? 194. How is each side of the heart 
 divided ? How many cavities are there altogether ? What are they 
 called ? What is the course of the blood through them ? 195. How 
 many sets of valves has the heart ? Where are they situated ? What 
 is their use ? 196 What large blood-vessels are connected with the 
 heart ? 197. Describe the circulation of the blood more fully. 198. 
 What peculiarity in the arrangement of certain valves in the heart ? 
 And what is the effect of this peculiarity? 199. How does the heart 
 contract and relax? 200. What are the sounds of the heart? How 
 are they produced? 201. How is the beating of the heart regulated? 
 202. How frequently does the heart contract? How may the rapidity 
 of contraction vary, and what conditions affect it ? Can its contrac- 
 
322 QUESTIONS. 
 
 tions ever be controlled by the will ? Give illustration. 203. Effect 
 of alcohol upon the heart ? How is a fatty heart produced by it ? 
 204. Effect of tobacco on the heart ? To what are the evil effects of 
 cigarette-smoking due ? 
 
 Chapter X. — 205. How is the work of the heart assisted ? 206. 
 What is the structure of the arteries ? How many layers ? What is 
 the use of the elastic fibers ? 207. How is the pulse produced ? Where 
 can it be felt ? 208. How do the arteries divide into branches, and how 
 do their walls change as they become smaller? 209, What are the 
 capillaries? How large are they ? How numerous? Illustrate. 210. 
 What is the structure of the veins ? What is the result of their struct- 
 ure? What are the venae cavse? 211. What effect has respiration on 
 the flow of blood in the veins ? And how ? 212. What effect has mus- 
 cular contraction? And how? 213. What is the use of the valves in 
 the veins? How can this be illustrated ? 214. How do the capillaries 
 assist the venous flow? 215. What is said of communicating blood- 
 vessels? 216. Give a brief review of the course of the circulation. 
 How rapidly does the blood flow in the arteries ? How rapidly in the 
 capillaries? Describe the circulation as seen in the frog's foot. How 
 does the blood nourish the tissues? What is the lymph? 217. What 
 artery carries black blood, and what vein scarlet blood? And why? 
 218. How rapidly does the blood flow in the veins? Why is not the 
 rapidity of the blood-current the same in arteries and veins? 219. How 
 rapid is the general circulation ? What experiment has been made to 
 determine this ? How long does it take for all of the blood to pass 
 through the heart ? How is this calculated? 220. What are the vaso- 
 motor nerves? How do they affect the circulation? 221. Effect of 
 alcohol upon the blood-vessels ? 222. What diseases of the vessels 
 are produced by it ? What is aneurism ? How may apoplexy be 
 caused ? 223. What* permanent change in the features may be pro- 
 duced by alcohol ? 224. What is the aorta ? What is its course ? 
 225. What are the femoral arteries? Their course? 226, What are 
 the brachial arteries ? Their course ? The radial and ulnar arteries ? 
 227. What arteries supply the head and face ? What is the course of 
 the carotid arteries ? 228. Where are the veins usually situated ? 
 What are the jugular veins ? What other large and important veins are 
 there? How many pulmonary arteries ? How many pulmonary veins ? 
 
 Chapter XI. — 229. What happens when the circulation of blood 
 in any part of the body is obstructed? Illustrate. How is the swelling 
 caused? What is dropsy? What happens when the obstruction is re- 
 moved? 230. What is the result of disease of the valves of the heart? 
 How is shortness of brca'.h produced? How is general dropsy pro- 
 
QUESTIONS. 323 
 
 duced by such disease ? What is the result of disease of the aortic 
 valves ? What may result from inflammation of the edges of the 
 valves? How may gangrene be caused? 231. How do physicians 
 detect heart-disease? 232. Effect of coagulation on bleeding. 233. 
 What are some of the conditions of coagulation ? Illustrate. 234. 
 How can the bleeding from an artery be distinguished from that from 
 a vein ? 235. How does Nature stop haemorrhage ? 236. How does 
 cold arrest bleeding ? 237. What are styptics? Name some of them. 
 W^hat is their effect on the blood? What is the objection to their 
 use? 238. How is compression applied to a wound? Where should 
 an artery be compressed? And a vein? 239. How does Nature arrest 
 bleeding permanently ? How do surgeons assist the process? What 
 is the use of ligatures? 240. State briefly the means of arresting 
 haemorrhage. 241. How is bleeding from wounds of the limbs to be 
 stopped? How is the knotted handkerchief to be used? 242. What 
 is the cause of fainting, and what is to be done for it? 243. What does 
 shortness of breath always indicate? Why does exercise cause it? 
 
 PART IV. 
 
 Chapter I. — 244. What is said of the difficulty of investigating 
 the nervous system ? 245. What are the two great divisions of the 
 nervous system? Wliat are they called? What are their functions? 
 246. What are the two forms of nervous tissue? 247. What is the 
 structure of the white substance? How large are nei've-fibers ? What 
 is the myelin? The axis-cylinder? What are supposed to be the 
 functions of these diff'erent parts of the nerve-fiber? 248. What does 
 the gray substance consist of? How large are nerve-cells? What is 
 their structure ? What relation is supposed to exist between the cells 
 and the fibers ? What is the function of the fibers ? What of the 
 cells? 249. What is the structure of a nerve? How do its constitu- 
 ent parts vary in different situations? What kind of nervous substance 
 is most abundant? 250. What are nervous ganglia? 251. Illustrate 
 the functions of sensation and motion as exhibited by nerves. What 
 is reflex action? Why so called? 252. What is said of the rapidity 
 of the nervous force ? Give an illustration. 253, Do nerves become 
 exhausted? How? 254. How can it be shown that nerves are mere 
 conductors of force ? 255. What are the reasons for believing that the 
 gray substance originates force ? How does the nerve-force difler 
 from electricity? 256. What part of the nervous system supplies the 
 voluntary muscles with nerves? And what part the involuntary ones? 
 What part is under our own control? 
 
324 QUESTIONS. 
 
 Chapter II. — 257. What is the structure of the sympathetic sys- 
 tem ? How large are the ganglia ? Where are they situated ? What 
 is said about the solar plexus (foot-note)? 258. What is said of the 
 rapidity of action of the sympathetic system ? How is it illustrated 
 in disease ? 259. How is it illustrated by the pupil of the eye ? 
 260. What is the effect of dividing a sympathetic nerve? How has 
 it been shown on the ear? What do these facts indicate? 261. If 
 the sympathetic nerve supplying a gland is divided, what effect is pro- 
 duced? How is "watering of the mouth" caused? 262. How is 
 blushing produced? Why is it more evident in the cheeks? What 
 facts show that it is regulated by the sympathetic nerves ? How can 
 the blush be prevented? 263. What are the vaso-motor nerves? Why 
 so called? Are the cerebro-spinal and sympathetic systems entirely 
 distinct from each other ? 264. What system regulates the process of 
 digestion? How may this process be affected by the emotions? 265. 
 What effect has cold on the sympathetic nerves ? How may serious 
 disease be brought on by exposure ? How do persons catch cold, and 
 how may colds be prevented (foot-note)? 266. What ai'e the signs of 
 exhaustion of the sympathetic system? How is it to be relieved? 
 
 Chapter III. — 267. Describe the spinal cord. How are the gray 
 substance and the white substance arranged respectively ? What are 
 the fissures of the cord? 268. How many pairs of spinal nerves are 
 there ? What parts of the body do they supply ? 269. What are the 
 properties of the spinal nerves ? 270. What two kinds of sensibility 
 exist in these nerves? How is this shown ? 271. What is the effect of 
 dividing a spinal nerve? How can sensation and motion both be con- 
 veyed by the same nerve? 272. How many roots has a spinal nerve? 
 How does the posterior root differ in appearance from the anterior ? 
 How are the spinal nerves formed, and how do they divide? 273. 
 What effect is produced by dividing the anterior root of a spinal nerve ? 
 What does this experiment prove? 274. What effect is produced by 
 dividing the posterior root of a spinal nerve ? What does this experi- 
 ment prove ? 275. What do these experiments show with regard to the 
 structure of spinal nerves? 276. How is the spinal cord connected 
 with the brain ? What is said of the crossing of fibers from one side to 
 the other? 277. Why are sensations always referred to the extremity 
 of the nerve ? Give illustrations. 278. What is the use of the gray 
 matter in the center of the spinal cord ? Describe the experiment with 
 the frog. What does it show ? 279. How does Nature perform simi- 
 lar experiments for us upon men? Illustrate. 280. What are auto- 
 matic actions ? Illustrate. 
 
 Chapter IV. — 281. What is the distinction between the brain and 
 
QUESTIONS. 325 
 
 the cerebrum ? What is said of the removal of the cerebrum ? 282. 
 What is the structure of the cerebrum? What are the convolutions? 
 How is the gray matter distributed ? Is the cerebrum sensitive to in- 
 jury? 283. What is the function of the cerebrum? 284. Does intel- 
 ligence seem to increase with the size of the brain ? Illustrate. What 
 is the weight of the human brain? 285. How much do human brains 
 differ in weight? Illustrate. How would you account for a small 
 brain in a clever man ? 286. What effect do injunes of the brain have 
 upon the mind? 287. What is the effect of softening of the cerebrum 
 in man? 288. State briefly the evidence that the cerebrum is the seat 
 of intelligence ? 289. What is the structure of the cerebellum ? Its 
 size? 290. What is the effect of disease or injury of this organ in 
 man ? What is inferred from these facts as to the function of the 
 cerebellum? 291. What is the function of the tubercula quadrigem- 
 ina? How can this be proved? Where do the powers of sensation 
 and motion reside ? How is this shown ? 292. Describe the situation 
 and relations of the medulla oblongata. What is the vital knot? 293. 
 How are the movements of respiration regulated by the medulla ob- 
 longata? 294. Illustrate the automatic action of this ganglion. What 
 is the result of its destruction ? 
 
 Chapter V. — 295. How do ihe nerves of the brain differ from the 
 spinal nerves? Which are the most important ones? What parts does 
 the trigeminal nerve supply? What is its function? What parts are 
 supplied by the facial nerve? What is its function? How may it be 
 affected by exposure to cold ? 296. What is the course of the sciatic 
 nerve? What is the cause of the foot " being asleep " ? 297. What 
 is the importance of reflex action ? Give illustrations (foot-note). 
 
 298. Why is education so important? \\'hy are habits easily formed 
 in the young? Why do they need the guidance of older persons? 
 
 299. Why is it important that the brain should have sufficient exercise? 
 
 300. What is the effect of over-exercise? 301. Why is sleep necessary ? 
 What takes place during sleep? Why do we wake up? What is the 
 best time for sleep ? Why ? How much sleep is necessary ? 302. 
 What is said of abuse of the nervous system, and its danger? 303. 
 Effect of a small amount of alcohol upon the nen'ous system ? 304. 
 Of a larger dose? How is double vision produced? 305. Effect of 
 very large doses? After-effects? 306. How is alcohol supposed to 
 cause these results? 307. W^hat is chronic alcoholism? Its symp. 
 toms? 308. How is delirium tremens caused ? Its symptoms? How 
 may it end? 309. Effect of alcohol upon the moral nature? 310. 
 Effect of alcohol on nervous tissue? 311. How may children suffer 
 from the drinking habit of the parents ? 312. What poisonous substances 
 
 22 
 
326 QUESTIONS. 
 
 besides alcohol are found in alcoholic drinks ? Their effect upon the 
 body? 313. Effect of tobacco on the nervous system? How does it 
 produce its so-called soothing effect ? What bad results may follow its 
 use? How are they to be accounted for? 314. What marked differ- 
 ence in the effects of alcohol and opium? 315. Effect of a small dose 
 of opium ? 316. Of a larger dose ? 317. Of a dangerously large dose ? 
 318. How is the opium-habit formed ? 319. Effects of opium on the 
 mental, moral, and physical nature ? 320. Effect of the chloroform- 
 habit? 321. Of the chloral -habit ? 322. Explain the cause of the 
 craving due to the habitual use of narcotics. 
 
 PART V. 
 
 Chapter I. — 323. In what points do the skin and mucous mem- 
 brane resemble each other? What are the functions of the skin ? 324. 
 What is the structure of the skin ? The epidermis ? The derma ? 
 How thick is the skin ? 325. How is the skin connected with the tis- 
 sues beneath it ? What are the papillae ? Their situation, size, and 
 arrangement ? 326. What causes ihe difference of complexion in dif- 
 ferent persons? What is an albino? What seems to be the use of the 
 pigment-cells? 327. What are the nails? How do they grow? W^hat 
 is the use of them ? 328. What are the hairs ? How do they grow ? 
 What causes the difference in color of the hair in different persons? 
 How much of the body is covered with hair? 329. What are the seba- 
 ceous glands? What is their structure? Where are they situated ? 
 What is their function ? What is the result when their openings are ob- 
 structed ? 330. What are the sweat-glands ? Where are they situated ? 
 What is their structure? How large are they, and how numerous? 
 
 Chapter II. — 331. What is the effect of pressure on the skin? 
 What diseases may be produced by it ? 332. What was Lavoisier's theory 
 of the cause of animal heat? How overthrown? Liebig's theory? 
 What objection is there to it? What is believed to be the true theoiy? 
 333- What is the normal temperature of the human body ? How much 
 may it vary ? 334. What is the effect of a great fall or a great rise in 
 the temperature of the body? What external temperatures are we 
 often exposed to ? 335. What is the effect of a low external tempera- 
 ture on the body? How is the appetite affected ? How does the body 
 accommodate itself to such a temperature ? 336. What is the effect 
 upon the body of a high external temperature ? 337. How is the tem- 
 perature of the body regulated by the perspiratory glands ? 338. Does 
 alcohol increase or diminish the power of endurance ? Explain its 
 effect in extreme cold and heat. Give illustrations. 339. What is 
 
QUESTIONS, 327 
 
 the insensible perspiration ? What is its daily amount ? How may it 
 be immensely increased ? 340, What is the effect of exposure to dry 
 heat ? 341. What is the effect of exposure to moist heat ? 342. What 
 is said of respiration through the skin ? How much carbon dioxide is 
 thrown off by it (foot-note) ? What is said of absorption through the 
 skin (foot-note) ? 343. How does the skin become covered with im- 
 purities ? Why should these be removed ? 344. What is the effect of 
 a cold bath? How long should the bath last ? 345. What is the effect 
 of a warm bath ? Vv''hy should exposure to cold be avoided after it ? 
 346. State the rules for bathing and the reasons for them ? 347. How 
 should the face and hands be cleaned ? What is the objection to soap? 
 How is " chapping " produced ? How may it be prevented ? What is 
 the best soap? 348. What causes dandruff? How should the scalp 
 be cleaned ? What is said about cleaning and cutting the hair ? 349. 
 How should the nails be cut ? Why should they not be cut close to 
 the flesh ? What causes " hangnails " ? How may they be prevented? 
 What causes the white spots on nails ? 350. What is the object of 
 clothing ? What is the best material to wear next the skin ? Why ? 
 Why is linen bad for this purpose ? Why should the under-clothing 
 be changed at night ? What is said of tight and high-heeled shoes ? 
 What are the general rules for the selection of clothing ? 
 
 PART VI. 
 
 Chapter I. — 351. Where does the sense of touch have its seat? 
 How do the nerves end in the papillse of the skin ? 352. W^hat do we 
 learn by the sense of touch ? How does the sensitiveness of the skin 
 vaiy in different parts of the body ? How is this shown ? What is the 
 most sensitive part (foot-note)? 353. Can the extremes of sensation 
 be easily distinguished from each other? What is said of deception 
 through the senses ? Give illustrations (foot-note). 354. What rela- 
 tion do the special senses bear to the sense of touch ? What pecul- 
 iarity is common to them? 355. Where is the sense of taste located ? 
 How are the nerves of taste distributed to the tongue ? How do they 
 terminate ? How do we taste ? 356. How many modifications of the 
 sense of taste are there? What qualities are perceived in the mouth by 
 the sense of feeling ? Is the aroma of a substance tasted or smelled ? 
 How may this be determined? 357. Why do substances have a dif- 
 ferent taste on the front and back of the tongue? Give illustrations. 
 Why does the sensation of taste persist for a time after the substance 
 has been removed ? How does this affect the detection of delicate 
 flavors ? W^hy do we smack our lips when tasting ? What is the use 
 
328 QUESTIONS. 
 
 of this sense ? 358. Where does the sense of smell reside ? What is 
 the olfactory nerve ? Its situation ? How much of any substance is 
 required to affect the sense of smell ? Why do we sniff at odors in 
 order to appreciate them (foot-note) ? Illustrate the occasional diffi- 
 culty of distinguishing between the sense of smell and that of feeling. 
 359. Illustrate the acuteness of this sense in some men and lower ani- 
 mals. What is the use of this sense ? 
 
 Chapter IL — 360. What kind of impressions are perceived by the 
 sense of hearing ? 361. What are the three divisions of the ear? What 
 is the use of the external ear ? Is it movable ? 362. What is the tym- 
 panum ? How do the air-waves reach it ? What is the middle ear ? 
 Its situation and size ? What is the Eustachian tube ? Its use ? 363. 
 Where are the bones of the ear ? How many are there, and how large ? 
 What are they attached to, and how are they moved ? 364. What is 
 the structure of the internal ear ? What are its chief parts, and what 
 is it filled with ? How is the nerve of hearing distributed ? 365. How 
 is hearing effected ? 366. Upon what do the different qualities of 
 sound depend? 367, How do we determine the direction from which 
 sound comes ? What is said of the function of the semi-circular canals 
 (foot-note)? 368. What is ventriloquism? How are its effects pro- 
 duced ? 369. How is the ear protected from insects ? How can they 
 be removed when they have entered the ear ? What is said of the use 
 of ear-scoops? 370. How may colds in the head affect the hearing? 
 How may permanent deafness be caused ? Influence of alcohol and 
 tobacco in causing deafness ? 
 
 Chapter III. — 371. How does the sense of sight differ greatly 
 from the other senses? 372. What is light believed to be? How 
 rapidly does it travel? Describe the wave theory of light. 373. How 
 is the eye protected? 374. What is the shape of the eyeball? Its 
 size? The three membranes? Their situation and structure? 375. 
 What is the vitreous humor? What are muscce volitantes (foot-note) ? 
 The crystalline lens ? The iris ? The aqueous humor ? 376. What 
 is the use of the sclerotic coat ? Of the cornea ? Of the choroid ? 
 What is the cause of "dazzling" ? What peculiarity have the eyes of 
 albinos (foot-note) ? 377. What is the structure of the retina? What 
 is the blind-spot ? How may its existence be demonstrated ? Why 
 does it not interfere with sight ? 378, What is the use of the lens ? 
 379. What change takes place in the eye to enable us to see either 
 near or far objects at will? How is this change produced? What is 
 the ciliary muscle? Its function? 380. What is the inner limit of 
 distmct vision ? The farther limit ? (In healthy eyes it is practically 
 infinitely distant.) 381. What causes the color of the iris? What are 
 
QUESTIONS. 329 
 
 the functions of the iris? What are spherical and chromatic aberra- 
 tion ? How are they prevented by the iris? 3S2. How is it shown 
 that the optic nerve conveys only the sensation of light ? 3S3. Illus- 
 trate the persistence of impressions on the retina. 3S4. What is meant 
 by "color-blindness"? 385. Explain near-sightedness and far-sight- 
 edness. 386. How is the eyeball moved? 387. What are the uses of 
 the eyelids, eyebrows, and eyelashes? 388. What are the tears? 
 Where do they come from, what is their use, and what becomes of 
 them ? How is weeping explained ? How are the tears prevented 
 from overflowing on to the cheeks ? 3S9. Effect of excessive use of 
 tobacco upon the eyes? What is tobacco-amaurosis? 390. What is 
 said of the care of the eyes ? Of their delicacy ? Why is it bad to 
 strain them ? Why should they not be opened under cold water (foot- 
 note) ? What abuses of the eye should especially be avoided ? 
 
 PART VII. 
 
 391. What is the larynx? Its structure, situation, and shape? 
 
 392. What are the vocal chords ? How are they moved (foot-note) ? 
 
 393. How is the voice produced ? How is it modulated ? 394. How 
 is the larynx commonly abused ? What effect has inflammation of the 
 vocal chords upon the voice ? How is " breaking " of the voice pro- 
 duced? 395. Why is rest necessary when the vocal chords are inflamed? 
 
GLOSSARY. 
 
 Abdo'men. That portion of the trunk of the body which is situated 
 between the diaphragm and the pelvis. The tissues surrounding 
 and inclosing it, the muscles, skin, bones, etc., are called the ab- 
 dominal walls. 
 
 Accommodation. The adjustment of the internal parts of the eye in 
 correspondence with the varying distance of external objects, so 
 that their images always fall upon the retina. 
 
 Albino. (Portuguese, from Latin, albiis,\\\\\\.t..) An animal in which 
 pigment-cells are lacking, so that the hair and skin are white, and 
 the pupil of the eye red. 
 
 Albu'men. (A Latin word, signifying the white of an egg, which is 
 almost pure albumen.) A very nutritious substance of very complex 
 chemical composition, constituting a large part of meats and some 
 vegetables, and classed with the nitrogenous foods or proteids (q. v.). 
 
 Alcohol. (From the Arabic.) The common name of what chemists 
 call ethyl-alcohol. Produced, together with carbon dioxide, by the 
 fermentation of liquids containing sugar. Is present in all fer- 
 mented fluids, the distilled liquors containing from 50 to 60 per 
 cent ; heavy wines, port, sherry, etc., 16 to 25 per cent ; clarets 
 and hocks, 7 to 16 per cent ; and malt liquors, 2 to 10 per cent. 
 
 Alimentary Canal. The long tube extending from the mouth down- 
 ward through the body, by which food is received, digested, ab- 
 sorbed, and the residue expelled. It includes the mouth, pharynx, 
 oesophagus, stomach, small intestine, and large intestine. 
 
 Anatomical Element. A portion of a living body so small that it can 
 not be further divided without the destruction of its organization. 
 
 Anatomy. (Greek, avarofi-f], a cutting up.) The science that describes 
 the appearance, structure, and situation of the diff'erent parts of the 
 body. 
 
 Aor'ta. (Greek, aopr-fi.) The large artery which first receives the 
 blood from the left ventricle of the heart. 
 
33^ 
 
 GLOSSARY. 
 
 Apoplexy. (Greek, aToirK'n^ia, a sudden stroke.) The escape of blood 
 from a broken blood-vessel into the substance of the brain. 
 
 Apparatus. A number of organs, differing in size and structure, which 
 work together for the accomplishment of a particular object, e. g., 
 the digestive apparatus, comprising the stomach, liver, pancreas, 
 intestines, etc. 
 
 Appen'dix Vermifor'mis. (Latin, meaning the worm-like appendage^ 
 A small projection from the csecum (q. v.), about six inches long 
 and half an inch wide, of the same general structure as the intes- 
 tine, situated in the right groin, and of no apparent use. Small ob- 
 jects, such as cherry-pits, grape-seeds, etc., sometimes lodge in it, 
 and give rise to a fatal inflammation. 
 
 A'queous Hu'mor. (Latin, aqua, water.) A fluid in the eye lying 
 between the crystalline lens and the cornea, consisting almost en- 
 tirely of water, with a little salt. 
 
 Ar'tery. (Greek, aprTjpla, from arjp, air, and TTjpeti/, to contain, because, 
 being always found empty after death, they were supposed to contain 
 air during life.) A blood-vessel carrying blood away from the heart, 
 
 Asphyx'ia. (Greek, aacpv^ia, pulselessness.) Suffocation. 
 
 Asth'ma. (Greek, acrOfjia, a gasping or panting.) A spasmodic affec- 
 tion of the lungs, in which the caliber of the small bronchial tubes 
 is diminished so much as to interfere with free respiration. 
 
 Au'ditory Nerve. The nerve of hearing. 
 
 Au'ricles. (Latin, auris, the ear ; called auricles from their fancied 
 resemblance to ears.) Two cavities of the heart into which the 
 blood first enters as it returns from the rest of the body. 
 
 Axis-Cylinder. A transparent or finely granular thread running in 
 the center of every nerve-fiber, and believed to be the part along 
 which the nerve- current passes. 
 
 Bacte'ria. (Greek, l3aKTi]pLoi/, a staff.) Small organisms, only visible 
 under the microscope, shaped like rods, and believed to be the 
 cause of many diseases. 
 
 Bi'ceps. (Latin, biceps, two-headed.) The large muscle extending on 
 the front of the arm from the shoulder to the elbow. So called be- 
 cause it is attached to two different points of the shoulder, i. e., by 
 two headso 
 
 Blood-Corpuscles. The microscopic bodies which float in vast num- 
 bers in the blood, and are the most essential constituent of it. 
 
 Brach'ial. (Latin, brachium, the arm.) Pertaining to the upper arm, 
 as the brachial artery. 
 
 Bron'chi. (Latin.) The tubes into which the trachea or windpipe 
 is divided, and which convey air to the interior of the lungs. 
 
GLOSSARY. 
 
 
 Bronchi'tis. Inflammation of the mucous membrane lining the 
 bronchi. 
 
 Cae'cum. (Latin, cccciis, blind.) The beginning of the large intestine. 
 So called because it bulges downward from the point where the small 
 intestine enters it, and forms a sort of cul-de-sac, or blind pouch. 
 
 Capillaries. (Latin, capillus, a hair.) The microscopic blood-ves- 
 sels through which the blood passes from the arteries to the veins. 
 
 Carbon Dioxide. Often called carbonic acid. A gas containing one 
 part of carbon to two of oxygen. When inhaled it produces insen- 
 sibility, followed by death if the inhalation is continued. 
 
 Carbonaceous Foods. Foods containing a large proportion of car- 
 bon but no nitrogen. They also contain hydrogen and oxygen ; 
 and, if the latter constituents are in the same proportion as in water, 
 e. g., in starches and sugars, the foods are called carbohydrates ; 
 otherwise, hydrocarbons, e. g., the oils and other fats. 
 
 Car'diac Orifice. (Greek, Kapdia, the heart.) That opening of the 
 stomach by which food enters. So called because it is nearest the 
 heart. 
 
 Carot'id Arteries. (Greek, KapcoriSes, same meaning.) The large 
 arteries supplying the front of the head and face. 
 
 Car'tilage. (Latin, carti/ago, same meaning.) A bluish-white, elastic 
 substance, found in various situations in the body, but especially 
 covering the ends of bones which form joints. 
 
 Ca'sein. (Latin, cascns, a cheese.) A nitrogenous substance or pro- 
 teid (q. v.), forming the chief part of the curd of milk, often pressed 
 into cheese. 
 
 Catarrh. (Greek, Kardphoos, a morbid discharge.) An acute or 
 chronic inflammation of a mucous membrane, usually attended by 
 an increased secretion of mucus. 
 
 Cau'da Equi'na. (Latin, meaning a horse s tail.) The lower end of 
 the spinal cord, so called because it is split up into strings of nerves 
 resembling somewhat a tassel or a horse's tail. 
 
 Cerebel'lum. (Latin, signifying a litfk brain) A portion of the 
 brain, constituting a distinct ganglion, situated under the posterior 
 part of the cerebrum. 
 
 Cer'ebro-spinal System. The brain and spinal cord, with the neiwes 
 rrising from them. 
 
 Cer'ebrum. (Latin, meaning the brain.) The larger and upper part 
 of the nervous mass lying within the skull, and conceded to be the 
 seat of the intellect. 
 
 Chlo'ral. A narcotic poison, formed from chlorine and alcohol. Used 
 internally to produce sleep. 
 
334 
 
 GLOSSARY, 
 
 Chloroform. A narcotic poison produced by the distillation of chloride 
 of lime and alcohol, and generally used by inhalation. It produces 
 anaesthesia, with complete unconsciousness, and is therefore useful 
 in surgical operations. 
 
 Cho'roid Coat. (Greek, xop'O"* leather, because of its dark, leather- 
 like color.) The middle coat of the eye, containing numerous pig- 
 ment-cells and blood-vessels. 
 
 Chromat'ic Aberration. (Greek, XP^I^"'' color.) The splitting up of 
 white light into colored light as it passes through a lens, in conse- 
 quence of the difference in the refrangibility of its components. 
 The image produced in the focus of such a lens will be fringed 
 with color. The violet rays, being the most rapid in their undula- 
 tions, are brought to a focus first, and the red rays, being the slow- 
 est, last, so that if a screen be placed in the focus of the violet rays, 
 when a lens is not achromatic, the image will be fringed by red rays, 
 which have not yet converged to a focus ; and if the screen be put 
 in the focus of the red rays, the image will be fringed by violet rays, 
 w^hich have passed their focus, and begun to diverge. 
 
 Chyle. (Greek, x"'^'^^* same meaning.) The whitish fluid that is ab- 
 sorbed from the intestine into the lacteals. 
 
 Chyme. (Greek, x^l^'^^^ juice.) The grayish, pulpy fluid into which 
 food is converted in the stomach. 
 
 Cilia. (Latin, dlium, an eyelash.) Hair-like projections on the free 
 extremity of certain epithelial cells. 
 
 Cil'iary Muscle. A small, circular muscle in the interior of the eye- 
 ball, which assists in the function of accommodation. 
 
 Ciliated Epithelium. Epithelium having cilia on the free extremi- 
 ties of the cells. 
 
 Cochlea. (Greek, Kox^'^as, a spiral shell.) A portion of the internal 
 ear, shaped like the interior of a snail-shell. 
 
 Com'press. A pad or bandage applied directly to a wound, in order 
 to compress it. 
 
 Connective Tissue. A delicate lace-work of fibrous threads which 
 extends through all organs of the body, binding their elements to- 
 gether. 
 
 Convolutions of the Brain. The projections on the surface of the 
 brain, which look somewhat like those of a walnut-meat. 
 
 Co-ordination. The bringing of several different things into such 
 relations with one another that they perform their functions in har- 
 mony. 
 
 Cor'nea. (Latin, cor'nu, a horn.) The transparent portion of the ex- 
 ternal coat of the eye. 
 
GLOSSARY, 
 
 zy. 
 
 Crys'talline Lens. The lens of the eye, by which light is brought to 
 a focus on the retina. 
 
 Cutis. (Latin, meaning the s km.) The true skin, containing the hair- 
 bulbs, blood-vessels, nerves, etc. The hard, insensitive layer out- 
 side of the cutis is called the cuticle, i. e., the little skin. 
 
 Cysticer'cus Cellulo'sae. (Part Latin and part Greek, kixttis, a blad- 
 der, KepKos, a tail, and cellida, meaning the bladder-tailed animal of 
 the cellular [or connective] tissue.) A parasite, found in measly 
 pork. When eaten by a human being, it is developed into a tape- 
 worm in the intestine, 
 
 Der'ma. (Greek, Sep/io, the skin.) Same as cutis (q. v.). 
 
 Diaphragm. (Greek, 5id(ppayfjLa, a partition.) The muscular partition 
 which separates the thorax, or chest, above, from the abdomen below. 
 
 Disinfectants. Drugs which destroy the germs or particles of living 
 matter that are believed to be the causes of various diseases. 
 
 Dislocation. The displacement of the end of a bone. 
 
 Drum of Ear. The membrane which separates the middle ear from 
 the external ear, and on which the air-waves (sound-waves) first 
 strike. 
 
 Duodenum. (Latin, diwdeni, twelve each.) The first eight or ten 
 inches of the small intestine nearest the stomach. So called be- 
 cause its length is about twelve fingers' breadth. It differs some- 
 what in structure from the remainder of the intestines, and is a little 
 larger. 
 
 Epidermal Cells. The cells composing the epidermis. 
 
 Epider'mis. (Greek, eVt, upon, and Sep^a, the skin.) The same as 
 cuticle (q. v.). 
 
 Epiglot'tis. (Greek, eV^, upon, and yXuTTis, the glottis.) A leaf- 
 shaped cartilage, covered with mucous membrane, situated at the 
 base of the tongue, just above the glottis. 
 
 Epithelium. (Greek, iirl, upon, and ^tjAtj, a nipple.) A general term 
 applied to various kinds of cells which cover all the free surfaces of 
 the body, and are called epithelial cells. 
 
 Ether. (Greek, aldrjp, the pure upper air.) A narcotic poison, made 
 by distilling sulphuric acid with alcohol, and used as an ancesthetic 
 in surgical operations. 
 
 Ether, The. A very subtile form of matter, which is supposed to 
 fill all space, permeating all bodies, to the vibrations of which the 
 phenomena of light and heat, electricity and magnetism, are believed 
 to be duCo 
 
 Eusta'chian Tube. (From Eustachi, its discoverer.) The tube or 
 canal leading from the middle ear to the throat. 
 
336 GLOSSARY. 
 
 External Auditory Canal. The canal or tube leading from the ex- 
 ternal ear inward to the drum. 
 
 Facial Nerve. The motor nerve of the face. 
 
 Fem'oral Artery. (LdXm., femzcr, the thigh.) The main artery of the 
 thigh. 
 
 Fiber. A slender, microscopic thread of nitrogenous matter, veiy 
 strong, tough, and elastic. When these threads are delicate, and 
 loosely woven, they form connective tissue. When larger and more 
 closely woven, and with a tendency to a longitudinal arrangement, 
 they make fibrous tissue. There are other differences between 
 these tissues, but they are too technical for insertion here. 
 
 Fi'brin, A nitrogenous material contained in the flesh of animals, and 
 classed among the proteids. It is also produced by the coagulation 
 of blood, constituting the greater portion of the clot. 
 
 Fol'licles. {Ldiim, folliculus, a little sack or pouch.) A name applied 
 to little pits or depressions in the skin or mucous membrane, out 
 of which is poured a secretion, differing in different situations. 
 
 Frontal Si'nuses. Cavities in the bones of the skull, just over the 
 eyebrows, the front wall causing the projection noticeable there. 
 
 Function. (Latin, /«mc/?c, from yW;«§^r, to perform.) The work per- 
 formed by any organ of the body is called its function. 
 
 Ganglion. (Greek, ydyyKiov, a tumor.) A name applied to certain 
 masses of gray nerve-matter, which have independent functions, 
 and are separated from other masses of gray matter by intervening 
 white matter. 
 
 Gangrene. (Greek, ydyypaiva, gangrene.) Death of a portion of the 
 soft parts of the body, while still attached to the living tissues. 
 Generally caused by deprivation of blood. 
 
 Gastric. (Greek, yaar-fip, the belly.) Pertaining to the stomach. 
 
 Gland. (Latin, glans, an acorn.) An organ which separates some- 
 thing from or adds something to the blood that passes through it, 
 by its own activity. 
 
 Glot'tis. (Greek, ykcoTTls, the glottis.) The upper opening of the 
 larynx. 
 
 Glucose. (Greek, yKvKvs, sweet.) A kind of sugar, also called grape- 
 sugar, found in fruits in considerable quantity. Produced artifi- 
 cially by the action of a mineral acid on starch. Cane-sugar is con- 
 verted into glucose in the stomach. 
 
 Graduated Compress. vSeveral pads of soft material, of different 
 sizes, placed upon each other with the smallest underneath and the 
 largest on top. Used for compression of wounds. 
 
 Granular Matter. Microscopic particles of matter, generally of a 
 
GLOSSARY. 337 
 
 nitrogenous nature, found in great quantity in certain tissues in 
 the form of fine granules, whose precise character and function are 
 not yet determined. 
 
 Gray matter. The ash-colored portion of the nervous system, con- 
 sisting mainly of nerve-cells, and believed to originate nerve-force. 
 
 Great Pouch of the Stomach. The enlargement of the stomach 
 toward the left of the cardiac orifice. 
 
 Haemoglobin. (Greek, aXfxa, blood, and Latin, globus, a sphere.) The 
 coloring-matter of the blood, consisting of a proteid substance in 
 combination with iron, and making up the greater part of the blood- 
 corpuscles. 
 
 Homologous Bones. Those bearing similar relations to adjacent 
 parts, and having similar special functions. 
 
 Hygiene. (Greek, vyi^iuSs, healthy.) The science which describes 
 what is healthful and what is injurious to the body, and how health 
 may be maintained. 
 
 Insensible Perspiration. Perspiration which is too small in quantity 
 to collect in drops, and is therefore not ordinarily perceived. 
 
 Internal Ear. That part of the ear which lies imbedded in bone, 
 and in which the branches of the nerve of hearing are dis- 
 tributed. 
 
 Involuntary Muscles. Those that are not under the control of the 
 will. 
 
 Iris. (Greek, Jpis, a rainbow.) The colored muscular curtain in the 
 front of the eyeball which surrounds the pupil ; so called on ac- 
 count of its variety of color. 
 
 Jaundice. A disease, in which the coloring-matter of the bile is found 
 in the blood and stains all the tissues yellow. 
 
 Jug'ular Veins. (Latin, jugtdum, the neck.) The large veins in 
 the neck which return the blood from the head and face. 
 
 Labyrinth. A portion of the internal ear, so called from its winding 
 passages. 
 
 Lach'rymal. (Latin, lacktyvia, a tear.) Pertaining to the tears, as 
 the lachrymal gland, which secretes them. 
 
 Lac'te^ls. (Latin, iac, lactis, milk.) Those vessels of the lymphatic 
 system which absorb the chyle from the small intestine and appear 
 like white threads and cords during digestion. 
 
 Lar'ynx. (Greek, \dpvy^, the larynx.) The organ of voice, situated at 
 the top of the windpipe, producing the protuberance in the neck 
 commonly known as Adam's apple. 
 
 Latis'simus Dor'si. (Latin, meaning the broadest of the back.) A 
 large, triangular muscle, attached throughout one side to the spine. 
 
338 GLOSSARY. 
 
 and at the opposite angle to the arm near the shoulder, the fibers 
 
 running from the spine to the arm. 
 Lens. (Latin, lens, a lentil.) A transparent substance bounded by 
 
 curved surfaces, so that light passing through it is refracted, i. e., 
 
 bent out of its course. So called from its shape. 
 Lig'ament. (Latin, ligamentum, a band.) A closely knit mass of 
 
 fibrous tissue, white, glistening, tough, and inelastic, which binds 
 
 bones together at the joints, 
 Lig'ature. (Latin, ligatura, a band.) A cord, used in surgeiy for 
 
 tying blood-vessels, so as to prevent or stop bleeding. 
 Lymph. (Latin, lympka, water. Poetic.) A yellowish, transparent, 
 
 saltish fluid, found in the lymphatic vessels. 
 Lymphat'ic Vessels. A system of tubes, varying in size, found in all 
 
 parts of the body, like the blood-vessels, possessing great absorbent 
 
 powers, containing always the lymph, which they collect and pour 
 
 into the large veins near the heart. 
 Lymphat'ic Glands. Small bodies, varying in size from a hemp-seed 
 
 to an almond, scattered at intervals along the lymphatic vessels, 
 
 which enter them and emerge again. Their functions are imper- 
 fectly known. 
 Marrow. The reddish, pulpy, fatty substance contained in the shaft 
 
 of the long bones. 
 Mas'seter Muscle. (Greek, fxaff-nr-hp, a chewer.) A square muscle, 
 
 attached to the skull and to the horizontal part of the lower jaw. 
 
 Used in bringing the jaws together. 
 Medul'la Oblonga'ta. (Latin, meaning \he pith or marrow lengthened 
 
 out.) An enlargement at the upper extremity of the spinal cord, 
 
 just as it enters the skull, but before its fibers diverge to the differ- 
 ent parts of the brain. One of its chief functions is the control of 
 
 respiration. 
 Middle Ear. A small cavity, containing the minute bones which 
 
 serve to conduct the sound-waves from the drum of the ear to the 
 
 internal ear. 
 Molec'ular. Pertaining to molecules, i. e., the smallest particles of 
 
 matter into which any substance can be divided without becoming 
 
 something else. 
 Motor. Producing or giving rise to motion. A motor nerve is one 
 
 whose function is to excite motion, instead of conveying sensation. 
 Mucous Membrane. The soft, velvety membrane which lines all 
 
 those cavities of the body which communicate with the external air. 
 
 It is continuous with the skin, and secretes a glairy fluid, which 
 
 keeps its surface constantly moist. 
 
GLOSSARY. 339 
 
 Mus'cae Volitan'tes. (Latin, vaezwing Jlitiing ^ies.) Little strings or 
 fibers, which float in the interior of the eye, and which can be 
 readily seen by looking at a white wall, appearing like strings of 
 beads, or transparent spheres clustered together, and moving when 
 the eye moves. Found in healthy eyes. Spots which remain fixed 
 imply disease. 
 
 Myelin. (Greek, ixve\6s, marrow.) The white nerve-matter which sur- 
 rounds the axis-cylinder (q. v.), and forms the bulk of the nerve-fiber. 
 
 Narcotic Poisons. (Greek, vapKSu, to benumb.) Poisons such as 
 opium, alcohol, ether, and chloroform, which produce at first, or in 
 small quantity, a feeling of exhilaration, followed, if more be taken, 
 by insensibility and death, or, if the person gets well, by a period 
 of depression, from which the system is slow to recover. 
 
 Nasal. (Latin, nasus, the nose.) Pertaining to the nose. 
 
 Nerve-Center. A mass of gray nerve-substance, believed to originate 
 the nerve-force. 
 
 Nitrogenous Foods. Substances, chiefly of animal origin, which con- 
 tain nitrogen, in addition to carbon, hydrogen, and oxygen. Many 
 of them also contain a little sulphur. 
 
 Non-nitrogenous. (See Carbonaceous.) 
 
 Nucleolus. Diminutive of nucleus. A small, bright particle of mat- 
 ter inside of a nucleus, and forming a part of it. 
 
 Nucleus. (Latin, «//.r, nucts, a nut.) A small body contained in the 
 interior of a cell, and forming a part of it. 
 
 Nystag'mus. (Greek, vvaTayixSs, a nodding.) An aff"ection of the 
 eye, in which the eyeball oscillates constantly from side to side. 
 
 CEsoph'agus. (Greek, ola-ocpdyos, the gullet.) The tube, about nine 
 inches long, that conveys substances from the throat to the stomach. 
 
 Olfact'ory. [l^atin, o//acio, to smell.) Pertaining to the sense of smell, 
 as the olfactory nerve. 
 
 Opium. A narcotic drug, obtained from the juice of the poppy. 
 
 Optic. (Greek, otttikSs, belonging to sight.) Pertaining to the sense 
 of sight, as the optic nerve. 
 
 Orbit. The bony hollow in which the eyeball rests. 
 
 Osmosis. (Greek, ua-fxSs, a thrusting or pushing.) The passage of 
 substances through animal membranes, and some other media, in 
 consequence of an obscurely understood power of selection in the 
 medium by which matters in solution and fluids are enabled to go 
 through in one direction rather than another, and some substances 
 to pass rather than others. By a skillful direction of this pro- 
 cess, matters in solution may be separated from each other. Osmosis 
 is constantly going on in the living body, and by its aid the nutri- 
 
340 
 
 GLOSSARY. 
 
 tive processes are carried on. The passage of matter through a mem- 
 brane into a vessel is called endosmosis, and the passage o\xt,exos7?iosis. 
 
 Ossifica'tion. (Latin, ossificatio, from os, a. bone, a.nd /acio, I make.) 
 The change of any substance into bone. 
 
 Oxida'tion. The chemical union of oxygen with any substance, 
 forming an oxide ; e. g., combustion is a rapid union of carbon and 
 oxygen, forming carbon dioxide. 
 
 Oxyhsemoglo'bin. (First part of the word oxygen, and haemoglobin, 
 q. V.) Haemoglobin loosely combined with oxygen. 
 
 Pan'creas. (Greek, irdyxpeas, the sweet-bread, from ttSj/, all, and Kp^as, 
 flesh.) The organ whose secretion, called the pancreatic juice, di- 
 gests fatty matters. Known to butchers as the sweet-bread. 
 
 Papil'la. (Latin, /«/z7/a, a nipple.) A minute projection from the 
 outer surface of the derma, containing the terminations of nerves 
 and blood-vessels. 
 
 Paraple'gia. (Greek, irapaTrXTjyla, paralysis.) Paralysis of the lower 
 part of the body on both sides. 
 
 Par'asite. (Greek, irapiairos, a table-companion.) Any living thing, 
 animal or vegetable, whose nature it is to attach itself to some other 
 living thing, and derive its nourishment from it. 
 
 Parot'id Glands. (Greek, irapwrldes, the parotid glands, from irapoi, 
 beside, and ovs, the ear.) The large salivary glands situated just 
 in front of the ears. 
 
 Pepsin. (Greek, Treirrw, to cook.) The organic constituent of the 
 gastric juice, one of the main agents in digestion. 
 
 Pericar'dium. (Greek, Trepi, around, and /capSta, the heart.) The 
 serous envelope of the heart, 
 
 Perios'teum. (Greek, Tepi, around, and ocrreov, a bone ) The mem- 
 brane, tough and fibroi:s, which envelops and clings closely to bone. 
 
 Peritonse'um. (Greek, rrepiTSpaiov, the peritonaeum, from irepi, around, 
 and TeiVw, to stretch.) The serous membrane which lines the ab- 
 dominal walls and envelops the organs contained in the cavity of 
 the abdomen. 
 
 Phantom Limbs. A term applied by medical men to the sensory 
 images produced by certain changes in the stumps of amputated 
 limbs, which are of such a nature that the persons appear to them= 
 selves to feel pain, tingling, or other sensations in that part of the 
 limb which has been separated from the body. 
 
 Phar'ynx. (Greek, (j)dpvy^, the throat.) That part of the throat which 
 can be seen through the open mouth, without the aid of instruments. 
 
 Physid'ogy. The science that describes the functions of the differ- 
 ent parts of living beings. 
 
GLOSSARY, 341 
 
 Pigment-Cells. {\.z.\.vn.,pigmentum,-^aimi.) Cells naturally contain- 
 ing coloring matter. 
 
 Plas'ma. (Greek, Trxdcrfxa, formed matter.) The fluid portion of the 
 blood before coagulation. 
 
 Pleu'ra. (Greek, TrAeupci, the pleura.) The serous membrane which 
 lines the chest and envelops the lungs. 
 
 Portal Vein, (Latin, /<?r/a, a gate.) The large vein which carries 
 the blood from the digestive organs to the liver. 
 
 Pro'teids. (Greek, irpwros, first.) A class of substances, e. g., albu- 
 men, fibrin, casein, etc., which contain carbon, hydrogen, oxygen, 
 nitrogen, and sulphur, whose molecules are veiy complex, and 
 which coagulate under proper conditions. So called because they 
 form the basis and the greater part of animal bodies. 
 
 Protoplasm. (Greek, irpuTos, first, and TrAac/ia, formed matter.) An 
 albuminous, somewhat jelly-like substance, which forms the princi- 
 pal part of living beings. It is very complex in structure, combin- 
 ing several of the proteids, probably with carbohydrates and fats. It 
 is the only matter in the world that presents the phenomena of life. 
 
 Pul'monary. (Latin, /z^/;«c, a lung.) Pertaining to a lung. 
 
 Pulmonary Artery. The blood-vessel that conveys blood from the 
 heart to the lungs. 
 
 Pulmonary Lobules. The smallest independent divisions of the 
 lungs, situated at the ends of the smallest bronchial tubes. 
 
 Pulmonary Veins. The blood-vessels that convey blood from the 
 lungs to the heart. 
 
 Pulmonary Vesicles. The minute subdivisions of the pulmonary 
 lobules. 
 
 Pulse. The blow given by an artery when suddenly distended. 
 Generally felt with the finger on the radial side of the wrist. 
 
 Pupil. The circular hole in the iris through which light enters the eye. 
 
 Pylorus. (Greek, irvKcapSs, a gate-keeper.) The opening by which 
 food passes from the stomach into the intestine. Also called the 
 pyloric orifice. 
 
 Ra'dial Artery. The artery lying on the radial or thumb side of the 
 fore-arm. 
 
 Reflex Action. Motor action of a nerve-center in response to a stim- 
 ulus without the co-operation of consciousness. 
 
 Retina. (Latin, retina^ the retina, from retc, a net, from the net-like 
 or mesh-like expansion of the optic nerve.) The internal nervous 
 coat of the eye, on which images of external objects must be formed 
 in order to make sight possible. 
 
 Rods and Cones. A term applied, on account of their shape, to ccr- 
 23 
 
342 GLOSSARY, 
 
 tain nervous structures in the outer layer of the retina farthest from 
 the light. They are packed side by side, like the seeds of a sun- 
 flower, and are believed to be the structures by which the ether- 
 waves are converted into a nerve-current, which, on reaching the 
 brain, gives us the sensation of light. 
 
 Sali'va. (Latin.) The spit or spittle, composed of fluids secreted by 
 the mouth. 
 
 Sal'ivary Glands. The glands that secrete the saliva. 
 
 Sarto'rius. (Latin, sartor, a tailor.) A long, ribbon-like muscle ex- 
 tending from the outer and upper part of the hip-bone to the leg, 
 just below and on the inner side of the knee. When it contracts it 
 raises the leg and turns it inward, as in crossing the legs. 
 
 Sciat'ic Nerve. (Contracted from ischiatic, Greek, jcrx'as, pain in 
 the leg.) The largest nerve of the lower limb, extending from the 
 pelvis to the foot at the back of the leg. 
 
 Sclerot'ic Coat. (Greek, a-KX-npSs, hard.) The outer coat of the eye, 
 consisting of white fibrous tissue. The white of the eye. 
 
 Seba'ceous Glands. (Latin, sebaceus, from sebujn, tallow.) Certain 
 glands in the skin, generally situated near the roots of hairs, secret- 
 ing a whitish, fatty, tallow-like substance, which tends to keep the 
 skin and hairs soft and pliable. 
 
 Semicircular Canals. A part of the internal ear filled with fluid, 
 and containing filaments of the auditory nerve. So called from 
 their shape. 
 
 Serous Membrane. A delicate kind of membrane secreting a small 
 amount of fluid, and lining all cavities in the body which do not 
 communicate with the external air, excepting the joints. 
 
 Se'rum. That fluid which remains after the clot has been separated 
 from coagulated blood. 
 
 Sewer-Air. A mixture of gases formed by the decomposition of 
 organic matters in sewers. Its most dangerous constituents are the 
 particles of solid matter and the living microscopic organisms that 
 float in it. 
 
 Spher'ical Aberration. The unequal refraction of light by a lens, 
 at different distances from its center, in consequence of which the 
 rays are not brought to the same focus, and the image is blurred 
 and indistinct. 
 
 Spinal Canal. The long cavity inside the backbone, in which the 
 spinal cord lies. 
 
 Spinal Cord. The long mass of nerve-substance that lies inside the 
 spine. 
 
 Spinal Nerves. The nerves that take their origin from the spinal cord. 
 
GLOSSARY. 343 
 
 Spine. The backbone. 
 
 Sprain. Rupture of a ligament, or of fibers thereof, by the sudden 
 twisting of a joint. 
 
 Stape'dius. (Latin, stapes, a stirrup.) A small muscle of the middle 
 ear. So called because it is connected with the stapes, one of the 
 bones of the ear. 
 
 Stria'tion. (Latin, strice, lines or markings.) The parallel m.arking 
 of voluntary muscular fibers at right angles to their length, only to 
 be seen with the microscope. 
 
 Styp'tics. (Greek, g-tvtttikSs, astringent.) Substances that produce 
 shrinking or contraction of living tissues. Astringents. 
 
 Su'tures. (Latin, sutiira, a seam.) The joints between the jagged 
 edges of the bones of the skull, which appear as if dove-tailed. 
 
 Sympathetic System. That portion of the nervous system that con- 
 trols the functions of organic life, i. e., the functions that are or 
 should be performed unconsciously. 
 
 Syno'vial Membrane. (Greek, avv, with, and Latin, oznuii, an egg.) 
 The membrane which lines the joints. So called because its 
 secretion, the synovial fluid, resembles the white of an egg. 
 
 System. Several different organs, of similar structure, spread through- 
 out the body, and performing similar functions. 
 
 Tape-worm. A worm whose larvae are introduced with the food, and 
 developed in the intestine. It is composed of many segments at- 
 tached to each other, and may grow to an enoiTnous length, twenty 
 or thirty feet. 
 
 Tendons. The fibrous cords by which the muscles are united with 
 the bones. 
 
 Thorac'ic Duct. The tube which collects the lymph from the lacteals 
 and most of the other lymphatic vessels, and discharges it into the 
 veins near the heart. 
 
 Tho'rax. (Greek, 0a>pa|, the chest.) The part of the trunk situated 
 above the diaphragm. The chest. 
 
 Tisoue. Two or more anatomical elements united so as to form one 
 structure. 
 
 Tra'cliea. (Greek, Tpaxe?a, rough.) The windpipe. 
 
 Trichi'na Spiralis. (Greek, Tplx"^os, made of hair, and Latin, 
 spiralis, spiral.) A parasitic worm often found in the flesh of the 
 hog, and sometimes introduced with raw ham or pork into the 
 human body, where it produces serious and even fatal disease. So 
 called because it is slender in form, and is usually seen coiled up 
 in a spiral. 
 Trigeminal Nerve. (Latin, trigeftiini, three of a kind.) The ner\'e 
 
344 
 
 GLOSSARY, 
 
 of sensation of the face. So called because there are three large 
 branches of it. 
 
 Tuber'cular Quadrigem'ina. (Latin, iubercula, small swellings, and 
 quadfigemina, four of a kind.) Certain protuberances, four in 
 number, near the base of the brain — the nerve-centers of vision. 
 
 Tym'panum. (Greek, TVfxiravop, a drum, or Latin, tympanum^ The 
 cavity of the middle ear. 
 
 Ulnar Artery. The artery lying on the inner or little-finger side of 
 the fore-arm. 
 
 U'rea. An excrementitious substance expelled from the body through 
 the kidneys. 
 
 Vaso-motor Nerves. (Latin, vasa, vessels.) Nerves which control 
 the movements of the muscles lying in the walls of the blood- 
 vessels. 
 
 Veins. Blood-vessels which convey blood toward the heart. 
 
 Ven'ae Ca'vae. (Latin, meaning the hollow veins) The large veins 
 which collect blood from the smaller ones and discharge it into the 
 heart. 
 
 Ven'tricles. (Latin, ventriculus, a little stomach.) The two largest 
 cavities of the heart, from which the blood is sent out into the 
 arteries. 
 
 Ver'tebra. (Latin, vertebra, a vertebra, from verto, I turn.) One of 
 the smaller bones of which the spine is composed. 
 
 Ver'tebral Arteries. Arteries which pass up into the head through 
 the vertebrae of the neck. 
 
 Vestibule. A part of the internal ear. 
 
 Villi. (Latin, meaning closely-set hairs.) Minute projections from 
 the internal surface of the small intestine, containing blood-vessels 
 and lacteals, by which the nutritious portions of the food are ab- 
 sorbed. 
 
 Vital Knot. A portion of the medulla oblongata (q. v.), the destruc- 
 tion of which kills instantly. 
 
 Vit'reous Humor. (Latin, vitrezts, glassy.) A transparent, jelly-like 
 mass filling the space in the eyeball between the lens and the retina. 
 
 Vocal Chords. Two pearly-white, glistening, fibrous bands at the 
 upper part of the larynx, whose vibration causes the voice. The 
 opening between them is the glottis (q. v.). 
 
 Voluntary Muscles. Muscles that are under control of the will. 
 
 White Matter. A kind of nervous tissue composed mainly of fibers, 
 and serving to conduct nerve-force, but not to originate it. 
 
INDEX. 
 
 Abercrombie, 223. 
 Aberration, chromatic, 302. 
 
 spherical, 302. 
 Absinthe, 245. 
 
 Abuse of nervous system, 239. 
 Accommodation, function of, 299. 
 Adam's apple, 309. 
 Air, amount respired with each 
 breath, 127. 
 
 amount respired daily, 129. 
 
 changed by respiration, 130. 
 
 composition of, 130, 133. 
 
 contamination of, 130, 131, 136. 
 
 impure in houses, 136. 
 
 purification of, by plants, 135. 
 
 watery vapor in, 134. 
 Albinos, eyes of, 296. 
 Albumen of blood, 114. 
 
 of food, 51. 
 Alcohol, definition, 3. 
 
 properties, 3. 
 
 general effects of, 10, 30, 44, 58, 
 109. 
 
 on the muscles, 45. 
 
 effect on eyes, 307. 
 
 effect on stomach, 89, 90. 
 
 on the liver, 108. 
 
 on the blood, 117. 
 
 on the throat, 123. 
 
 on the lungs, 123. 
 
 on respiration, 133. 
 
 on the heart, 157. 
 
 on the blood-vessels, 168. 
 
 on the nervous system, 239, 240, 
 241. 
 
 on the temperature, 263. 
 
 on endurance, 45, 264. 
 
 hereditary effects of, 244. 
 
 Alcoholic beverages, 56. 
 
 origin and nature of, 54. 
 Ale, 57- 
 Alimentary canal, 72. 
 
 muscles of, 74. 
 Anatomical element defined, I. 
 Anatomy defined, i. 
 Aneurism, 169. 
 Animal heat, 258. 
 
 cause of, 260. 
 
 theories of, 259. 
 Anterior nerve-root, division of 
 
 211. 
 Aorta, 151, 170. 
 Apoplexy, 170, 214. 
 Apparatus defined, 2. 
 Appendix vermiformis, 97. 
 Aqueous humor, 295. 
 Aroma, 278. 
 Arteries, 159. 
 
 compression of large, 186. 
 
 rapidity of current in, 165. 
 
 structure of, 159. 
 
 behavior of, when cut, 180. 
 Artery, brachial, 171. 
 
 carotid, 172. 
 
 femoral, 171. 
 
 formation of clot in, 183. 
 
 pulmonary, 166, 174. 
 
 radial, 172. 
 
 ulnar, 172. 
 
 venous blood in, 166. 
 
 vertebral, 172. 
 Artificial respiration, 143. 
 Asphyxia, 141. 
 Asthma, 124. 
 Auditory nerve, 286. 
 Auricles, 149. 
 
346 
 
 INDEX. 
 
 Automatic actions, 2i8, 
 Axis-cylinder, 192. 
 
 Bacteria, 139. 
 Banting system, 51, 
 Bath, effect of cold, 268. 
 
 waiTn, 269. 
 Bathing, rules for, 269. 
 Beaumont, 79. 
 Bell, Sir Charles, 211. 
 Bernard, Claude, 70. 
 Biceps, disadvantageous action of, 
 
 37. 
 Bile, 100, 
 
 function of, loi, 102. 
 Black-heads, 257. 
 Bleeding. (See Hgemorrhage.) 
 Blind spot of eye, 297. 
 Blood, 112. 
 
 albumen of, T14. 
 
 total amount of, 116. 
 
 changes of, during digestion, 
 107. 
 
 changes of, during respiration, 
 
 131- 
 
 coagulation of, 115, 116, 179. 
 
 distribution of, 168. 
 
 fibrin of, 114. 
 
 oxygen in, 116. 
 
 plasma of, 114. 
 
 rapidity of, 165. 
 
 serum of, 115, 
 
 varying color of, 117. 
 Blood-corpuscles, function of, 132. 
 
 red, 112. 
 
 w^hite, 114. 
 Blood-vessels, 159. 
 
 communicating, 164. 
 
 diseases caused by alcohol, 169. 
 Blushing, 203. 
 Body, effect of cold on, 261. 
 
 effect of heat on, 262. 
 
 minute structure of, 5. 
 
 temperature of, 260. 
 
 temperature of, how regulated, 
 262. 
 Bone at different ages, 12. 
 
 composition of, 11, 
 
 minute structure of, 15. 
 
 living and dead, 11. 
 
 renewal of, 15. 
 
 extremities and shaft of, 13. 
 
 Bones, injuries of, 27. 
 
 number of, 17. 
 
 of ear, 285. 
 
 ossification of, 17. 
 
 uses of, II. 
 
 varieties of, 13. 
 Brachial artery, 171. 
 Brain, 219. 
 
 convolutions of, 221. 
 
 disease of, 224. 
 
 hemispheres of, 221. 
 
 importance of exercising, 236. 
 
 injuries of, 224, 
 
 over-exercise of, 237. 
 
 size of, 223. 
 
 smaller ganglia of, 226. 
 
 softening of, 224. 
 Brandy, 63. 
 
 Breath, organic matter of, 13X1 
 136. 
 
 shortness of, 177, 188. 
 Bronchi, 119. 
 
 Caecum, 97. 
 Callous skin, 258. 
 Calvin Edson, 106. 
 Capillaries, 160. 
 
 pressure in, 164. 
 
 rapidity of current in, 165. 
 
 size of, i6t. 
 Caramel, 57, 64. 
 
 Carbon dioxide, theories about, 
 130. 
 
 where formed, 132. 
 Carbonaceous foods, 49. 
 Cardiac orifice of stomach, 77. 
 Care of injured persoas, 29. 
 Carotid artery, 172. 
 Cartilage, 25. 
 Cartilages of trachea, 119. 
 Casein, 51. 
 Cauda equina, 208. 
 Cell, 6. 
 Cells, division of, 8. 
 
 epidermal, 74. 
 
 epithelial, 74. 
 
 growth of, 8. 
 
 living and dead, 7. 
 
 nerve, 192. 
 
 selection by, 9. 
 
 size of, 7. 
 
 vicarious action of, 10. 
 
INDEX. 
 
 347 
 
 Cerebellum, diseases of, 226. 
 function of, 226. 
 size of, 225. 
 structure of, 225. 
 Cerebro-spinal system, 191. 
 Cerebrum, 219. 
 
 function of, 222, 224. 
 size of, 222, 223. 
 structure of, 220. 
 Chabert, 266. 
 Chapped hands, 270. 
 Chest, natural shape of, 23. 
 Chloral, 4, 250. 
 Chloroform, 4, 249. 
 Choroid coat, 294. 
 function of, 29&. 
 Chromatic aberration, 302. 
 Chronic alcoholism, 242. 
 Chyle, 107. 
 Chyme, 96. 
 Cider, 60. 
 Cilia, 122. 
 
 action of, 129. 
 Ciliary muscle, 299. 
 Ciliated epithelium, 122. 
 Circulation, 146, 151. 
 disorders of, 175. 
 general, 151. 
 obstruction of, 175. 
 pulmonar}', 148. 
 rapidity of, 167. 
 Cirrhosis, log. 
 Clot, 115. 
 Clothing, 272. 
 Coagulation of blood, US- 
 conditions of, 179. 
 Cochlea, 286. 
 Coffee, 89. 
 
 Cold arrests bleeding, iSl. 
 bath, effect of, 268. 
 effect of. on body, 261. 
 Colds, cause of, 206. 
 
 in the head, danger of, 2S9. 
 Color-blindness, 303. 
 Combustion, pollution of air 
 
 136. 
 Complexion, 254. 
 Compress, graduated, 187. 
 Compression of wounds, 182. 
 Condiments, 87. 
 Confectioner)', 94. 
 Connective tissue, 32. 
 
 by, 
 
 Contagious diseases, 138. 
 Convolutions of brain, 221. 
 Cooking, 53. 
 
 Co-ordination, organs of, 189. 
 Cornea, function of, 296. 
 
 structure of, 293. 
 Corns, 258. 
 Cr>'ing, 306. 
 Crystalline lens, 295. 
 
 function of, 29S. 
 Curvature of spine, 41. 
 Cuticle, cutis, 252. 
 Cuvier, 223. 
 Cysticercus cellulosse, 95. 
 
 Dandruff, 271. 
 
 Deafness, frequent cause of, 290. 
 Deception by the senses, 275. 
 Delirium tremens, 243. 
 Derma, 253. 
 Diaphragm, 125. 
 Diffusion of gases, 128. 
 Digestion, blood during, 107. 
 intestinal, 96. 
 ner\-ous control of, 205. 
 stomach, 72, 78. 
 time required for, 87. 
 
 Digestive apparatus, 65. 
 
 Disinfectants, 139. 
 
 Dislocations, 28, 29. 
 
 Dissipation, 239. 
 
 Distillation, 62, 63. 
 
 Draughts, 137, 2Ci, 206. 
 
 Drink, 88. 
 
 Dropsy, 176, 177. 
 
 Drowned, resuscitation of the, 142 
 
 Drowning, 142. 
 
 Drum of ear, 284. 
 
 Duodenum, 98. 
 
 Dupuytren, 223. 
 
 Ear, bones of. 2S5. 
 
 care of, 289. 
 
 drum of, 284. 
 
 external, 283. 
 
 insects in, 289. 
 
 internal, 2S6. 
 
 middle, 284. 
 
 muscles of, 2S4. 
 Ear-scoops, 289. 
 Ear-wax, 2:9. 
 Eating, rules for, 84-87, 95. 
 
348 
 
 INDEX. 
 
 Education, 234. 
 Effervescent drinks, 61. 
 Element, anatomical, i. 
 Emotion, effects of, 203. 
 Epidermal cells, 74, 
 Epidermis, 74, 252, 254. 
 Epiglottis, 121, 309. 
 Epithelium, 74. 
 
 ciliated, 122. 
 Ether, the, 291. 
 Eustachian tube, 285. 
 
 inflammation of, 290. 
 Exercise, 42. 
 
 of nei-vous system, 236, 237. 
 
 rules for, 44. 
 Exhaustion, danger of, 43. 
 Expiration, force of, 127. 
 
 mechanism of, 126. 
 External auditory canal, 284, 
 External ear, 283. 
 Extremities, wounds of, 185. 
 Eye, blind spot of, 297. 
 
 situation of, 292. 
 Eyeball, muscles of, 304. 
 
 structure of, 292. 
 Eyebrows, lashes, lids, 305. 
 Eyes, care of, 307. 
 
 opening of, under water, 308. 
 
 straining of, 308. 
 
 Face, washing of, 270. 
 Facial nerve, 232. 
 Fainting, 187. 
 Far-sight, 304, 
 Fat, 50. 
 
 craving for, in winter, 261. 
 Fatigue, 40. 
 Femoral artery, 171. 
 Fermentation, 54, 55. 
 Fiber, 5. 
 Fibrin of blood, 114. 
 
 of food, 51. 
 Fibrous tissue, 5, 73. 
 Fire-king, 266. 
 Fireplace as ventilator, 137. 
 Fluid, synovial, 26. 
 Follicles, hair, 256, 
 Food, absorption of, 103. 
 
 carbonaceous, 49. 
 
 choice of, 87. 
 
 classification of, 47. 
 
 daily amount of, 53. 
 
 Food, inorganic elements of, 48c 
 
 necessity of, 46. 
 
 nitrogenous, 51. 
 
 non-nitrogenous, 49. 
 
 parasites in, 94. 
 
 variety of, 52. 
 Fracture, green-stick, 13. 
 
 results of, 28. 
 Fractures, 27. 
 
 healing of, 2g. 
 Freezing, 260, 262. 
 Frog's foot, circulation in, 1650 
 Frontal sinuses, 22. 
 Function defined, 2. 
 Fusel-oil, 245. 
 
 Ganglia, nervous, 193. 
 
 sympathetic, 200. 
 Gangrene, 179. 
 Garotte, 230. 
 Gases, diffusion of, 128. 
 Gastric juice, amount of, 81. 
 
 composition of, 81. 
 
 secretion of, 80. 
 General circulation, 148. 
 Gin, 63. 
 Glands, lachrymal, 305. 
 
 lymphatic, 105. 
 
 nervous supply of, 203. 
 
 salivary, 69. 
 
 sebaceous, 256. 
 
 sweat, 257. 
 Glottis, 120, 309. 
 Glucose, 50. 
 
 Graduated compress, 187. 
 Granular matter, 7. 
 Gray matter, function of, 196, 
 
 structure of, 192. 
 Great pouch of stomach, 77. 
 Green-stick fracture, 13. 
 Gymnastics, 42. 
 
 Habits, formation of, 235. 
 Hsemoglobin, 132. 
 Haemorrhage, 180. 
 
 artificial arrest of, 181. 
 
 compression for, 182. 
 
 natural arrest of, 180. 
 
 permanent arrest of, 183. 
 Hair, 259. 
 
 cutting of, 272. 
 Handkerchief, knotted, i86c 
 
INDEX. 
 
 349 
 
 Hands, chapping of, 270. 
 
 washing of, 270. 
 Hang-nails, 272. 
 Hausmann, 223. 
 Hearing, sense of, 283. 
 Heart, 147. 
 
 blood-vesselsconnected\vith,i5i. 
 
 cavities of, 148. 
 
 contraction of, 154. 
 
 disease of, 176. 
 
 nervous supply of, 155. 
 
 rapidity of contraction of, 156. 
 
 sounds of, 155. 
 
 two sides of, 148. 
 
 valves of, 149. 
 
 voluntary arrest of, 156. 
 Heart-disease, detection of, 179 
 Heat, effect of, on body, 262. 
 
 exposure to dry, 266. 
 
 exposure to moist, 266. 
 Hemispheres of brain, 221. 
 Hiccough, 126. 
 Homologous bones, 25. 
 Humor, aqueous, 295. 
 
 vitreous, 294. 
 Hunger, 85. 
 Hygiene defined, I. 
 
 Impure air, 136. 
 Inactivity, muscular, 41. 
 Indigestion, 82, 86. 
 Injured persons, care of, 29. 
 Injuries of bones and joints, 27. 
 Inorganic elements of food, 48. 
 Insects in the ear. 2S9. 
 Insensible perspiration, 265. 
 Inspiration, force of, 127. 
 
 mechanism of, 125. 
 Internal ear, 286. 
 Intestinal digestion, 96. 
 
 juices, 102. 
 
 villi, 104. 
 Intestine, large, 97. 
 
 muscles of, 97. 
 
 small, 96. 
 Intoxication, 240, 241. 
 Involuntary muscles, 34. 
 Iris, 295. 
 
 color of, 301. 
 
 function of, 301. 
 
 nervous supply of, 201. 
 Irritability, muscular, 38. 
 
 Jaundice, lOI. 
 
 Joints, 25. 
 
 injuries of, 28. 
 Jugular veins, 173. 
 Juice, gastric, 81. 
 
 intestinal, 102. 
 
 pancreatic, 99. 
 
 Knotted handkerchief, use of, 186, 
 Koumyss, 60. 
 
 Labyrinth, 286. 
 Lachrymal gland, 305. 
 Lacteals, 103, 105-107. 
 Lager-beer, 57. 
 Large intestine, 97. 
 Larynx, 119, 309. 
 
 abuse of, 311. 
 
 care of, 312. 
 
 movable cartilages of, 310. 
 Ladssimus dorsi, 36. 
 Laudanum, 3. 
 Lavoisier, 259. 
 Lead in candy, 94. 
 Lens, 295. 
 
 function of, 298. 
 
 varying shape of, 300, 
 Liebig, 259. 
 Ligaments, 26. 
 Ligatures, use of, 184. 
 Light, 291. 
 
 Limbs, number of bones in, 24. 
 Limit of distinct vision, 300. 
 Liver, 99. 
 Liver-sugar, 99. 
 Living skeleton, 106. 
 Lungs, 121. 
 
 blood-vessels of, 124. 
 
 change of air in, 12S. 
 
 minute structure of, 122, 
 
 serous membrane of, 124. 
 Lymph, 105, 165. 
 Lymphatic glands, 105. 
 
 Magendie, 211. 
 Malarial fevers, 138. 
 Malt, 57. 
 
 liquors, 56, 57. 
 Maltose, 57. 
 Marrow, 14. 
 Masseter muscle, 68. 
 Mastication, 68, 70, 84. 
 
350 
 
 INDEX. 
 
 Medulla oblongata, 227. 
 
 automatic action of, 229. 
 Membrane, mucous, 72. 
 
 serous, 75. 
 Membrane, synovial, 26. 
 Microscopic organisms, 59, 60, 95, 
 
 138. 
 Middle ear, 284. 
 Mineral v/aters, 61. 
 Minute structure of body, 5. 
 Morphia, 2, 91. 
 
 Mouth, watering of the, 70, 203. 
 Mucous membrane, 72. 
 Mumps, 6g. 
 Muscae volitantes, 294, 
 Muscle, ciliary, 299. 
 
 minute structure of, 34. 
 Muscles, 32. 
 
 contraction of, 35. 
 
 of eyeball, 304. 
 
 function of, 32. 
 
 involuntary, 34. 
 
 size of, 36. 
 
 voluntary, 32. 
 Muscular contraction, force of, 37. 
 
 contraction, sound of, 68. 
 
 contraction, waste during, 40. 
 
 inactivity, 41. 
 
 irritability, 38. 
 
 overwork, 40. 
 
 sense, 38, 39. 
 
 strength, feats of, 43. 
 Mustard, 88. 
 Myelin, 192. 
 
 Nails, 255. 
 
 care of, 272. 
 Narcotic poisons, 2, 250. 
 Nasal passages, 118. 
 Near-sight, 304. 
 Nerve, auditory, 286. 
 
 division of anterior root of, 211. 
 
 division of posterior root of, 
 212. 
 
 effect of dividing, 210. 
 
 facial, 232. 
 
 olfactory, 280. 
 
 optic, 297. 
 
 sciatic, 233. 
 
 trigeminal, 231. 
 Nerve-cells, 192. 
 Nerve-centers, 193. 
 
 Nerve-current, nature of, 194, 197. 
 
 rapidity of, 195. 
 Nerve-fibers, 191. 
 
 function of, 193, 194. 
 Nerves, electrical current in, 194, 
 197. 
 
 exhaustion of, 196. 
 
 sensations referred to extremity 
 of, 215. 
 
 structure of, 193. 
 
 vaso-motor, 168, 204. 
 Nervous system, abuse of, 239. 
 
 divisions of, 189. 
 
 education of, 234. 
 Nervous tissue, 191. 
 Nicotine, 3, 4. 
 Nitrogenous foods, 51. 
 Non-nitrogenous foods, 49. 
 Nose, structure of, 118. 
 Nucleolus, 7. 
 Nucleus, 7. 
 Nystagmus, 296, 
 
 QEsophagus, 72, 75. 
 
 Olfactory nerve, 280. 
 
 Opium, origin and properties, 2. 
 
 effect on the young, 31. 
 
 effect on the stomach, 91, 94. 
 
 effect on respiration, 133. 
 
 effect on nervous system, 247- 
 249. 
 Optic nerve, 297. 
 Optic nerves, origin of, 227. 
 Orbit of eye, 292. 
 Organ, defined, 2. 
 Organ of speech, 309. 
 Organic matter of breath, 131, 
 
 136. 
 Organisms, microscopic, 59, 60, 
 
 95, 138. 
 Organs of co-ordination, 189. 
 
 of motion, ii. 
 
 of perception, 274. 
 
 of protection, 252. 
 
 of repair, 46. 
 Ossification of bones, 17. 
 Out-door sports, 42. 
 Overeating, 84. 
 Over-exercise of brain, 237. 
 Overv/ork, muscular, 40. 
 Oxygen, necessity of, 116. 
 Oxyhaemoglobin, 132. 
 
INDEX. 
 
 351 
 
 Pancreas, 98. 
 
 functions of, gg. 
 Pancreatic juice, gg. 
 Papillae of skin, 254, 
 
 structure of, 274. 
 Paraplegia, 217. 
 Parasites in food, g4. 
 Paregoric, 3. 
 Parotid glands, 6g. 
 Pepper, 88. 
 Pepsin, 81. 
 
 Perception, organs of, 274. 
 Pericardium, 147. 
 Periosteum, 14. 
 
 uses of, 14. 
 Peritonaeum, 103. 
 Perry, 60. 
 
 Perspiration, amount of, 265. 
 Perspiratory glands, 257. 
 Phantom limbs, 215. 
 Pharynx, 75. 
 Physiology defined, I. 
 Pigment-cells, 254. 
 Plain food, advantages of, 86. 
 Plants, respiration of, 135. 
 Plasma, 114. 
 Pleura, 125. 
 Pleurisy, 125. 
 Poison, defined, 2. 
 Portal vein, 106, 173. 
 Porter, 57. 
 Posterior nerve-root, division of, 
 
 212. 
 Protection, organs of, 252. 
 Proteids, 51. 
 Protoplasm, 6, 7. 
 Proud flesh, g. 
 Pulmonary artery, 166, 174. 
 
 circulation, 148. 
 
 lobule, 122. 
 
 veins, 166, 174. 
 
 vesicle, 122. 
 Pulse, cause of, 159. 
 
 rapidity of, 156. 
 
 situation of, 160. 
 
 voluntary control of, 156. 
 Pupil, contraction of, 201, 
 Pylorus, 77. 
 
 Radial artery, 172. 
 
 Red blood-corpuscles, 112. 
 
 Reflex action, igs, 216, 233. 
 
 Respiration, 118. 
 
 artificial, 143. 
 Rest for muscles, 43. 
 Resuscitation of the drowned, 142 
 Retina, 2g4. 
 
 eff"ect of shocks on, 302. 
 
 persistence of impressions oi'i 
 303- 
 
 structure of, 297. 
 Ribs, 22. 
 
 cartilages of, 23. 
 
 motion of, 23. 
 Rods and cones of retina, 2g7. 
 Root-beer, 5g, 61, 
 Roots of spinal nerves, 211. 
 Rules for bathing, 269. 
 
 for dress, 273. 
 
 for eating, 84-87, 95. 
 
 for exercise, 44. 
 
 for entering sick-room, 140. 
 Rum, 63. 
 
 St. Martin, 79. 
 Saliva, 68. 
 
 amount of, 71. 
 
 use of, 70. 
 Salivary glands, 69. 
 Salt, 48. 
 Sartorius, 36. 
 
 Savages, acute senses of, 281. 
 Scalp, care of, 271. 
 Schwann, white substance of, 192. 
 Sciatic nerve, 233. 
 Sclerotic coat, 292. 
 
 function of, 295. 
 Sebaceous glands, 256. 
 Semicircular canals, 286-288. 
 Sensation, 195. 
 
 divisions of, 209. 
 Sense, muscular, 38. 
 
 of hearing, 2S3. 
 
 of sight, 291. 
 
 of smell, 2S0. 
 
 of taste, 277. 
 
 of touch, 274. 
 Senses, deception by, 275. 
 Serous membrane, 75. 
 Serum of blood, 115. 
 Sewer-air, 139. 
 Shoes, 273. 
 
 Shortness of breath, 177, 188. 
 Sick-room, rules on entering, 14a 
 
352 
 
 INDEX. 
 
 Sight, sense of, 2gi. 
 Sinuses, frontal, 22. 
 Skin, absorption through, 267. 
 
 effects of pressure on, 258. 
 Skin, impurities on, 268. 
 
 respiration through, 267. 
 
 structure of, 252. 
 Skull, 20, 21. 
 Sleep, 237. 
 Small-beer, 59, 61. 
 Small intestine, 96. 
 Smell, sense of, 280. 
 
 use of, 67, 282. 
 Sniffing, 281. 
 Soap, 270, 271. 
 Soda-water, 55, 61. 
 Solar plexus, 200. 
 Sound, determination of source of, 
 287. 
 
 qualities of, 287. 
 Sounds of heart, 155. 
 Special senses, 276. 
 Speech, organ of, 309. 
 Spherical aberration, 302. 
 Spinal canal, 19. 
 Spinal cord, 208. 
 
 crossing of fibers in, 214. 
 
 diseases of, 217. 
 
 reflex action of, 216. 
 Spinal nerves, 209. 
 
 roots of, 211. 
 
 two kinds of fibers of, 213. 
 Spine, 19. 
 
 cartilages of, 17, 20. 
 
 curvature of, 41. 
 
 mobility of, 19. 
 Spleen, no. 
 
 function of, iir. 
 Splints, 30. 
 Sprains, 29. 
 Stapedius, 36. 
 Starch, 49. 
 
 Stomach, appearance of, during 
 indigestion, 82. 
 
 foods digested in, 78. 
 
 interior of, 80. 
 
 movements of, 81. 
 
 structure of, 75. 
 Stomach-digestion, 72, 78. 
 
 time of, 83. 
 Stout, 57. 
 Strength, muscular, 43. 
 
 Striation, 34. 
 Styptics, 181. 
 Suffocation, 141. 
 Sugar, 50. 
 Sunstroke, 261. 
 Sutures, 21. 
 Swallowing, 75. 
 Sweat-glands, 257. 
 Sweet-bread, 98. 
 Sympathetic ganglia, 200, 
 Sympathetic nerves, division of, 
 202. 
 
 peculiarity of, 197. 
 
 sluggish action of, 200. 
 Sympathetic system, 191, 199. 
 
 effect of cold on, 205. 
 
 exhaustion of, 206. 
 Synovial fluid, 26. 
 
 membrane, 26. 
 System defined, 2. 
 
 Tape-worm, 95. 
 
 Taste, modifications of, 277. 
 
 peculiarities of, 278. 
 
 sense of, 276, 277. 
 
 use of, in eating, 67. 
 Tea, 89. 
 Tears, 305. 
 Teeth, 67. 
 
 care of, 71. 
 Temperature of body, 260. 
 
 how regulated, 262. 
 Tendons, 36. 
 Thoracic duct, 106. 
 Tight lacing, effect of, 24. 
 Tissue, connective, 32. 
 
 defined, I. 
 
 fibrous, 5. 
 Tobacco, origin and properties, 3. 
 
 general effect of, 10, 30, 92. 
 
 effect on digestive organs. 92, 
 
 93- 
 
 effect on the blood, 117. 
 
 effect on the throat, 123. 
 
 effect on the heart, 158. 
 
 effect on nervous system, 2450 
 
 effect on the eyes, 307. 
 Toilet-soaps, 271. 
 Tongue, nerves of, 276. 
 Touch, delicacy of, 275. 
 
 sense of, 274. 
 Townsend, Colonel, 157. 
 
INDEX. 
 
 353 
 
 Trachea, 119. 
 
 Trichina spiralis, 94. 
 Trigeminal nerve, 231. 
 Tubercula quadrigemina, 227. 
 Tympanum, 285. 
 
 Ulnar artery, 172. 
 nerve, 215. 
 
 Valves of heart, 149. 
 
 of heart, peculiar, 152, 
 
 of veins, 162. 
 Vaso-motor nerves, 16S, 204. 
 Vein, arterial blood in, 166. 
 
 behavior of, v.'hen cut, iSo. 
 
 portal, 106. 
 Veins, 161. 
 
 circulation in, 162. 
 
 jugular, 173. 
 
 pulmonary, 166, 174. 
 
 rapidity of current in, 166. 
 
 structure of, i6i. 
 
 valves of, 162. 
 Venae cavae, 173. 
 Ventilation, 136. 
 Ventricles, 149. 
 Ventriloquism, 2S8. 
 Vertebra, 17. 
 Vertebral artery, 172. 
 Vestibule, 2S6. 
 Villi, 104. 
 
 pumping action of, 107. 
 
 Vinegar, 55. 
 
 Vision, limit of distinct, 300. 
 Vital knot, 228, 229. 
 Vitreous humor, 294. 
 Vocal chords, 1 2 1, 309. 
 
 congestion of, 311. 
 Voice, breaking of, 312. 
 
 modulation of, 311, 
 
 production of, 310, 
 Voluntary muscles, 32. 
 
 Warm bath, effect of, 269. 
 Warts, 258. 
 
 Washing hands and face, 270. 
 Waste during muscular contract 
 
 tion, 40. 
 Water, 4S. 
 
 paramount necessity of, 52. 
 Wave theory of light, 291. 
 Weeping, 306. 
 Weiss-beer, 57. 
 Whisky, 63, 
 
 White blood-corpuscles, 114. 
 White matter, 191. 
 
 function of, 194. 
 W^indpipe, 119. 
 Wine, 59, 60. 
 Wort, 57. 
 W^ounds, compression of, i82o 
 
 of extremities, 1S5. 
 
 healing of, 9. 
 
 THE END. 
 
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 tian Temperance Union, and each book bears the ofticial indorsement 
 of the Union. 
 
 « 
 Copies of the above books luill be mailed^ postpaid, on receipt of p} ice. 
 Full price-list will be sent on application. Correspondence is cordially 
 invited. 
 
 AMERICAN BOOK COMPANY. 
 
 NEW YORK .-. CINCINNATI .-. CHICAGO. 
 
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PUBLICATIONS OF THE AMERICAN BOOK COMPANY. 
 
 General Science. 
 
 Doerner's Treasury of Knowledge. 
 
 By celia doerner. | ^^J jJ; ;'.;;;;;; ; ; ^°tt 
 
 This book is designed to fill a gap in the ordinary course of instruction, and fur- 
 nishes in a small compass much useful and important information. Since it combines 
 entertainment with instruction, it will be found especially useful to parents as an addi- 
 tion to the child's home library. 
 
 Hooker's Child's Book of Nature. (Complete.) 
 
 By WORTHINGTON HOOKER, M, D., $I.OO. 
 
 Three parts in one : Part I. Plants; Part II. Animals; Part III. Air, Water, 
 Heat, Light, etc. Designed to aid mothers and teachers in training children in the 
 observation of Nature. It presents a general survey of the kingdom of Nature in a 
 manner calculated to attract the attention of the child, and at the same time to furnish 
 him with accurate and important scientific information, 
 
 Monteith's Easy Lessons in Popular Science. 
 
 By James Monteith $0,75. 
 
 This book combines the conversational, catechetical, blackboard, and object 
 plans, with maps, illustrations, and lessons in drawing, spelling, and composition. The 
 subjects are presented in a simple and effective style, such as would be adopted by a 
 good teacher on an excursion with a class. 
 
 Monteith's Popular Science Reader. 
 
 By James Monteith $0.75. 
 
 This contains lessons and selections in Natural Philosophy, Botany, and Natural 
 History, with blackboard, drawing, and written exercises. It is illustrated with many 
 fine cuts, and brief notes at the foot of each page add greatly to its value. 
 
 Steele's Manual. (Key to Fourteen Weeks' Course.) 
 
 By J. DoRMAN Steele, Ph. D $i.co. 
 
 This is a manual of science for teachers, containing answers to the practical ques- 
 tions and problems in the author's scientific text-books. It also contains many valuable 
 hints to teachers, minor tables, etc. 
 
 Wells's Science of Common Things. 
 
 By David A. Wells, A. M $0.85. 
 
 This is a familiar explanation of the first principles of physical science for schools, 
 families, and young students. Illustrated with numerous engravings. It is designed 
 to furnish for the use of schools and young students an elementary text-book on the 
 first principles of science. 
 
 Copies mailed, post-paid, on receipt of price. Full price-list sent on application. 
 
 AMERICAN BOOK COMPANY, 
 
 NEW YORK .1- CINCINNATI .:• CHICAGO. 
 
 1*70} 
 
DATE DUE 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 Printed 
 in USA 
 
COLUMBIA UNIVERSITY 
 
 0032108575