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Columbia ^Snt&ersitg %tttmz& 
 
 SCIENTIFIC FEATURES OF MODERN 
 MEDICINE 
 
 THE JESUP LECTURES 
 1911 
 
COLUMBIA 
 
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COLUMBIA UmVEBSITT LECTURES 
 
 SCIENTIFIC FEATUEES OF MODEEN 
 MEDICINE 
 
 BY 
 
 FREDERIC Sf^LEE, Ph.D. 
 
 DALTON PROFESSOR OF PHYSIOLOGY, COLUMBIA UNIVERSITY 
 
 -ma 
 
 THE COLUMBIA UNIVERSITY PRESS 
 1911 
 
 All rights reserved 
 

 COFTBISHT, 1911, 
 
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 Set up and electrot3rped. Published November, 191X. 
 
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PREFACE 
 
 An appointment to the lectureship founded by an appre- 
 ciative .and generous patron of science, the late Morris K. 
 Jesup, Es4., has given me an opportunity to present some of 
 the striking features of modern medicine which illustrate its 
 genuinely scientific character, its great ctange from the medi- 
 cine of the past, and its hopeful outlook for the future. 
 Obviously no attempt could here be made to survey its whole 
 field; but I have endeavored, through a consideration of 
 selected topics, to depict its spirit. Human beings may be 
 divided into those who do, and those who do not, believe 
 in the efficiency of medicine. The relative number of non- 
 believers has always been small, and is doubtless much less 
 now than in the days of the Greeks and of Moli^re, but their 
 sentiments have ever been loudly proclaimed. It is hoped 
 that these pages may be read by both classes. They may 
 perchance help to fortify the believers, and, if not actually 
 to convert the dissenters, at least to make their doubts appear 
 less rational. The labors of a learned profession can easily 
 be belittled by those who are less learned. I shall be gratified 
 if what I have here written shall be instrumental in inducing 
 laymen to study the human body and appreciate what men 
 of medicine are now doing to maintain health and to prevent, 
 diagnose, treat, and cure disease. When laymen do this, the 
 influence of medical cults and healing sects is sure to decline. 
 
 The lectures here published were delivered at the American 
 Museum of Natural History in the city of New York during 
 the months of February and March, 1911. As with previous 
 lectures on the same foundation, the endeavor has been to 
 present the subject matter clear-cut and in language that is 
 
Vi PREFACE 
 
 not too technical for the intelligent layman. The latter 
 is often eager to learn, but cannot be criticised if he finds the 
 literature of science written in words that are foreign to his 
 mother tongue. In a few cases I have taken the liberty of 
 quoting from previous writings of my own, without acknowl- 
 edging the repetition of my language. It has been found 
 impracticable to reproduce the many illustrations that were 
 helpful in the oral presentation of the lectures. 
 
 My thanks are due to my colleagues, Professors Francis 
 Carter Wood and Phillip Hanson Hiss, and Drs. W. A. Bas- 
 tedo and H. H. Janeway, and to other friends, Drs. Simon 
 Flexner, William Hallock Park, James Ewing, Alexis Carrel, 
 Nathan W. Green, and Major F. F. Russell. Several of these 
 friends have read critically portions of my manuscript and 
 have ofEered helpful suggestions. 
 
 FREDERIC S. LEE. 
 Columbia TJhivbrsitt, 
 
 October 1, 1911. 
 
CONTENTS 
 
 Pass 
 
 I. A Sketch of the Normal Human Bodt . . 1 
 
 II. The Nature of Disease. Methods of Diagnos- 
 ing Disease 22 
 
 in. Methods of Treating Disease .... 42 
 
 rV. Bacteria and Protozoa and their Kelation to 
 
 Disease 64 
 
 V. The Treatment and the Prevention of Infec- 
 tious Diseases 86 
 
 VI. The Problem of Cancer and other Problems . 110 
 
 Vn. Features of Modern Surgery 132 
 
 Vm. The BdLE of Experiment in Medicine. The 
 
 Public and the Medical Profession . . . 154 
 
 Index 177 
 
SCIENTIFIC FEATURES OF MODERN 
 MEDICINE 
 
 I 
 
 A SKETCH OF THE NORMAL HUMAN BODY 
 
 In his profound book, "Of the Proficience and Advance- 
 ment of Learning," Francis Bacon, writing at the beginning 
 of the seventeenth century, speaks of medicine as follows : 
 "Medicine is a science which hath been . . . more professed 
 than laboured, and yet more laboured than advanced ; the 
 labour having been, in my judgement, rather in circle than 
 in progression. For I find much iteration, but small addi- 
 tion." At that moment the world was standing at the 
 threshold of a great medical advance. The circle of medie- 
 valism had already been broken by the anatomist VesaHus 
 and his contemporaries ; the physiologist Harvey was soon 
 to announce the discovery of the circulation of the blood ; and 
 the labors of men of medicine were thereafter to result in 
 progression. During the seventeenth and eighteenth cen- 
 turies progression was destined to be slow; during the nine- 
 teenth it took on a sudden and unexampled acceleration. 
 Three hundred years have now elapsed since Bacon wrote, 
 and the progress has never been so swift as it is to-day. Each 
 twelvemonth ends with a record of great achievements, and 
 each new year begins with a clearer vision forward. Not- 
 withstanding this we frequently meet with a distrust of the 
 efficiency of medicine, a feeling that the physician knows far 
 B 1 
 
2 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 too little concerning disease -and its cure, and a tendency to 
 turn toward strange cults, making fair promises. Such dis- 
 trust is as old as medicine itself. Its cause is complex, and 
 I shall not now try to analyze it.' I do not believe that it is 
 justified. Doubting is indeed an entirely legitimate form of 
 mental exercise. The man of science who is not a doubter 
 has no claim to honorable standing. He who doubts not is 
 dead to science. But not all doubts are equally estimable. 
 There are those that betray much knowledge and those that 
 betray little. Goethe and Browning did not contradict one 
 another, although the one wrote, "Doubt grows with knowl- 
 edge," and the other, "Who knows most, doubts not." 
 
 Whatever distrust of medical potency may now exist, 
 arises largely from ignorance of the human body and the 
 present status of medical science. Among many persons this 
 ignorance is extraordinarily great. It is strange to find 
 thinking, reasoning, feeling men and women, who were born 
 with their bodies, who have lived long lives and grown old 
 with their bodies, who have clung to them in sickness and 
 in health, for better, for worse, who have used them for every 
 variety of human service, and yet deliberately hold themselves 
 aloof from a knowledge of bodily affairs. I suspect that we 
 have here an inheritance, through many generations, of the 
 medieval notion of the vileness of the body, a notion which 
 is out of keeping with the enlightened science of to-day. This 
 science shows within ourselves wondrous mechanisms and 
 adaptations, which ought to arouse a man's admiration if he 
 possesses a truly esthetic sense. The medical profession is 
 occasionally criticized for its alleged failure to take the laity 
 into its confidence and to serve as teachers as well as practi- 
 tioners of its principles. I shall not here discuss the question 
 ' For a fuller discussion of this distrust, see p. 165. 
 
A SKETCH OF THE NORMAL HUMAN BODY 3 
 
 in how far a physician is morally bound to be a pedagogue. 
 But in accepting the Jesup Lectureship, I was influenced 
 largely by the thought that through it I might perhaps be of 
 service to both the medical profession and an intelligent 
 public by telling the public something of what medical 
 leaders are doing. 
 
 A recent writer has drawn a graphic picture of the three 
 stages that appear in the history of medicine — those of 
 dogma, of empiricism, and of modern science. Dogma was 
 rife until the close of the Middle Ages ; empiricism charac- 
 terized the Renaissance and the centuries immediately follow- 
 ing ; while modern science is a matter of decades. However 
 sharply differentiated are these stages, something of science 
 characterized the earlier ones, while something of both dogma 
 and empiricism, though forever dethroned, still persists. It 
 would be fatuous to disparage the inheritance with which 
 medicine entered upon its present stage, but one would be 
 blind not to recognize its truly wonderful growth under the 
 influence of the scientific spirit of our generation. The stimu- 
 lus to this growth came partly from many extraneous and 
 now familiar sources. The discovery of oxygen, the estab- 
 lishment of the theory of the conservation of energy, the over- 
 throw of the mystical doctrine of vital force, the discovery of 
 protoplasm, the promulgation of the cell theory of organic 
 structure, and the formulation of the theory of evolution — 
 all contributed their share. The chief agents through which 
 the great change has come are the laboratory, now little more 
 than threescore and ten years old, and the method of orderly 
 experimentation which the laboratory alone could foster. 
 
 One of the first and most essential steps in the modem 
 expansion was the acquisition of a better understanding of 
 the human body in its normal condition of health. Here much 
 
4 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 has been accomplished. Though human anatomy is still 
 far from being a completed science, the gross structure of the 
 body was appreciated early. When we submit the body to a 
 physical examination, externally and internally, we find it to 
 consist, first, of a number of easily recognized parts, which 
 have long been known as organs. The existence of most of 
 the organs of the human body were recognized before the 
 Christian era. This knowledge was at first gained doubtless 
 chiefly from observation of the bodies of men killed in battle. 
 It was not until the famous school of Alexandria had reached 
 the zenith of its glory in the third century before Christ 
 that the human body became actually dissected for purposes 
 of study. Later, dissection fell into ill repute, and it has 
 required modern science to free it finally from obloquy and 
 prejudice. If we proceed farther in our physical examination 
 and look carefully at any one of the various organs, we find 
 it to be composed of a small number of materials, varying 
 in appearance and easily recognizable by the naked eye. 
 To these materials the name tissues has been given, and 
 we may distinguish such as muscular tissue, nervous tissue, 
 connective tissue, epithelial tissue, bony tissue, fatty and 
 cartilaginous tissue. Though the existence of tissues is 
 plainly obvious to an observer, it was not until one hundred 
 years ago that their structural significance was clearly recog- 
 nized — first, by a French anatomist, Bichat, who classified 
 them and pointed out their distribution within the body. It 
 is easy now, in the days of powerful microscopes and in- 
 tricate microscopical methods, to carry the physical exami- 
 nation of organs and tissues into the realm of what was un- 
 dreamed of by the ancients, and the significance of which 
 has been appreciated only within the lifetime of still living 
 men. But Bichat did not realize that all tissues are com- 
 
A SKETCH OF THE NORMAL HUMAN BODY 5 
 
 posed of recognizable particles, now called cells, of living 
 substance, now called protoplasm. Moreover, cytologists 
 do not stop here, but differentiate, within the cell, nucleus 
 and cytoplasm, centrosome and chromosomes; the ultra- 
 microscope is leading us on toward a sight of still smaller 
 components ; theories of the physical structure of protoplasm 
 are hotly discussed; and interchangeable states of solution 
 and gelation are thought to occur within it. 
 
 Living substance, in itself soft and delicate and gelatinous, 
 is permeated throughout by non-living water and by non- 
 living soUds, which are antecedents or products of cell 
 activities. Having said this, I ought to confess that often 
 it is a practical impossibility to decide what within a cell is 
 living and what is not living. Moreover, when we attempt 
 to submit the living substance and its contents to chemical 
 analysis, our first step results in its death and chemical change, 
 and we have no longer living, but only dead, substance in 
 our test-tubes. We are thus at first baffled in our endeavor 
 to determine the actual chemical structure of protoplasm, 
 and indeed we are here still in the realm of hypothesis. But 
 we are, nevertheless, making progress in learning the bricks 
 or chemical cleavage products, which result from the demoli- 
 tion of protoplasm and of which it is built up. All the various 
 chemical substances are composed of comparatively few of 
 the chemical elements. Only carbon, hydrogen, oxygen, 
 nitrogen, sulphur, phosphorus, chlorine, sodium, potassium, 
 calcium, magnesium, iodine, silicon, fluorine, manganese, and 
 iron are known to occur in every hvunan body. But these 
 are capable of entering into a long series of permutations and 
 combinations with one another, the various organic com- 
 pounds rarely possessing the simplicity of composition that 
 occurs in inorganic 'nature. Thus we find many representa- 
 
6 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 tives of the ever interesting group of proteins, huge molecules 
 containing hundreds, or even thousands, of atoms, which 
 seem to be arranged in most intricate patterns. For no 
 protein has this pattern yet been fully made out, but it is 
 believed that many of the atoms are grouped into the so- 
 called amino-acids, and that the protein molecules represent 
 still more intricate groupings of these groups, in themselves 
 complex. Besides a considerable number of proteins there 
 occur in protoplasm starches and sugars and fats of various 
 kinds and compositions, water, and various salts. The salts 
 probably exist, in part at least, as ions, electrically charged 
 atoms or groups of atoms, which are chemically combined 
 with the proteins, thus adding to the latter's complexity. 
 
 The scientific physician must understand not only the 
 morphological and chemical structure of the bodily machine, 
 but the way in which it acts. However complex structure 
 appears to be, it is simple when compared with function. 
 The modern physiologist looks upon the body as a machine, 
 a machine in which physical and chemical processes are con- 
 stantly occurring in orderly sequence and in which energy, no 
 more created here than elsewhere, is being constantly changed 
 from one form to another. Function is thus the expression 
 of physical and chemical principles, and it is the physiolo- 
 gist's endeavor to resolve the vital phenomena of organs, 
 tissues, and cells into their physical and chemical compo- 
 nents. He has already gone a long way in doing this ; but, 
 as might be expected of the science of the life process, every 
 problem solved leaves other problems awaiting solution, and 
 with every mystery mastered still other mysteries lure and 
 baffle. 
 
 Let me enumerate some of the chief functions of the body. 
 The heart by the force of its beats, which are contractions of 
 
A SKETCH OF THE NORMAL HUMAN BODY 7 
 
 its muscular walls, moves the blood, receiving it from the veins 
 and propelling it along the arteries. The actions of the 
 heart's valves, the sequence of activity and the dynamic rela- 
 tions of its parts, and its regulation by the nervous system are 
 fairly well understood. We can point with reasonable cer- 
 tainty to the spot at which the beat originates, but we are 
 not agreed as to the nature of the stimulus which sets it off 
 four thousand times during each hour of our Uves, or whether 
 the stimulus acts primarily on nervous or muscular tissue. 
 
 The lungs serve to introduce oxygen into, and to remove 
 carbonic acid from, the blood. For this purpose the lungs and 
 chest act together like a bellows, the moving power residing 
 in the muscles of the walls and floor of the chest, which are 
 under the control of the nervous system. We understand 
 much of the pneumatic conditions and the nervous relations 
 of the process, but we are still trying to learn in what manner 
 the exchange of oxygen and carbonic acid between the air 
 and the blood occurs. 
 
 The successive steps in the digestion of food occurring in 
 the stomach and intestine are recognized in the main. 
 
 From earliest times the liver has been misunderstood, often 
 maligned, and always the subject of hypothesis. The phys- 
 iology of to-day recognizes in it a considerable number of 
 important functions. Like certain parts of a plant's body, 
 its cells serve as a storehouse for such of the body's starch as 
 is not needed for immediate use, and on the demand of the 
 tissues they give this out to the blood in the form of easily 
 transported sugar. The liver is, in fact, the body's "sugar 
 trust" — without, however, employing the peculiar methods 
 that have made famous its modern namesake. It manu- 
 factures and give to the intestine bile, which is an important 
 aid to the digestion and absorption of fats, and an important 
 
8 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 medium for the removal of certain waste products of the 
 tissues' activities. It manufactures and gives to the kidneys 
 urea, another waste product, whose prompt removal from 
 the body is essential to health. To some extent the liver is 
 capable of protecting the body by rendering inert a variety of 
 poisonous substances, such as those that may have been pro- 
 duced within the intestine in the course of digestion, those 
 that may have been caused by disease germs, and even stich 
 poisons as strychnine, morphine, and metallic salts, which 
 may have been taken by the individual with good or evil 
 intent. Various as are the known activities of the liver, it 
 is probable that future research will reveal still others of 
 great importance. 
 
 The pancreas manufactures and sends to the intestine a 
 liquid which contains three ferments capable of digesting 
 proteins, fats, and starches, respectively. The kidneys and 
 their connected organs remove from the body a variety of 
 chemical substances, both organic and inorganic, which are 
 the end products of the body's chemical changes, and the 
 retention of which would be harmful. 
 
 Glands are an endless source of interest. We know that 
 from them appear characteristic liquids ; but why, from the 
 uniform store of materials in the blood supplied to all glands 
 in common, the salivary glands secrete saliva, the glands of 
 the stomach gastric juice, the liver bile, and the kidneys 
 urine, and as to what physical principles are involved in the 
 passage of the widely different components of these various 
 juices through the gland cells, we are much in doubt. Within 
 only a few years we have learned that besides producing and 
 excreting through their ducts their characteristic juices, 
 glands give back to the blood equally characteristic sub- 
 stances, many of which are indispensable to the continued 
 
A SKETCH OF THE NORMAL HUMAN BODY 9 
 
 activity of other organs and to life itself. This process has 
 come to be known as internal secretion, and the same term 
 is applied to the substances thus produced. Thus the liver 
 gives to the blood sugar and urea. The pancreas gives to 
 the blood, apparently only through the activity of certain 
 peculiar groups of its cells, a substance which, in some way 
 still to be determined, plays an important r61e in the 
 chemical changes undergone by sugar within the body. Re- 
 moval or serious disease of the pancreas results in the accu- 
 mulation of sugar in the blood and its constant loss from the 
 body in the urine, which are the striking symptoms of dia- 
 betes. An internal secretion of unknown nature seems to 
 come from the kidney. The peculiar bodies called the thy- 
 roids appear to produce a substance which is of great im- 
 portance to certain nutritive activities of the brain. The 
 absence of this substance may lead in the young to the pe- 
 culiar form of idiocy called cretinism, and in the adult to a 
 disease known as myxedema, both of which are characterized 
 by symptoms of mental deterioration. An excess of thyroid 
 secretion, on the other hand, may lead to an equally distress- 
 ing disease, known as exophthalmic goiter. Still other 
 organs yield equally striking internal secretions. In fact, 
 internal secretions seem to constitute one of the chief media 
 by which parts of the body act upon other parts, often in the 
 most profound and unexpected ways. The principle of such 
 cooperation in bodily activity has been discovered only re- 
 cently, and we are quite prepared to learn at any time of 
 new instances of it. 
 
 One of the most active fields of research in physiology 
 to-day is that which deals with the chemical changes under- 
 gone by the body in the process of living. Half a century 
 ago this was largely a matter of speculation. Now we 
 
10 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 recognize that, with its living and its non-living substances 
 inextricably intermingled, the body constitutes an intensive 
 chemical laboratory in which there is ever occurring a vast 
 congeries of chemical reactions ; both constructive and de- 
 structive processes go on ; new protoplasm takes the place 
 of old. We can analyze the income of the body and we can 
 analyze its output, and from these data we can learn much 
 concerning the body's chemistry. A great improvement in 
 the method of such work has recently been secured by the 
 device of inclosing the person who is the subject of the ex- 
 periment in a respiration calorimeter. This is an air-tight 
 chamber, artificially supplied with a constant stream of pure 
 air, and from which the expired air, laden with the products 
 of respiration, is withdrawn for purposes of analysis. The 
 subject may remain in the chamber for days, the composition 
 of all food and all excreta being determined, and all heat 
 that is given off being measured. Favorable conditions are 
 thus established for an exact study of many problems of 
 nutrition. The difficulties increase when we attempt to 
 trace the successive steps in the corporeal pathway of mole- 
 cule and atom. Yet these secrets of the vital process are 
 also gradually being revealed. When we remember that it is 
 in this very field of nutrition that there exist great popular 
 ignorance and a special proneness to fad and prejudice, we 
 realize how practically helpful are such exact studies of 
 metabolism. 
 
 I have likened the body to a machine. A more fitting 
 simile would be that of an intricate industrial plant, in which 
 varied machines work to produce a certain output. The first 
 essential in such an establishment is order. The work of 
 each machine must be methodical ; its raw material must be 
 supplied in just the right quantity and at just the right time ; 
 
A SKETCH OF THE NORMAL HUMAN BODY 11 
 
 its products, both useful products and wastes, must be 
 removed promptly and taken to their destinations; and 
 a harmonious adjustment of the labors of the respective 
 parts of the plant must be continually maintained, if 
 confusion and chaos are not to reign. The human body 
 possesses two mechanisms for the maintenance of order 
 and harmony among its varied parts, — the blood cir- 
 culating through heart, arteries, capillaries, and veins, and 
 conveying material substances, and the nervous system 
 conveying immaterial nervous impulses. Nothing illustrates 
 so well the relations of bodily functions as a consideration 
 of these two systems. 
 
 The blood consists of a liquid part, the plasma, and a large 
 number of minute, floating cells, or cell-like particles, called 
 corpuscles. The plasma is capable of holding in solution a 
 great variety of solid substances. It is the medium by which 
 food and drink and drugs are conveyed to all portions of the 
 organism, carbonic acid to the lungs, and other wastes to the 
 excretory glands. Products of protoplasmic action which are 
 the result of internal secretion and are to be used elsewhere 
 than in their place of origin, are shipped by way of the 
 plasma to their destinations. Those toxic products of ex- 
 cessive activity that are known as fatigue substances are 
 transported by the plasma to all tissues, and thus make it 
 possible that the fatigue of a working organ may be extended 
 even to those that have been resting. Whatever a tissue 
 requires it receives from the store available in the blood 
 plasma, and whatever it is to give up passes to the same 
 medium. 
 
 The blood corpuscles are of three kinds — blood plates, red 
 corpuscles or erythrocytes, and white corpuscles or leucocytes. 
 The blood plates are a comparatively recent discovery, and 
 
12 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 their functions are not yet well understood. The very abun- 
 dant erythrocytes have long been known for their power of 
 absorbing large quantities of oxygen, and in the course of 
 evolution they seem to have become differentiated for the 
 express duty of conveying to the tissues this essential gas. 
 That this power is adapted to the bodily needs is shown by the 
 fact that life in high altitudes, where the actual oxygen con- 
 tent of the air is relatively low, leads to a marked increase 
 in the number of erythrocytes, and thus to an increased power 
 on the part of the blood of absorbing oxygen. Until recent 
 years the leucocytes have been regarded as humble and insig- 
 nificant members of the organic colony, but they have now 
 risen to a dignity that is surpassed by few other cells. Like 
 the amoeba they possess the power of independent motion, 
 and like nomads they wander at will. I say "at will" fanci- 
 fully. We have no reason to believe that leucocytes possess 
 consciousness. When it pleases them they allow themselves 
 to be carried along in the blood stream, but ever and anon 
 they forsake the blood-vessels, push their way through the 
 walls, and roam up and down among the tissues. It is pos- 
 sible that they act as carriers of food, such as fats and pro- 
 teins, when these substances are ready to enter the tissues 
 after the digestive ferments have dealt with them. They 
 assist in the peculiar and often life-saving process of coagu- 
 lating blood. They seem to be factors in maintaining the 
 desired chemical composition of the blood plasma. They 
 probably manufacture substances that are destructive to 
 bacteria. And, lastly, they engulf worn-out body substance, 
 living bacteria, and other matter foreign to the body, should 
 such be present, and thus protect the body from harmful 
 agencies.' 
 
 • See also pp. 45, 77 and 79. 
 
A SKETCH OF THE NORMAL HUMAN BODY 13 
 
 Pumped by the heart, the blood circulates in arteries, 
 capillaries, and veins throughout the body to its remotest 
 parts and back again to the heart. In the thin-walled cap- 
 illaries its liquid plasma exudes into the interstitial spaces 
 of the tissues, accompanied by numbers of leucocytes, and 
 the two together constitute the lymph. It is only through 
 the lymph that the exchange between blood and tissue is 
 effected. 
 
 Even with the elaborate blood system with its many func- 
 tions the diversified body without other agency would still 
 be unable to live a unified life. To harmonize, correlate, and 
 unify is the special function of the nervous system. Without 
 a nervous system oiu- members might exhibit a certain de- 
 gree of spontaneity, but it would be the spontaneity of un- 
 bridled license, and anarchy would soon put an end to us. 
 For more than two thousand years men have been endeavor- 
 ing to fathom the mysteries of brain and nerve, and their 
 ultimate problems seem now as enigmatical as ever. Even a 
 rational idea of the structural basis of nervous action has 
 been acquired only within three decades, and there are some 
 biologists who are still skeptical of this. According to the 
 prevalent conception, the nerve-cell, now called neurone, is the 
 imit of nervous structure. Like other cells, it possesses a 
 central, nucleated body of microscopic size, but unlike other 
 cells, there extend far outward from its body in various direc- 
 tions dehcate filaments. The numerous, comparatively 
 short, and much-branched filaments are called dendrites; 
 the few, comparatively long and little-branched, axones. A 
 human nervous system, with its brain, spinal cord, ganglia, 
 and nerves, is a mass of neurones. The bodies of the neurones 
 and their dendrites lie mostly within the brain, spinal cord, 
 and ganglia, in more or less definitely localized masses. 
 
14 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 The axones are mostly collected together into definite bundles 
 or tracts, of which some lie within the brain and spinal cord, 
 but many extend outward and, as the constituent nerve-fibers 
 of nerves, reach all parts of the body. Through the nerves 
 all organs and tissues are in communication with, the brain 
 or spinal cord, and only through the brain or spinal cord do 
 organs and tissues possess the possibility of communicating 
 with one another. Neurones, while often in contiguity and 
 seemingly inextricably mingled, do not appear to be actually 
 continuous with one another. Their number is legion, and 
 through them the infinitely complex work of the nervous sys- 
 tem is performed in an orderly, methodical manner. The 
 messages which they transmit are called by the physiologist 
 nervous impulses. Many theories of the nature of nervous 
 impulses have been proposed, and though no theory is wholly 
 satisfactory, we believe that in them certain physical, prob- 
 ably electrical, and chemical processes are involved. Each 
 nerve-fiber seems to conduct impulses in one direction only. 
 Outside the brain or spinal cord certain of the fibers conduct 
 only from the tissues and toward the central nervous system, 
 while certain others only in the opposite direction. Every 
 organ seems to possess both of these afferent, or centripetal, 
 and efferent, or centrifugal, fibers, and thus is able both to 
 send and to receive impulses. Incoming impulses inform the 
 brain or cord of the physiological state of the particular organ 
 from which they come; they may give rise to sensations, 
 and are then called sensory. The most striking functions of 
 pm-ely sensory nerves are those of the so-called special senses. 
 Outgoing impulses are never in themselves sensory, although 
 the brain actions that inaugurate many of them may be 
 accompanied by conscious acts of the will. They inform the 
 organs or tissues what to do under the circumstances. The 
 
A SKETCH OF THE NORMAL HUMAN BODY 15 
 
 following is a classification of the known varieties of nerve- 
 fibers, according to their functions. 
 
 Afferent 
 
 Efferent 
 
 Excitatory 
 
 Inhibitory : 
 
 Excitatory 
 
 Inhibitory : 
 
 Sensory: controlling sensations of 
 sight, hearing, smell, taste, 
 pressure, temperature, pain, 
 etc. 
 
 Reflex: inducing reflex actions 
 through efferent fibers. 
 
 inhibiting reflex actions. 
 
 Motor: supplying voluntary mus- 
 cles, the heart, and the muscles of 
 arteries, stomach, intestines, etc. 
 
 Secretory : supplying salivary 
 glands, glands of the stomach, and 
 the pancreas, sweat-glands, etc. 
 
 inhibiting the activities of the 
 muscles and glands. 
 
 Within the brain and spinal cord the various nerve-fibers, 
 grouped into different bundles, offer definite routes for the 
 conduction of nervous impulses. In some the impulses 
 pass upward, in others downward, in still others from side 
 to side. Through them the organs and tissues communicate 
 with the various parts of the brain and spinal cord, and these 
 in turn communicate with one another. 
 
 A single act, however simple it may appear to be, usually 
 involves many nervous phenomena. Thus the voluntary 
 contraction of one's biceps muscle means the ti'ansmission, 
 not only of excitatory impulses to the biceps itself, but of 
 inhibitory impulses to its antagonist, the triceps; other 
 excitatory and inhibitory impulses to adjacent muscles for 
 the purpose of inducing in them just the right degree of ten- 
 
16 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 sion in order that the biceps may be aided ; dilating impulses 
 to the arteries of the various contracting muscles and con- 
 stricting impulses to arteries elsewhere, in order to supply 
 the muscles with more blood ; impulses to the heart to beat 
 more strongly, in order that the demands of the arteries for 
 blood may be met ; increased naotor impulses to the muscles 
 of respiration; increased secretory impulses to the sweat- 
 glands and dilating impulses to their arteries; and perhaps 
 other nervous impulses to other organs. If, moreover, we 
 realize that with each one of these separate actions special 
 afferent nervous impulses go to the nervous system announc- 
 ing the nature and extent of the action, we may in our be- 
 wilderment well wonder why a mere innocent contraction of 
 the biceps does not bring in its train an attack of nervous 
 prostration. Gay critics of the medical profession, anti- 
 this, and anti-that, who wonder why the problems of health 
 and disease have not been solved long ago, have little con- 
 ception of the intricacies of the human body. 
 
 One of the greatest achievements of the modern physiology 
 of the nervous system has been the exploration of the various 
 parts of the brain and spinal cord and the discovery that each 
 part has its own specific work to do. The parts that are 
 composed chiefly of the bodies of nerve-cells are known as 
 nerve-centers, and it is customary to picture the brain and 
 cord as consisting largely of innumerable centers connected 
 with one another by tracts of nerve-fibers. Along the whole 
 length of the cord there is a series of such functional centers, 
 which deal with the activities of the muscles of the trunk and 
 limbs and some of the abdominal organs. The bulb, or medulla 
 oblongata, is a mass of most important centers dealing with 
 such essential features as breathing and the actions of the 
 heart, the arteries, and the glands. In the much-folded 
 
A SKETCH OP THE NORMAL HUMAN BODY 17 
 
 outer layer, or cortex, of the cerebrum lie the innumerable 
 centers whose activities are accompanied by consciousness, 
 and here we locate the volitional factors of locomotion, the 
 movements of arms, hands and fingers, speech, sight, hearing, 
 taste, smell, and touch. Here also are mediated the psychic 
 processes of perception, conscious memory, the association of 
 ideas, and the thousand and one features of mental life. A 
 scientific cerebral phrenology has thus replaced the doctrine 
 of cranial bumps and excrescences, which was advocated so 
 strenuously by Gall and Spurzheim seventy-five years ago, 
 and which impressed so many of our fathers. Yet there is 
 still much unknown territory lying within the skull, and 
 cerebral geography offers to the intrepid explorer prizes of 
 infinitely greater importance to the human race than those 
 won, however gallantly, by Nansen, Scott, and Peary. 
 
 In this rapid and very incomplete sketch of the structure 
 and functions of the normal human body, I have endeavored 
 to give to you something of the spirit of modern physiology 
 and to impress you with the variety and complexity of our 
 bodily machine. Unless one learns it step by step one may be 
 overwhelmed with the intricacy of it all. We should bear in 
 mind that the intricacies of both structure and function are 
 the result of a long evolution. Of the mode of origin of the 
 earliest rudiments of organs we can only speculate, but it 
 may conceivably have been a more rapid process than their 
 subsequent change into complicated mechanisms. Loco- 
 motion, even in the unicellular forms, required contractile 
 protoplasm. When the primitive organism became so large 
 that it could not obtain sufficient food by direct absorption 
 from its environment, it may have been a simple matter to 
 infold and produce a primitive alimentary canal. A simple 
 system of tubes permeating the body and containing a nutrient 
 
18 SCIENTIFIC FEATURES OF MODERN MEDICINB 
 
 liquid soon followed. A simple method of nervous commu- 
 nication between the parts originated early, and along with 
 it certain simple sense-organs. Thus in the more simple of 
 the ccelenterates we find muscular, alimentary, circulatory, 
 and nervous systems already begun, and ready for the subse- 
 quent long process of development. Within the walls of the 
 circulatory system a localized aggregation of muscle cells 
 formed a simple heart. An extension of the surface tissues 
 became a respiratory gill. Glands secreting digestive ferments 
 appeared in connection with the ahmentary canal. Other 
 glands communicating with the surface of the body carried 
 off waste products. An aggregation of neurones performed 
 the simple function of a primitive brain. Nerves were multi- 
 plied, and nervous functions became more diverse. New 
 sense-organs appeared, by which the organism could acquaint 
 itself with the various forms of energy in the external world. 
 A change from the original aquatic to a terrestrial life involved 
 the appearance of lungs and other profound transformations. 
 Simultaneously with the ever increasing complexity of struc- 
 ture came physiological differentiation and physiological 
 integration — the greater the differences within the body, the 
 greater became the correlation between the parts. And so, 
 step by step, through ages of trial, now advancing, now 
 receding, the intricacies of form and function that we find 
 most completely developed in man's body slowly appeared. 
 
 In surveying the working of a human body there is one 
 topic which has been of absorbing interest to physiologists, 
 physicians, and philosophers of all ages, and at the present 
 time, with its many systems of mental healing, is much 
 attracting the attention of the lay public. This is the prob- 
 lem of mind, its nature, the relation of mind and body, and 
 the possibility of their mutual influence. To consider this 
 
A SKETCH OF THE NORMAL HUMAN BODY 19 
 
 topic is to enter a field of many and diverse opinions, where 
 speculation has always been rife, where experimentation is 
 difficult, and where superlative uncertainty is still supreme. 
 To the naive thinker, mind and body are two distinct entities, 
 dififerent in nattire — the one spiritual, the other material — 
 and each capable of existing and acting apart from the other, 
 and of inducing, modifying, and arresting activity in the other. 
 To the physiologist this view presents insurmountable diffi- 
 culties. Neither introspection nor extrinsic observation nor 
 laboratory experimentation reveals to him a mind outside a 
 nervous system. He associates human consciousness only 
 with the cortex of a himian cerebrum, and only when the 
 cortical neurones are active, — in sleep and other forms of 
 unconsciousness mind no longer exists, except when dreams 
 interpose their feeble and fantastic images. Every mental 
 phenomenon has its neural counterpart, although the vast 
 majority of neural processes are devoid of a mental accom- 
 paniment. It is a favorite attitude of physiologists thus to 
 look upon mind as a sign of brain activity, as only one of the 
 several phenomena by which cerebral neurones manifest 
 their activity, albeit mind seems more mysterious than the 
 phenomena which we call physical, such as changes in tem- 
 perature, in electrical state, and in chemical composition, all 
 of which are manifest when brain cells act. This hypothesis 
 does not postulate the nature of mind, but it regards mind 
 as an accessory phenomenon, or epiphenomenon, and not 
 as the supreme inhabitant of the cerebral protoplasm. If 
 this hypothesis be true, we must alter our naive ideas concern- 
 ing the interaction of body and mind. Thus bodily changes 
 may madify mental action, but only by modifying brain 
 action. So, too, the brain through the nerves may modify 
 bodily action. But the mind itself, a sign of brain activity, 
 
20 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 cannot influence matter, and thus can never be the directing 
 agency of either brain or body. All supposed influence of 
 the mind over the body is thus reduced to brain influence, 
 which, however, may be mirrored in mental acts. Such an 
 hypothesis, whatever its future, appears to me to be the most 
 fruitful working hypothesis for the physiologist at the present 
 time, and it would appear to clarify the now puzzling field 
 of psychotherapy. 
 
 We ought not to leave the consideration of the activities 
 of the human body without a glance, however brief, at the 
 problem of the nature of vital actions in general and their 
 control. From the beginning of human speculation — and 
 that means from the beginning of the human race — down 
 to the era of modem science, when speculation has been forced 
 to give way to demonstration, it was thought that a peculiar 
 power resided in the body which was immediately responsible 
 for bodily actions. This power was variously believed to be 
 material and immaterial. The doctrine which lived longest 
 was that of the pneuma, or spirits, which were conceived as 
 matter in an extremely tenuous state, permeating the body 
 and directing the grosser matter of which the body is com- 
 posed. The Greek physicians, five hundred years before 
 Christ, beUeved in the spirits, as did their successors in both 
 Greece and Rome. All through- the Middle Ages the spirits 
 held sway, but after the Renaissance had set men free from 
 slavish tradition, there entered doubts and a lack of agree- 
 ment as to what constitutes the directing power in vital ac- 
 tions. Various immaterial agencies were then invoked — 
 the anima or soul, the archeus, the ether, the nervous prin- 
 ciple. But these in turn gave way with the advent qi a final 
 form of the general doctrine. This was the hypothesis that 
 vital actions are manifestations of a specific force, differing 
 
A SKETCH OF THE NORMAL HUMAN BODY 21 
 
 from the forces of inorganic nature, but peculiar to living 
 things, and hence called vital force. The belief in a vital force 
 was almost universal from about the middle of the eighteenth 
 to the middle of the nineteenth century. But toward the 
 end of the period the great advance of physics and chemistry 
 and the application of the new discoveries to living processes 
 profoundly shook the existing belief in regard to the nature of 
 vital phenomena, and led, by the middle of the last century, 
 to the practical abandonment of the doctrine of vitalism. 
 Thus ended the endeavors to explain vital actions by means 
 of a single mysterious principle, and men turned their atten- 
 tion to the discovery of the physical and chemical phenomena, 
 which were, and are still, recognized as the essence of the mani- 
 festation of life. The question of vitalism or mechanism is 
 not yet beyond the sphere of debate, but the mechanistic 
 mode of interpreting the phenomena of nature has proved to 
 be the one under which the most rapid progress in discovery 
 has yet been made. One of the scientific features of modern 
 medicine, therefore, is no longer to regard the human body as 
 a thing of mystery, which will forever be inexplicable, but to 
 believe that every part of it, sooner or later, will give up its 
 secrets — to the same extent at least that non-living nature 
 will yield hers. 
 
II 
 
 THE NATUEE OF DISEASE. METHODS OF DIAGNOSING DISEASE 
 
 In the last lecture I endeavored to present a picture of the 
 human body in a state of health, healthy as to both structure 
 and function. To-night I intend to devote the hour to a 
 subject which is popularly less inviting, but to the man of 
 science not less interesting, namely, that of the body in the 
 throes of disease. By disease we customarily mean that 
 condition in which bodily function or bodily structure exhibits 
 a deviation from what has come to be regarded as the normal. 
 A distinction is sometimes made between structural and func- 
 tional diseases, the fortner being those that are characterized 
 by abnormalities of structure, the latter those in which struc- 
 tural abnormalities are wanting. However convenient such 
 a distinction may be, it is bound, I think, to be dispensed with 
 in the course of time and of increased knowledge, for it is 
 impossible to believe that a condition of altered function can 
 exist, which does not simultaneously involve an alteration of 
 anatomical or chemical structure. Our present knowledge, 
 however, is not sufficient to demonstrate such alteration in all 
 diseases. 
 
 The most universal phenomenon of disease, therefore, is 
 perturbed or altered function. No sharp line can be drawn 
 between the normal and the diseased. There are wide and 
 indefinite limits of variation in the working of bodily organs, 
 and it is usually only when the extreme limits are passed and 
 the changed condition continues that it is called pathological. 
 
 22 
 
THE NATURE OF DISEASE 23 
 
 Thus, the heart of an adult man in middle life beats usually 
 with a perfectly regular rhythm and at an average rate of 
 seventy-two times in the minute ; but there may at times be a 
 temporary irregularity or a considerable slowing or quicken- 
 ing without the presence of disease. The bodily temperature, 
 the average of which, when measured in the mouth cavity, is 
 about 98.4° F. in the healthy adult, has a normal daily varia- 
 tion of one and one half degrees or more, and only when it 
 rises to a considerable height or sinks to a considerable depth 
 and there remains, do we suspect anything abnormal. 
 
 Disease rarely involves a single function alone. When the 
 alteration of one function has passed beyond the limits of the 
 normal, it is almost certain to carry others in its train. Thus, 
 if the valve between the left am-icle and the left ventricle of 
 the heart leaks and becomes incapable of closing the orifice 
 between the two chambers, the onward movement of the blood 
 is interfered with ; the lungs may become gorged with blood; 
 and this engorgement may reach backward to the right side 
 of the heart and the veins of the body generally. At the same 
 time too little blood may pass on from the left ventricle to the 
 arteries. The results may be far-reaching. The heart muscle 
 may become increased in quantity in the endeavor to com- 
 pensate for the circulatory disturbance by a more powerful 
 beat. The heart may, however, suffer from palpitation, weak- 
 ness, and irregularity. The person may be distressed from 
 lack of the proper respiratory exchange of oxygen and carbonic 
 acid. Bronchitis, cough, and hemorrhage from the lungs may 
 occur. The cavities of the chest and the abdomen may be- 
 come partially filled with liquid that has exuded from the 
 blood. The legs may likewise become cedematous from the 
 same reason. There may be nausea and loss of appetite, and 
 digestion in the stomach may be interfered with. The liver 
 
24 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 may become congested ; blood may escape into its tissues and 
 its cells may midergo atrophy, while its various functions 
 may be seriously deranged. And lastly, the kidneys may, 
 perform their work only in part. 
 
 From this involvement of other organs besides the primarily 
 diseased one it follows that a disease may often be an affair 
 of very great complexity. We often speak of the symptoms 
 of a disease as if they were to be distinguished from the thing 
 that gives rise to them. The word " symptoms " is used, 
 rather loosely, to signify the more obvious signs of the dis- 
 ease. If, however, we should employ the word in a strict 
 sense, as including all the pathological phenomena, symptoms 
 and disease would be synonymous terms, the disease being 
 nothing more or less than the sum of its symptoms or mani- 
 festations. Just as normal function is now regarded as a 
 matter of chemistry and physics, so is disease; the symptoms 
 of disease being changed chemical or physical conditions. 
 Disease is not, therefore, a specific entity, a thing, arising 
 spontaneously within the body or entering it from without. 
 It is merely a change from what has come to be regarded as 
 the normal. 
 
 But this modern conception has not always been the 
 accepted one, and a most interesting chapter in human 
 history is that which deals with the views that have been 
 held respecting the nature and causation of disease. As 
 might be expected, these views have been many and va- 
 rious. According to the earliest known and a very persistent 
 conception, disease is a demon or strange spirit, which has 
 invaded the body and causes it to perform new and unwonted 
 actions. This view was held by the Sumerian predecessors 
 of the Babylonians, by the Babylonians themselves, and by 
 later peoples, and it is still found among primitive races. 
 
THE NATURE OF DISEASE 25 
 
 With some peoples the demon is the spirit of a human being, 
 who has lived and died, and whose ghost returns to inhabit 
 again for a period a living body. This theory of demoniac 
 possession was widespread among the Jewish races at the 
 time of Christ, and the casting out of devils was a common 
 method of healing. Christ himself not only drove such evil 
 or unclean spirits out of the body, but he said of those who 
 believed in him, "In my name shall they cast out devils." 
 Even down to quite recent times civilized people have be- 
 lieved in demoniac possession, especially by those suffering 
 from mental or nervous diseases. Allied to this is the belief 
 in witches, and although it has been more than two hundred 
 years since the last witch was hanged at Salem, this strange 
 delusion has probably not yet died out among the ignorant 
 of our land. 
 
 From time immemorial, by both the adherents and the 
 opponents of the demoniac theory of disease, endeavors have 
 been made to find an explanation in natural or material 
 agencies. The first to do this in a really effective manner was 
 an eminent Greek physician, Hippocrates by. name, who lived 
 in the fifth century before Christ. The title of "Father of 
 Medicine" has been given to Hippocrates by those system- 
 loving historians who find satisfaction in ascribing to single 
 individuals the paternity of great sciences. This title is 
 deserved not so much by reason of the original contributions 
 which Hippocrates made, as because he and his contemporaries 
 present, in the large body of Hippocratic writings, a graphic 
 and stimulating picture of the best medicine of their time. 
 The Hippocratic writers upheld nobly the ideals of the medi- 
 cal vocation. They assumed to exist within the body four 
 cardinal fluids, or "humors," which they called respectively 
 blood, phlegm, yellow bile, and black bile. Health is present 
 
26 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 when the humors exist in proper quantities and proper rela- 
 tions to one another ; disease when the proper quantities and 
 relations are disturbed. This was the beginning of the so- 
 called humoral pathology and of an academic controversy, 
 which has raged for twenty-three hundred years and the 
 echoes of which have not wholly died away, between those 
 who ascribe disease to the fluids and those who ascribe it to 
 the solids of the body, the humoralists and the solidists. 
 The humoral hypothesis has stamped itself indelibly in popu- 
 lar speech. While not subscribing to the Hippocratic pathol- 
 ogy we may be good-humored or bad-humored ; the melan- 
 choly person is suffering from black bile, the choleric person 
 from yellow bile; and he who possesses a phlegmatic or a 
 sanguine temperament derives it from the excess of his 
 cardinal phlegm or blood. 
 
 Hippocrates and his followers, among whom ought to be 
 especially mentioned the great Roman physician Galen of 
 the second century before CErist, did not, however, ascribe 
 all disease solely to the faults of the humors ; for the pecca- 
 dilloes of the pneuma had still to be reckoned with, the ex- 
 tremely subtile material spirits, which were believed to be 
 largely responsible for bodily actions. From the time of 
 Pericles and Sophocles and Praxiteles down to that of 
 Charles I, Harvey, and Descartes, a heavy burden of disease 
 was laid upon the humors and the spirits. But even these 
 two thousand years of supremacy could not prevent the in- 
 vestigators of the Renaissance from having discourteous doubts 
 about the importance and even the existence of these two 
 agents. One of the first of the doubters was Paracelsus, who 
 had alchemistic tendencies and who was bold and illogical 
 enough to displace the humors with still more hypothetical 
 substances, symbolically termed "sulphur, mercury and salt," 
 
THE NATURE OF DISEASE 27 
 
 and the pneuma with the equally mysterious "archeus." 
 The stomach was the seat of the archeus, and if it did not 
 perform its duties properly, disease resulted. It was also a 
 favorite notion of the time that diseases were sent by God 
 as a punishment for the sins of man. " Ira Dei " as a cause of 
 disease has perhaps not yet wholly disappeared from some 
 circles, even though it is not met with in the clinic and the 
 reports of the board of health. Further causes were sought 
 in supposed "fermentations," "stoppages" within the blood- 
 vessels or nerves, and various mysterious dynamic agencies. 
 All these strange ideas culminated in the "vital force" of a 
 century ago. But with the great extension of the scientific 
 mode of thought and the increase of scientific knowledge that 
 occurred during the first half of the nineteenth century, which 
 were marked among other things by the rise of the science of 
 biology, pathological doctrine underwent a profound change. 
 Men of medicine saw the futility of attempting to explain all 
 diseases by means of a common principle; "systems" were 
 done away with ; uncontrolled speculation and deductive 
 reasoning from hypothetical assumptions were replaced by 
 laboratory and clinical observations ; and modern scientific 
 medicine, with its conception of disease as altered function, 
 accompanied by more or less obvious alteration of structure, 
 was born. 
 
 Pathological alterations of structure and function may be 
 innumerable. To illustrate their possibilities let me enu- 
 merate some of the various disorders that may befall two 
 of the body's organs, the heart and the liver; the one in 
 which physical, the other in which chemical, phenomena 
 predominate. 
 
 The heart's muscular walls may become unduly increased 
 in thickness, owing to excessive growth of its muscular tissue. 
 
28 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 Its muscle cells may become separated from one another, or 
 torn into fragments, or their substance may be replaced in 
 part by fat or chalky material or other useless substances; 
 this may lead to weakening and even rupture of the heart 
 walls. The connective tissue within the walls may become 
 the seat of harmful changes; tumors may develop therein. 
 The arteries supplying the walls with blood may become closed 
 by particles cast off from other diseased organs, and this in 
 turn may lead to degeneration of the heart tissue. The peri- 
 cardimn, or membrane surrounding the heart, may become 
 the seat of dangerous inflammation or other affections. The 
 heart's cavities may become unduly dilated. The endocar- 
 diimi, or membrane lining the heart's walls, may undergo 
 inflammatory changes and become the seat of foreign growths 
 associated with the presence of bacteria. The same events 
 may occur in the valves, which may also become thickened, 
 hardened, or otherwise deformed. They may become in- 
 capable of adequately closing, and thus regurgitations of the 
 blood from one cavity to another, or from the arteries to the 
 heart, may occur; in this way the onward progress of the 
 blood may be seriously interfered with. The openings be- 
 tween the heart chambers, or between the chambers and 
 the arteries may become narrow, and thus again the prog- 
 ress of the blood may be hindered. The heart beats may 
 become unduly slowed or quickened, or augmented or weak- 
 ened in force ; they may occur irregularly, owing to a variety 
 of causes; the chambers may possess different rhythms. 
 The terrible pain of angina may occur. There may exist 
 various malformations of the heart which date from foetal 
 life, and seriously incapacitate the organ for meeting adult 
 conditions. And, lastly, this all-important organ is subject, 
 like other organs, to wounds and other external injuries. 
 
THE NATURE OP DISEASE 29 
 
 These are some of the more pronounced abnormalities in 
 one of the body's organs. Probably there are many others 
 which are still obscure. The careful observation and ex- 
 perimentation of the future will reveal them. 
 
 Let me here interpolate a warning against a possible danger. 
 It is a rather common tendency of the introspective human 
 mind, when contemplating the pictm-e of a disease, to transfer 
 its details to one's own person. You have perhaps, heard of 
 the author into whose hands there once fell a book on 
 diseases, and who was sufficiently bedevilled by it to read it 
 through. As he proceeded, to his growing horror he found 
 that one by one he possessed in his own body the successive 
 symptoms, and at the end of the book he came to realize that 
 he was the victim of each and every malady therein described 
 — except one, which went by the plain English name of 
 "housemaid's knee," whatever that may mean. I have a 
 medical friend whose name is well known among men of 
 science, and who rarely investigates a disease without com- 
 ing to believe that he himself suffers from it. Each disease 
 remains until it is duly displaced by the next in the course 
 of his researches. I trust that you will not leave this hall 
 to-night with the belief that your own hearts are affected by 
 the many disorders that I have just enumerated. 
 
 The heart's functions are primarily mechanical, and corre- 
 spondingly its diseases are manifested chiefly by mechanical 
 phenomena. With other organs, such, for example, as the 
 liver, chemical phenomena predominate both in health and 
 disease. The diseases of the liver are characterized anatomi- 
 cally by various forms of degeneration or death of the liver 
 cells ; increase in its co'nnective tissue ; the appearance of ab- 
 scesses, cancer, and other tumors ; various inflammatory, ca- 
 tarrhal, or other conditions of the bile ducts, which obstruct 
 
30 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 the outflow of bile and may lead to its passage into the 
 blood — a condition which is known as jaundice ; inflamma- 
 tion of the gall bladder; the appearance therein of gall 
 stones; various affections of the hepatic blood-vessels and 
 lymphatic vessels, and, lastly, injuries or malformations, a 
 common cause of which is tight lacing. As might be expected, 
 these structural abnormalities are associated with functional 
 disturbances. The capacity of the hver to store up starch 
 and to feed the body's tissues may be interfered with ; the 
 production of bile, with whatever that fluid means to diges- 
 tion and the absorption of food, may be diminished; the 
 elimination of harmful waste matters may be lessened, with 
 a resultant overloading of the organism with them; and 
 various poisonous substances may pass on to the tissues 
 without receiving their customary detoxication. Experi- 
 ment seems to show that some of these disorders may occur 
 without harmful results to the individual, but most of them 
 are, in all probability, seriously detrimental. 
 
 This brief enumeration of some of the diseases to which two 
 of the essential organs of the body are subject, will prove 
 sufiicient, I trust, to give you some notion of "the thousand 
 natural shocks that flesh is heir to." In thinking of them, 
 moreover, we should bear in mind what I have previously 
 said, that any one of them is rarely limited to the primary seat 
 of the disease, but is practically certain to involve other 
 organs and other functions. And herein lies much of the 
 seriousness of any pathological state, while this fact, more- 
 over, increases the difficulties of the physician. 
 
 Because of our ignorance of the nature and cause of many 
 maladies no classification of diseases that has yet been pro- 
 posed is altogether satisfactory. The following list includes 
 some of the main groups of human diseases : — 
 
THE NATURE OF DISEASE 31 
 
 (1) Infectious diseases; e.g. typhoid fever, smallpox, 
 tuberculosis, diphtheria. 
 
 (2) Poisoning; e.g. alcoholism, morphia habit, lead pois- 
 oning. 
 
 (3) Constitutional diseases; e.g. rheumatism, gout, dia- 
 betes. 
 
 (4) Diseases of organs. 
 
 When a physician is called upon to treat a case of illness, 
 the first task that confronts him is that of determining the 
 nature and the primary seat of the disease. His success in 
 treatment must presuppose a correct diagnosis. Here his 
 troubles begin. If his patient were a non-living machine, 
 whose mechanism could be readily taken apart and whose 
 parts could be separately examined, repaired, cleaned, lubri- 
 cated, tested, and replaced, the location and nature of the 
 disease might be readily discovered and a cure might be 
 readily effected. But he has no such easy task. His patient 
 is a living, sentient, human body, endowed with the most 
 mysterious of all qualities, whose members cannot at will be 
 removed and returned to their places, and whose secrets are 
 largely hidden from even the most careful observation. 
 Through only a few avenues are these secrets revealed. 
 From the beginning of the human race these avenues have 
 not changed, and it is one of the great achievements of 
 modern scientific medicine that along them have been found 
 innumerable clues of which physicians of even a century ago 
 had no conception. Scientific diagnosis, though it is still 
 far from the ideal and still finds itself too often mistaken, 
 has in recent years made great strides. This is due largely 
 to the fact that exact physical and chemical methods for 
 detecting disease have come into use. From the earliest 
 healing down to about the beginning of the nineteenth 
 
32 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 century, physicians had few means of diagnosis except those 
 of the unaided senses. Sounds and specula had occasionally 
 been employed for exploring some of the body's orifices. 
 There were men in advance of their time who had applied 
 the thermometer to the skin for determining bodily tempera- 
 tiu-e, and the watch had likewise been used for counting the 
 pulse. But most physicians were content to observe the 
 patient and question him, feel his skin and his pulse, watch the 
 blood which they freely drew from his veins, and observe 
 certain of his excreta. It was inevitable that much skill and 
 cleverness in interpreting the symptoms thus observed had 
 become developed, but it is obvious that advance was pain- 
 fully slow. 
 
 A really valuable contribution to diagnostic aids was made 
 by a medical practitioner of Vienna, named Auenbrugger, 
 who had learned that the resonance of the chest was modified 
 by disease. In order to determine the degree of this reso- 
 nance he proposed the method of percussion, or gentle tap- 
 ping of the chest walls. But it was not until well after the 
 beginning of the nineteenth century that under French in- 
 fluence this method was perfected and extended to the many 
 viscera of the chest and the abdomen. 
 
 Although the ear had previously been employed for listen- 
 ing to certain internal sounds, it was not until 1815 that Laen- 
 nec, a Parisian physician, devised the stethoscope, by which 
 the sounds caused by the beating of the heart, the passage of 
 the air to and from the lungs, and other internal movements 
 can be heard. This was the beginning of the invaluable 
 method of auscultation. Oliver Wendell Holmes, who had 
 the good fortune to study medicine in Paris, was one of the 
 first in this country to recognize the value of the new dis- 
 covery, and in 1836 won a prize offered for the best disserta- 
 
THE NATURE OF DISEASE 33 
 
 tion on "How far are the external means of exploring the 
 condition of the internal organs to be considered useful and 
 important in medical practice?" Dr. Holmes' success, 
 however, did not prevent him from writing also his far less 
 serious poem entitled, "The Stethoscope Song," in which his 
 scientific hero, fresh from the Parisian clinics, came to grief 
 because of the strange diagnoses he made through the aid 
 of his new-fangled instrument, in which "a couple of very 
 impertinent" and very buzzy flies had chanced to make their 
 abode. The stethoscope has gradually imdergone improve- 
 ments, and to-day is the indispensable aid of every physician. 
 Through the addition to it of a microphone and a dehcate 
 galvanometer it has recently become possible to make per- 
 manent photographic records of physiological sounds, and 
 thus to make detailed analyses of them. 
 
 Equally indispensable has become the clinical thermometer 
 for the exact determination of bodily temperatures, especially 
 in fevers. Its universal introduction was likewise one of the 
 achievements of the last century. 
 
 Of great value also was the ingenious invention of the 
 ophthalmoscope in 1851, by the German physicist, Helm- 
 holtz. This instrument made possible for the first time the 
 illumination of the interior of the eyeball, and thus facilitated, 
 not only a physical examination of that organ, but through it 
 the detection of certain constitutional diseases. The princi- 
 ple of internal illimaination has been extended, until there are 
 few organs possessing external orifices that cannot thus be 
 explored. The latest achievement by means of illumination, 
 the echoes of whose initial success have not yet died away, is 
 the discovery by Roentgen of the penetrating power of the 
 X- or Roentgen rays. These rays, transmitted by certain 
 tissues and held back by others, are now used, not only for 
 
 D 
 
34 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 localizing foreign bodies, such as bullets, and in the study of 
 the bones, but also for the observation of pathological condi- 
 tions in various other organs, such as the heart, the lungs and 
 the stomach. 
 
 The labors of physiologists to determine the facts of the 
 circulation of the blood have been richly productive for 
 pathology and practical medicine. These labors are now 
 coming to fruition in the matter of diagnosis. The heart's 
 activity is accessible to observation through various devices. 
 I have already referred to the stethoscope, which is used in 
 transmitting heart sounds either to the ear or to a photo- 
 graphic plate. Like other organs, the heart in action con- 
 stitutes an electric battery, and with each beat its different 
 parts are the seat of differences in electrical potential. These 
 differences may be detected even on the surface of the body 
 by a delicate galvanometer. The instrument most com- 
 monly used contains an excessively fine thread of quartz or 
 platinum, suspended between magnets. When two points 
 on the surface of the body, such as two hands, or a hand and 
 a foot, are placed in circuit with the thread, it bends from side 
 to side with each heart beat. These motions may be photo- 
 graphed, and thus an exact, graphic record may be obtained 
 of the electrical changes involved in the heart's action. 
 Normal hearts make normal records. Pathological hearts 
 make records corresponding to their abnormalities, and thus 
 a new clue is obtained to the presence and the nature of dis- 
 eased conditions. That this method is not merely a scien- 
 tific curiosity is proved by the fact that it is now being in- 
 troduced into hospitals and clinics" as a practical diagnostic 
 aid. It is not necessary that the galvanometer be in the 
 immediate presence of the patient. Accurate records of the 
 heart beat have been transmitted through electric wires for 
 at least one mile and a half. 
 
THE NATURE OF DISEASE 35 
 
 The beat of the heart can be readily observed through va- 
 rious movements of the surface of the body. The most 
 widely recognized of these movements is that of the pulse, 
 which is the wavelike impulse given by the heart in its con- 
 tractions to the blood in the arteries. The pulse can be 
 detected in many arteries, but most conveniently in the radial 
 artery of the wrist, where it not only can be felt by the finger, 
 but often causes a perceptible rise and fall of the surface of 
 the skin. The heart beats are also appreciable in the jugular 
 veins, which lie near the surface at the neck; while the mus- 
 cular walls of the chest on the left side between the fifth and 
 sixth ribs and outside the lower end of the heart receive an 
 impulse directly from the heart itself. Nearly fifty years 
 ago a French physiologist, Marey, devised a delicate instru- 
 ment by which these various movements can be magnified 
 by a lever and be recorded in a graphic manner on paper. 
 This instrument he called the sphygmograph, which means 
 literally "wave writer," and its self-written record is the 
 sphygmogram. From the records of these various move- 
 ments much can be learned regarding the physical condition 
 and movements of the heart and arteries and their state of 
 health or disease. The difficulties of interpreting the details 
 of sphygmograms, which are great and have not yet been 
 wholly removed, and the large amount of experience that is 
 required with the instrument, have prevented its imiversal 
 use. 
 
 Another instrument for the exact study of the condition of 
 the blood-circulatory system, however, is winning favor. 
 Through the investiigations of physiologists on the bodies of 
 animals, it is known that the blood exists in the arteries under 
 a considerable degree of pressure. The amount of this pres- 
 sure depends on the force of the heart beat, the physical 
 
36 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 characteristics of the arterial walls, the degree of resistance 
 to the blood flow that is offered by the small arteries and 
 capillaries, and other factors. The walls of the arteries are 
 richly provided with nerves, through which a particular por- 
 tion of the brain can control the caliber of the vessels and 
 thus can control in some degree the pressure of the blood. 
 This system of nervous control is known as the vasomotor 
 system. We recognize a vasomotor center in the brain, and 
 two kinds of vasomotor nerves, called respectively vaso- 
 constrictor and vasodilator. The caliber of the arteries and 
 therewith the blood pressure in a particular part of the body 
 can be altered through the vasomotor nervous mechanism 
 in accordance with the amount of blood required by that part 
 at a given time. The system is very perfectly organized and 
 works with a degree of exactness that might be expected of a 
 mechanism that has taken many thousands, or even millions, 
 of years to become perfected. The blood pressure varies not 
 only with varying physiological states, but with a great 
 variety of diseased conditions as well. It is obvious that a 
 determination of the degree of blood pressure affords valuable 
 insight into the internal mechanism of the body and its vary- 
 ing conditions. Early in the eighteenth century the Reverend 
 Stephen Hales, rector of a country parish in the south of 
 England, was possessed of a curiosity to investigate many odd 
 and unknown things in nature. Among other strange achieve- 
 ments, he succeeded in measuring the pressure exerted by the 
 blood in the arteries of the horse. This experiment, singular 
 as it must have seemed to his unscientific contemporaries, 
 was the forerunner of great things. Through the perfection 
 of vivisectional methods it has since been possible to make 
 very exact determinations of arterial pressure in animals, but 
 it is only during the past fifteen years that means have been 
 
THE NATURE OF DISEASE 37 
 
 found by which similar determinations are possible in the 
 intact bodies of living human beings. Instruments, called 
 sphygmomanometers, now exist which can be taken directly 
 to the bedside, and by which the accurate measurement of 
 the blood pressure in the patient's arteries can be quickly 
 made. The use of such instruments reveals that inferences 
 regarding the state of the blood-circulatory organs, which are 
 drawn from feeling the throbbing artery with the unaided 
 finger, may be inexact and often quite misleading. The ad- 
 vantages of the new method are so great that the intelligent 
 physician can hardly fail to add the ^new applicance to his 
 constantly increasing equipment. 
 
 I have mentioned but a few of the instruments of precision 
 of which the modern physician makes use. The list might be 
 indefinitely extended to include the elaborate electrical ap- 
 pliances, by means of which the irritability of muscles and 
 nerves, paralysis, and many other affections of the nervous 
 system are detected, the various instruments for testing the 
 delicacy of sight, hearing, and other special senses, and so on. 
 I had almost forgotten to speak of the microscope, without 
 which modern medical practice would be impossible. The 
 universal use of the microscope as an aid to diagnosis was 
 made possible by the discovery of a method of eliminating 
 the color effects due to the chromatic aberration of the early 
 lenses. Efficient achromatic objectives were first made in the 
 third decade of the nineteenth century. With their aid the 
 physician recognizes disease germs and the characteristics 
 of diseased tissues, numbers the corpuscles of the blood, and 
 in innumerable ways augments many thousand fold the 
 powers of his unaided eye. 
 
 If the twentieth-centiu-y diagnostician has thus become a 
 physicist, he is perhaps even more a chemist. Physiological 
 
38 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 chemistry or biochemistry is largely the growth of a single 
 generation, but its accumulations are exceedingly abundant, 
 and they have been promptly utilized for the service of medi- 
 cine. We now know much concerning the play of the atoms 
 and molecules within the body and how they misbehave dur- 
 ing disease. These activities, both normal and pathological, 
 are reflected especially in the various liquids which are con- 
 tained within the body or are given off from it. The blood 
 and the urine are the most significant of these for diagnostic 
 purposes. With both of these liquids both chemical and 
 physical abnormalities frequently signify, not merely that the 
 liquids themselves, or the organs that are immediately con- 
 cerned in their preparation, are at fault, but that organs or 
 tissues remotely concerned with their preparation are abnor- 
 mal. Moreover, they often indicate, in addition to the 
 specific diseases of specific organs, more general metaboUc 
 diseases. 
 
 While the days of medieval blood-letting are fortunately 
 passed, it has been found that even a few drops of blood, 
 following the pricking of the skin by a needle, are sufficient 
 to give clues to the presence of a considerable number of 
 maladies. The determination of the amoimt of hemoglobin, 
 the red coloring matter of the blood, or of the number of red 
 corpuscles, is valuable in detecting such affections as the 
 various forms of anemia, which in turn may be indicative of 
 the presence of other diseases. The amount of hemoglobin 
 present in the blood of anemic individuals may be only 
 fifteen or twenty per cent of the normal amount. Mere 
 pallor of the skin, which may be present in anemia, may also 
 be due to other causes and does not necessarily indicate an 
 anemic condition. The average number of leucocytes in 
 one cubic millimeter of the blood of healthy persons varies 
 
THE NATURE OF DISEASE 39 
 
 between 5000 and W,000. In certain diseases it may far 
 exceed these figures, in others it may be far less. Thus, in 
 pneumonia the number of leucocytes is frequently as many 
 as 40,000 or more, while in typhoid fever there is usually a 
 diminution below the normal. The relative frequence of 
 the several varieties of the corpuscles is also significant. 
 Bacteria and other parasites are frequently found in blood. 
 It has recently been discovered that the blood serum of per- 
 sons suffering from typhoid fever, when added to a Hquid con- 
 taining living typhoid germs, causes the latter to cease moving 
 and to aggregate together La crowds. This pecuhar phe- 
 nomenon is the basis of a new test for the presence of typhoid, 
 the Widal test, which has proved a most valuable addition to 
 diagnostic methods. One of the greatest advances has been 
 along the lines of the new physical chemistry. The degree 
 of molecular concentration of the blood, or, in other words, 
 the relative number of molecules and ions contained within 
 it, is significant. Recent work has shown that this can be 
 determined by the comparatively simple procedure of ob- 
 serving at what temperature the serum, or Hquid portion of 
 clotted blood, freezes. Healthy blood serum freezes at ap- 
 proximately — .56° C, i.e. half a degree lower than the point 
 at which pure water freezes. If, however, the freezing point 
 is found to be lower than the normal, the blood contains too 
 large a proportion of solids, and the inference is justified that 
 the kidneys are not performing their full function. 
 
 While the physical and chemical characteristics of the 
 urine constitute the key to certain maladies of the kidneys; 
 their significance reaches far beyond that organ, by reason 
 of the fact that the urine represents a most important me- 
 dium, in which the tissues of the whole body eliminate both 
 normal and abnormal material. There are few tissues which 
 
40 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 do not exhibit through the urine their functional peculiarities. 
 Not only the kidneys, but the liver, the heart, the muscles, 
 the digestive and other organs, thus reflect their state of 
 health or disease. A most elaborate science has therefore 
 grown up around the study of this one product of bodily 
 activity. Of significance as diagnostic aids are the amount of 
 the urine; its specific gravity; its freezing point and hence its 
 molecular concentration; its color; its acid or alkaline reac- 
 tion ; its content in nitrogen, as well as urea, uric acid, vari- 
 ous proteins, pigments, sugars, and other organic compoimds, 
 as well as various inorganic constituents ; and the presence 
 of blood, of crystals of various kinds, of bacteria, of body 
 cells and of "casts," a pathological product, visible to the 
 microscope, and formed in the minute secreting tubes of the 
 kidney. 
 
 However skillful diagnosis has become, it often makes 
 mistakes. It often happens that derangements do not reveal 
 themselves until long after they ought to be attended to. 
 Now and then the combination of symptoms simulates some- 
 thing different from that which is really present. At times 
 the best of doctors disagree as to the interpretation of symp- 
 toms. A well-known and learned American physician has 
 recently published results of a courageous study of mis- 
 taken diagnoses, which was based on a comparison of the 
 conditions as indicated by clinical observations and the con- 
 ditions as actually revealed by the autopsies of the same pa- 
 tients. It is a valuable contribution to the literature of 
 medical errors. At the same time it reveals the present 
 hopeful attitude of the best of the medical profession. The 
 physician has never before appreciated so keenly the necessity 
 of correct diagnosis. If in the past he has done those things 
 which he ought not to have done, and confessed his faults 
 
THE NATURE OP DISEASE 41 
 
 in the proper spirit of humiliation and repentance, his mis- 
 takes hereafter will be fewer in number. And they are daily 
 becoming fewer. The sharp, critical analysis of diseased 
 conditions and their prompt detection are two of the promi- 
 nent features of modern medicine, and largely contribute to 
 its right to be called scientific. 
 
Ill 
 
 METHODS OF TKEATING DISEASE 
 
 In the two previous lectures we have considered normal 
 structure and function and some of their perturbations in 
 disease. We are continually beset by agencies, powers of 
 pathological darkness, without and within, which, if unop- 
 posed, would turn us from the straight and narrow path of 
 health and lead us into chaos. We may oppose these evil 
 agencies in two ways : either through our innate powers of 
 resistance, or by recourse to the help which medical science 
 offers. In the present lecture I wish to consider these two 
 methods of combating disease. 
 
 Physicians used to speak of the vis medicatrix naturoe, the 
 healing power of nature. The phrase expressed an idea as 
 mystical as that of vis vitalis. We no longer use the words, 
 but the principle persists. Modern medicine has analyzed it 
 and now terms it the natural defenses of the organism 
 against disease. Darwin has drawn a graphic picture of the 
 struggle that, to preserve their existence, living organisms 
 wage against other living organisms. Every variation in 
 structure or function that gives one the advantage over 
 another tends by so much toward the preservation of the 
 one and the destruction of the other. Nature is ever se- 
 lecting her favorites and endowing them with special gifts. 
 They survive, while their rivals perish. By the inheritance 
 and accumulation of beneficial variations the organism be- 
 comes constantly more complex and better adapted to cope 
 
 42 
 
METHODS OP TREATING DISEASE 43 
 
 with the conditions of existence. Fifty years after the pub- 
 lication of the "Origin of Species" biology is questioning in 
 how far natural selection is a factor in organic change. But 
 whatever the cause, the fact is not to be denied that in the 
 course of evolution the internal mechanisms of organisms 
 have become more efficient in meeting the many vicissitudes 
 to which they are subject. Accidents and disease are promi- 
 nent among these vicissitudes, and against them organisms 
 are provided with many natural means of defense. It is 
 worth our while, I think, to consider these provisions of 
 nature, before going on to discuss the various artificial agen- 
 cies which man makes use of in his fight against disease. 
 
 Nature has been generous to the human race. With eyes, 
 ears, hands, lungs, kidneys, and various other glands she has 
 given us a double equipment, and even if one organ of each 
 pair be lost, the cripple's powers of life are not seriously im- 
 paired. Tuberculosis may destroy one lung, and the other, if 
 it be healthy, will take in oxygen and give out carbonic acid 
 in the same quantities which formerly passed through the 
 two organs together. The surgeon knows that if to save a 
 patient's life, he must remove a diseased kidney, the other 
 kidney, if healthy, will at once begin to perform the functions 
 of both, and with rapid growth in size and amount of secret- 
 ing tissue, will soon become capable of double labor. It has 
 recently been shown that the thyroids and the adrenal bodies 
 are profoundly related to certain bodily processes. The total 
 removal of thyroid tissue causes serious physical and mental 
 abnormalities, yet these are obviated if even one fifth of the 
 tissue is left. The total removal of both the adrenal bodies 
 is followed by speedy death, but serious results are averted 
 if even a mere fragment of one be left. Similar lavish gener- 
 osity of tissue is exhibited by unpaired organs. Surgical 
 
44 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 experiments on animals have shown that in them one half or 
 three fourths of the liver and nine tenths of the pancreas 
 may be removed without endangering life. Surgeons have 
 removed from man's body without fatal results, parts of or 
 even the entire stomach, or considerable portions of the in- 
 testine. Certain portions of the brain which control certain 
 bodily movements may be removed without the serious im- 
 pairment of these movements, since other portions of the 
 brain seem to be capable of performing the work of the lost 
 parts. Nearly one half of the blood may be lost without per- 
 manently serious effects. In certain cases similar labors are 
 carried on by anatomically different organs, and the loss of 
 one does not mean that the body is wholly deprived of the 
 common function. Thus if a person closes his eyes and at- 
 tempts to walk, he will be dizzy and uncertain in his move- 
 ments. This simple experiment teaches him that customarily 
 his eyes are an aid in the maintenance of his bodily equilib- 
 rium. With blind persons other senses must perform the 
 entire work of indicating to the brain the equilibrium needs 
 of the body. Both the gtomach and the pancreas produce 
 ferments that are capable of digesting proteins, and the. 
 salivary glands and the pancreas others that digest starches. 
 Allied to these instances of the generosity of nature are 
 cases of adaptability to changed conditions. In accordance 
 with our bodily needs our heart beats rapidly or slowly ; we 
 breathe more or less rapidly and more or less deeply — thus 
 in fever we automatically breathe rapidly and thus en- 
 deavor to keep down our abnormal temperature ; our vari- 
 ous arteries become constricted or dilated ; we contract oxir 
 muscles to a greater or a less degree ; we use for mechanical 
 purposes more or less of the energy of our food ; we produce 
 and eliminate more or less heat — if we are cold, we shiver to 
 
METHODS OF TREATING DISEASE 45 
 
 warm ourselves ; and we either oxidize our food at once or 
 store it for future needs. In the course of normal activity 
 we produce various chemical substances which are poisonous 
 to protoplasm and, if allowed to accumulate, would be dan- 
 gerous to health. Our bodily adaptability is such, however, 
 that our tissues promptly seize upon these substances, and 
 by chemical combination render them innocuous. If bac- 
 teria enter the body, the harmful toxins that they give off 
 stimulate our cells to produce antitoxins, and by a union of 
 the two the bacterial products are made harmless ; or anti- 
 bacterial substances are produced, which destroy the invad- 
 ing germs. If a cut in the skin brings the blood, it promptly 
 clots at the wounded spot and further hemorrhage is avoided. 
 The value of this power is sadly demonstrated by those un- 
 fortunate persons in whose bodies the essential factors in 
 blood coagulation are wanting, and a trifling wound allows 
 their vital fluid slowly to ooze away. 
 
 The natural defenses of the body against disease are no- 
 where more strikingly shown than in the leucocytes, or white 
 blood corpuscles. It was the French biologist, Metchnikoff, 
 the present sous-directeur of the Pasteur Institute in Paris, 
 who first claimed that the true worth of the leucocytes had 
 never been recognized. In a body suffering from an invasion 
 of bacteria he noticed that many of the microbes were in- 
 closed within the bodies of the white blood cells. He in- 
 vestigated the phenomenon, and was led to the idea that one 
 of the duties of leucocytes is to destroy bacteria, many of 
 which are the germs of diseases, by deliberately engulfing, 
 killing, and digesting them, and thus to protect the body 
 from the foreign invaders. To the cells engaged in this work 
 he gave the name phagocytes, signifying eating cells, and to 
 the process phagocytosis. It is now agreed that Metchnikoff 
 
46 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 discovered here a phenomenon of wide occurrence and of the 
 greatest value to the individual. To leucocytes, further- 
 more, have been ascribed the production and elimination of 
 chemical substances which are poisonous to bacteria and kill 
 them without previous ingestion. Thus in two ways are the 
 white blood cells inimical to our organic enemies. Many of 
 them accumulate at the parts of the body which are the 
 natural ports of entry of the foreign cells, such as in the walls 
 of the air passages, along the alimentary canal, and wherever 
 the skin is cut or injured. They there form an advance 
 guard to repel invaders. If this guard is overpowered, there 
 still exists the main force of leucocytes scattered throughout 
 the organism and ready to pounce upon the aliens wherever 
 found — and woe betide the luckless germ that actually 
 enters the tissues ! Leucocytes are ever ready to give up 
 their lives to duty, and large numbers are destroyed daily, to 
 be replaced by new ones born in the lymphatic glands and 
 the marrow of the bones. Little do we realize what watch- 
 ful defenders are constantly, day and night, caring for our 
 personal safety.' 
 
 I have mentioned but a few of the numerous protective 
 provisions of nature with which our bodies are endowed. 
 Our power of ready and harmonious physiological adapta- 
 tion to our environment in the interests of ourselves is one 
 of the most valuable of our possessions. It has become cus- 
 tomary to deride the idea of teleology, but however unsci- 
 entific the teleological point of view of a half century ago 
 appears now, the fact of the .protective adaptation of or- 
 ganic means to environmental conditions cannot be denied. 
 Through our innate powers our bodies are constantly endeav- 
 oring, whether we wish it so or not, to maintain their health 
 1 See also pp. 77 and 79. 
 
METHODS OF TREATING DISEASE 47 
 
 and ward off disease and death. We are inclined, I think, to 
 underestimate both the numbers of the hostile agencies sur- 
 rounding us and our powers of resistance. 
 
 But there come times in the experience of all of us when our 
 own powers prove inadequate, and it is then that if we are not 
 beguiled by the seductive words of quackery, we turn for aid 
 to the physician and his science and art. We can only 
 surmise regarding the beginning of the art of healing, for 
 the earliest historical records give evidence of its preexistence. 
 Since even animals are known to employ healing methods, as 
 is illustrated by the facts that cats and dogs lick their wounds 
 and monkeys try with their paws to stop a flow of blood, it is 
 probable that primeval man inherited certain curative in- 
 stincts. His subsequent medical acquisitions imdoubtedly 
 originated largely in empiricism, the experience of individuals 
 in securing relief from pain and physical discomfort. Crude 
 empiricism indeed has given us a great portion of the medical 
 art down to the nineteenth century, and it has not yet disap- 
 peared. It was early joined by magic, and magic's healthful 
 amulets are still seen in the rabbit's foot and the horse- 
 shoe, which ward off witches and bring good luck, and in the 
 potato that is still carried in the pocket to cure rheumatism. 
 In the division of labor among the people of a race the art of 
 healing was early assumed by specific individuals — the 
 savage tribe of the present time has its medicine man. With 
 the appearance of religions priests took over the art in some 
 degree, but even in early Greek times the medical profession, 
 distinct from the priesthood, existed, and it has gradually 
 acquired a position of constantly increasing authority. 
 
 The scientific physician of to-day makes use of, and in so 
 far as he is able, reenforces the patient's natural means of 
 defense. But he supplements these by a host of agencies, 
 
48 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 the sum of which in his pedantic moments he is pleased to call 
 his armamentarium. Besides the surgical methods he em- 
 ploys for therapeutic purposes drugs, foods, water, serums, 
 vaccines, electricity, heat and cold, mechanical agents, rest, 
 exercise, massage, climate, mental influences, and, in fact, 
 whatever physical, chemical, and psychical agencies seem to 
 be helpful. I shall devote the remainder of this hour to a 
 consideration of some of these measures. 
 
 Drugs, which may be of vegetable, animal, or mineral ori- 
 gin, constitute one of the most ancient and universal of all 
 of the material agencies employed by man for his manifold 
 purposes. There never has been a period in human history 
 when they have not been known. They have been cele- 
 brated in love potions and as holding the secrets of per- 
 petual youth; in magic and superstition they have been 
 indispensable ; in political intrigue they have been potent ; 
 and in the treatment of diseases no agent has been more 
 resorted to. Primitive knowledge of the action of drugs was 
 doubtless obtained chiefly from crude empiricism. In the 
 Middle Ages the curious doctrine of "signatures" arose, and 
 its contributions to materia medica are still influential in 
 popular medicine. According to this, the Creator placed 
 signs upon natural objects to indicate to men their uses. 
 Thus, from the fact that the leaflets of Oxalis are heart- 
 shaped, it was believed that they were effective in diseases 
 of the heart. The resemblance of the "fibers" of the hepatic, 
 Marchantia, to the "fibers" of the liver signified that this 
 plant is to be employed in diseases of the liver, hence the name 
 liverwort. We can trace similar notions in the common plant 
 names, lungwort, kidneywort, and maidenhair. Adder's 
 tongue cured the bites of snakes, and yellow flowers jaundice. 
 A garden was thus full of evidence of God's care of man. 
 
METHODS OF TREATING DISEASE 49 
 
 The doctrine was carried to great lengths. The seventeenth- 
 century herbarist, William Coles, author of "Adam in Eden : 
 or Natures Paradife," relates that "Wall-^uts have the perfect 
 Signature of the Head : The outer husk or green Covering, 
 reprefent the Pericranium, or outward skin of the skull, 
 whereon the hair groweth and therefore fait made of thofe 
 husks or barks, are exceeding good for wounds in the head. 
 . . . The Kernel hath the very figure of the Brain, and there- 
 fore it is very profitable for the Brain, and refilts poysons ; 
 For if the kernel be bruifed, and moyftned with the quintef- 
 fence of Wine, and laid upon the Crown of the Head, it com- 
 forts the brain and head mightily." 
 
 The exact study of the actions of drugs did not begin imtil 
 the nineteenth centiu-y, the first laboratory for their investi- 
 gation having been established in Dorpat in 1856. In the 
 fifty-five years that have elapsed since then, the science of 
 pharmacology has arisen. The day of "simples" has nearly 
 passed, however much we may regret it who recall our grand- 
 mothers' attics with their bundles of smelly herbs. An herb 
 in the attic, it must be confessed, brings up sweeter memories 
 than its decoction, for camomile, spearmint, sage, and hem- 
 lock used to send the cold shivers running up and down our 
 little spinal colunans. But our grandmothers' simples are 
 really composites. In 1817 morphine was extracted from 
 opium. This was the first of the active principles of drugs to 
 be made known, and now active principles take the place of 
 the former crude mixtures. Other examples of active princi- 
 ples that have been isolated from the crude drugs are strych- 
 nine from nux vomica, quinine from cinchona, and atropin 
 from belladonna. Official standards of purity now exist in 
 most civilized countries and are recorded in the national 
 pharmacopeias. Our knowledge of the actions of drugs on 
 
50 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 living substance has been placed upon an exact basis. For- 
 merly if one wished to know experimentally the action of a 
 drug, he administered it to his fellow-men or, in some cases, 
 to animals, and watched the effect. The great Mithradates, 
 king of Pontus, is said to have been so inconsiderate as to 
 study the actions of poisons upon his relatives, but lest we 
 blacken his character too deeply, it should be added that he 
 also experimented upon them with antidotes. A modern 
 pharmacologist, aware of the extraordinary complexity of the 
 body, realizes that experimentation on the human body is 
 crude and inexact, and therefore proceeds by refined methods, 
 which constantly become more refined and approach ever 
 nearer a mathematical ideal of exactitude, to examine the 
 action of known quantities of the drug on the functions of 
 each of the individual organs or tissues of the animal body, 
 isolated as far as posisible from the other organs or tissues. 
 This is supplemented by a similarly exact study of the be- 
 havior of combinations of organs or tissues under the in- 
 fluence of the drug. Still further experiments, performed 
 outside of the hving tissues, relate to the influence of the 
 drug on the chemical reactions of various organic and in- 
 organic substances. By the aid of these analytical proce- 
 dures the pharmacologist accumulates a fund of data, 
 equipped with which he can observe and interpret under- 
 standingly the action of the drug on the intact human body 
 and can suggest its rational use in disease. Such methods as 
 these have now been applied with more or less completeness 
 toward the perfecting of a knowledge of the action of the 
 older drugs, and no one of the newer remedies is employed 
 without similar careful, preliminary experimental studies. 
 The practical result is a vigorous reform of drug treatment. 
 Physicians no longer administer the old mixtures of innumer- 
 
METHODS OF TREATING DISEASE; 51 
 
 able drugs, given with the comprehensive hope that some one 
 component would hit the mark, and hence called "shot-gun" 
 prescriptions. Large quantities of individual drugs also are 
 avoided, and the endeavor is made to reach only the specific 
 functions that are disordered. 
 
 Drugs affect living substance in one of two ways : either 
 by increasing or by diminishing its natural activities. Thus, 
 digitalis stimulates to greater contraction the muscle tissue 
 in the walls of the arteries, and thus increases the blood 
 pressure — at least in animals. Amyl nitrite, on the other 
 hand, depresses these muscles and diminishes the blood 
 pressure. In medicinal doses digitalis makes the heart beat 
 more slowly, but it does this, not by depressing the heart 
 muscle, but rather by stimulating the nervous mechanism 
 whose normal action is to slow the heart. Atropin, however, 
 an active principle of belladonna, quickens the heart by lessen- 
 ing the activity of the same nervous mechanism. Many 
 drugs at first stimulate and then depress. 
 
 Drugs rarely affect similarly all the various kinds of cells 
 in a body or indeed all the functions of the same cell. Thus 
 strychnine seems to have a special predilection for the spinal 
 cord and medulla oblongata, and within those parts it prob- 
 ably acts upon the incoming nervous paths rather than the 
 outgoing. Quinine, on the contrary, seems to have no such 
 choice, but affects nearly alike all kinds of the body's proto- 
 plasm. These selective pecuharities of drugs are a great aid 
 to the physician, for they often enable him to reach a desired 
 tissue with great exactness and without interfering with other 
 tissues. They have never been so clearly demonstrated as 
 in certain of the infectious diseases, i.e. diseases in which the 
 causative agent is a specific living organism, such as a bac- 
 terium or a protozoan, which has invaded the body. It is 
 
52 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 obvious that in such a case the ideal drug would be one that 
 would kill the parasites without injuring the patient. In 
 several cases such drugs have been found. Quinine is such a 
 specific for malarial germs. A compound of arsenic, atoxyl, 
 has been found to be partially effective with the deadly- 
 African scourge, sleeping sickness; and still more effective 
 bids fair to be a derivative of atoxyl, called arseno-phenyl- 
 glycin. The most recent triumph of this nature is in the 
 treatment of syphilis, which has been announced within a 
 few months. This loathsome disease, the ultimate fate of the 
 personally immoral, and terrible in its physical effects, dates 
 from prehistoric times, and is perhaps the most widely 
 distributed of all the major diseases. It is due to the ravages 
 of a microscopic organism called Treponema pallidum, which 
 possesses some of the characteristics of both bacteria and pro- 
 tozoa. Its body consists of a single cell, spiral in shape. It 
 occurs within the tissues and within the blood of the infected 
 human body. A few years ago Professor Paul Ehrlich, the 
 director of the Royal Institute for Experimental Therapeu- 
 tics at Frankfurt-on-the-Main, who has made very brilliant 
 discoveries of value in both theoretical and practical pa- 
 thology, began a search for a drug which should prove to be 
 a specific for this organism. After investigating more than 
 six hundred substances he found that the six hundred and 
 sixth, a peculiar compound of arsenic, possesses, in many 
 cases, the desired properties, namely, that of seeking out 
 each and every Treponema in the body of the afflicted person 
 and destroying it without injuring in any manner the body 
 cells. Although the drug is not effective in every instance, it 
 frequently happens that a single dose accomplishes the de- 
 sired result. The popular name of this drug is 606, its 
 medical name salvarsan, its chemical name dioxy-diamido- 
 
METHODS OP TREATING DISEASE 63 
 
 arseno-benzol. Ehrlich's work is prophetic of still greater 
 possibilities, for if specific poisons have thus been discov- 
 ered for two or three disease germs, we may confidently look 
 for similar modes of treatment for others. It is possible 
 that such specific chemicals will prove to be the medium 
 of our final salvation from the infectious diseases. 
 
 Even when all the body cells are ultimately affected by a 
 drug, it usually happens that some cells are more susceptible 
 to it than others. This makes possible the practice of 
 anesthesia. An anesthetic, like ether or chloroform, is a de- 
 pressant of living substance ; when its administration is con- 
 tinued, it diminishes and may ultimately put a stop to vital 
 action and cause death. It acts upon all kinds of protoplasm 
 and all varieties of cells and tissues, but in the early stages of 
 its administration its action is more obvious upon the brain 
 than upon other parts. Within the brain it depresses first 
 those cells whose activities are accompanied by consciousness 
 and therefore by the recognition of pain. Next in order 
 of paralysis comes the spinal cord, which contains the central 
 nervous mechanism of most of our bodily movements. And 
 lastly comes the medulla oblongata, in which lies, among 
 other important nervous centers, that center which maintains 
 respiration. The successful administration of an anesthetic 
 for a surgical operation demands that just so much of the 
 drug be given as is required by the brain cells and the cells 
 of the spinal cord to banish consciousness and the power of 
 making bodily movements. With any amount beyond this, 
 anesthesia approaches the danger point of stopping the 
 breathing or the heart. 
 
 Much attention is now being given to the problem as to 
 how drugs exert their action. How do they stimulate or 
 depress protoplasm? This problem is a difi&cult one, and 
 
54 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 ' its solution has hardly gone beyond the stage of hypothesis. 
 It seems probable, however, that in many cases of drug 
 action, if not in most, there is a chemical union between the 
 drug and certain constituents of the cells. In some cases we 
 can probably go even farther than this and link the reaction 
 with specific parts of the molecules, or with the ions of the sub- 
 stances in question, or with the arrangement of the atoms 
 within the molecule. If chemical union does occur, a selec- 
 tive action of a particular drug for a particular group of 
 cells may be readily explained by supposing that such cells, 
 and not others, contain particular chemical substances for 
 which the drug has an affinity. In other cases the action of 
 the drug is rather physical than chemical. Thus the sub- 
 nitrate of bismuth, when taken into the stomach, forms an 
 insoluble lining and thus protects the gastric walls from in- 
 jurious agencies. 
 
 The ultimate fate of a drug varies with the variety of 
 drug. Some drugs, for example, adrenalin, are actually 
 destroyed by the tissues. Others are eliminated by the excre- 
 tory organs, such as the kidneys, though in some cases this 
 process is very slow. Thus, after a course of treatment with 
 mercury the drug may be found in the body for two or three 
 months. 
 
 A special division of drug therapy which has arisen in very 
 recent years is that in which animal organs or preparations 
 from such organs are administered in cases in which the 
 analogous organs in men are wanting, are insufficiently de- 
 veloped or are diseased. In all of these cases the organs in 
 question supply to the body an internal secretion which 
 exercises a profound action on bodily metabolism, and the 
 absence of which is followed by equally profound phenom- 
 ena. So far the greatest success has attended such use of 
 
METHODS OF TREATING DISEASE 55 
 
 the thyroid glands in myxedema and cretinism. The many 
 claims that have been made of the benefits following the ad- 
 ministration of material from other organs must, at present, 
 be received with caution. 
 
 Notwithstanding the many and varied improvements in 
 drug therapy in recent years, it is undoubtedly a fact that 
 with the development of other methods of dealing with dis- 
 ease, physicians are depending less than formerly on the 
 conventional drugs. But there is truth in the words of the 
 French clinician, "Medicine sometimes cures, it often re- 
 lieves, it always consoles," and it will always continue to be 
 used for all of these three purposes. 
 
 High hopes have been raised in the minds of some men of 
 medicine that the newly discovered rays of various kinds will 
 prove valuable in the treatment of disease. Roentgen rays 
 and the emanations of radium have been turned to with the 
 enthusiasm of expectant success. The physiological actions 
 of these two agents are practically identical and, vary with 
 the intensity of the radiations. When they are weak they 
 stimulate, when stronger they depress and may kill the living 
 cells. Diseased tissue and pathological growths, such as 
 tumors, seem to be more sensitive to the radiations than 
 normal tissue. Sometimes the physician makes use of the 
 stimulating action, and sometimes, as in tumors, the destruc- 
 tive action. The intensity of the dose of radiations should 
 be carefully graded in accordance with the end desired and 
 the variety of tissue dealt with. The selective action of the 
 radiations on the different tissues is now becoming known, 
 and the destructive burning which occurred with the early 
 use of these agents can now usually be avoided. X-rays 
 have been extensively used in diseases of the skin, and by 
 both X-rays and radium certain tumors have undoubtedly 
 
56 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 been cured. In a few other diseases specific symptoms have 
 often been alleviated, but the limits of radiotherapy in general 
 are not yet determined. j 
 
 The therapeutic benefits resulting from proper bathijig 
 are now being emphasized more than ever before. These 
 consist not merely in the cleansing of the skin, for that is 
 presupposed; nor in the employment of medicated waters, 
 for the absorption of such medicaments through the skin in 
 such conditions does not occur ; but largely in the fact that 
 water is a most suitable medium for conveying heat, cold, 
 and mechanical stimuli to the sensory nerve-endings in the 
 skin. Afferent nervous impulses are thus produced, which 
 in turn lead to beneficial reflex effects throughout the body, 
 on the heart, the arteries, the respiratory organs, the nutri- 
 tive processes, the bodily temperature, the distribution of 
 blood corpuscles, the muscles, and the nervous system. When 
 properly regulated these actions may be turned to excellent 
 account in the treatment of various diseases: The cold bath 
 employed in typhoid fever is valuable, less for any direct 
 effect it may have in lowering the temperature, for this is 
 slight, than for its reflex stimulating actioh on the bodily 
 tissues. 
 
 Time forbids a consideration of the maiiy other physical 
 and chemical means of which the physician makes curative 
 use, but we may turn to a method of healing of a different 
 ,type which is of late attracting much attention, both popu- 
 larly and among a considerable number of men of medicine, 
 namely, mental healing or psychotherapy. In all ages, 
 from the most remote to the present, a close relation between 
 mind and disease has been recognized. This relation is not 
 limited to the so-called diseases of the mind, but is conceded 
 to exist for the great mass of both structural and functional 
 
METHODS OF TREATING DISEASE 57 
 
 diseases. In harmony with this belief the mind of the 
 patient has always been one of the channels through which 
 cure has been sought. Of late years, following the applica- 
 tion of the experimental method to the study of mind, where 
 introspection and metaphysical reasoning had long ruled, 
 there is a tendency to introduce psychological principles into 
 orthodox medicine. This has been more pronounced in 
 France and Germany than in England and America, but the 
 tendency is probably spreading. Outside of strictly medical 
 circles there have arisen the cult of Christian Science and 
 many less pretentious groups of healers, with all of whom 
 treatment is based primarily upon psychic influences; 
 and very recently certain long-established branches of the 
 Christian church have come to believe that there exists for 
 them a legitimate sphere of usefulness in the treatment of 
 the sick. 
 
 That physical ills are responsible for mental changes, that 
 the body can influence the mind, is a proposition which no one 
 who has ever experienced physical ills will be disposed to deny. 
 The psychic effect of pain, the hallucinations of fever, the 
 cheerful hopefulness of tuberculosis, — all are well known. 
 One's whole mental make-up may be profoundly affected by 
 disease. "The devil when sick, the devil a monk would be." 
 
 But the truth of the reverse proposition, that the mind 
 can influence the body and directly cure physical maladies, 
 is not so evident. That there is a close relation between 
 psychic states and the activity of parts of the body outside 
 of the central nervous system, has been proved in many ways. 
 Darwin published a volume on the external expression of the 
 emotions in man and animals. Pawlow has found in ani- 
 mals that both the quantity and the composition of the saliva 
 vary, not only in accordance with the presence of different 
 
58 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 kinds of food in the mouth, but with the mere exhibition of 
 such foods, or even with the exhibition of geometrical forms < 
 or with musical sounds which have become associated with 
 particular foods. The watering of the mouth in the presence 
 of delectable foods is thus literally true. Cannon, by ari 
 ingenious use of X-rays, has made in animals a careful study 
 of the movements occurring in the walls of the stomach and 
 intestine during digestion, and has found that emotions, such 
 as fear, distress, and rage, may be accompanied by a total ces- 
 sation of the movements. Peterson has demonstrated a close 
 relation between emotions and electrical currents in the 
 hands. Mosso constructed a delicate balance, on the beam 
 of which a man can lie horizontally. If he is spoken to, the 
 head end of the beam will immediately decline, owing to the 
 passage of blood from his body to his brain. The same 
 change even follows a slight noise occurring during sleep. 
 Because of the demand of the brain for blood, all sorts of 
 mental processes are accompanied by a diminution of the 
 volume of various parts of the body, such as the arm and the 
 ear. But none of these instances of close relationship be- 
 tween mental and corporeal processes demands, by way of 
 explanation, that mind is responsible for bodily actions. 
 
 An unprejudiced reader of the mass of literature that has 
 been poured upon a patient world concerning the relations of 
 body and mind, cannot fail, if he has a sense of humor, to be 
 impressed by its real grotesqueness in the midst of its seri- 
 ousness. A theory is elaborated with great completeness and 
 subtlety of reasoning by one whom we will call philosopher 
 A, and is proposed with a degree of conviction that would 
 seem to win all. Thereupon the equally acute philosopher B 
 proceeds to show by the force of the abundant logic at his 
 command that nothing is further from the truth than A's 
 
METHODS OF TREATING DISEASE 59 
 
 idea, that it is crude and inconceivable and inconsistent with 
 known facts, and that B's conception is the only possible 
 one. Then C enters the arena, and before the brilliance and 
 strength of his arguments, not only does A go down, but B 
 as well. C's hypothesis stands forth victorious, until it, too, 
 is vanquished by the specious dialectician D. Thus we are 
 asked to believe that both body and mind are material, and 
 that they are both immaterial ; that body is the product of 
 mind, and mind the product of body ; that body acts upon 
 mind, that mind acts upon body, and that neither acts upon 
 the other ; that mind has no extension in space, and that it 
 extends as far as thought extends. In such a state of diver- 
 gence of opinions it would seem that a simple pragmatic 
 position is justified, that any theory of the relations of body 
 and mind that proves workable for the individual is in so far 
 true. 
 
 Most physicians of the present time do not incline to- 
 ward dialectic subtleties and do not formulate very exact 
 theories of -the relation of body and mind. In so far as they 
 do so, probably many would incline toward some such notion 
 as was outlined in my first lectiu'e as a convenient working 
 hypothesis for the physiologist.' All cells of the brain, as of 
 other organs, manifest their activity by certain chemical and 
 physical changes: they produce carbon dioxide and other 
 substances, they become warmer, and they are the seat of 
 electrical phenomena. Certain nerve-cells, such as those 
 situated in the cortex of the cerebrum of the brain, mani- 
 fest their activity, not only by the customary chemical 
 and physical changes, but by certain other changes of an 
 unknown nature, which we call psychic. Mind is the 
 sum of these psychic phenomena. Differences in the activ- 
 
 • See p. 18. 
 
60 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 ities of the cortical cells, resulting from corporeal changes, 
 may be accompanied by differences in the chemical, physical, 
 and psychical manifestations of these cells — in other 
 words, body or brain may influence mind. But, just as the 
 carbon dioxide, heat, and electricity are the resultants, not 
 the causes, of the activity of the brain cells, so is the psychic 
 change a resultant and not a cause — in other words, mind 
 cannot influence brain or body. Every action of our nervous 
 system may be likened to a link in a chain of neural or physi- 
 ological processes, which is much branched and ever extend- 
 ing. No one of the innumerable links ever arises de novo; 
 it is always preceded by a past link. It may or may not be 
 followed by a future one : the ends of the chain's spreading 
 branches may be linked to others or may terminate abruptly. 
 But from the beginning of the individual's life to the end of 
 it the chain itself is never broken. Day and night, summer 
 and winter, in season and out of season, our nervous tissues 
 are ever active, and there is ever continuity. Such continu- 
 ity is one of causality; that is, each link is the resultant of 
 those which have preceded it. Most of our neural links are 
 totally unconscious processes, but a few of them during our 
 working hours exhibit the peculiarity which we call mind. 
 Mind is one of the products of neural activity. It is a psychic 
 accompaniment of certain links in a continuous neural chain 
 of cause and effect. Mind is not necessarily continuous, and 
 it is never causal in the sense that one idea can give rise to the 
 next. Such an hypothesis assumes nothing as to the nature 
 of mind. It leaves that for future investigation. "But," 
 an unbelieving critic would say, "your hypothesis would make 
 forever impossible the use of mind as a therapeutic agent." 
 That would seem to be literally true, and yet the methods 
 employed by psychotherapists would still be justified. Many 
 
METHODS OF TREATING DISEASE 61 
 
 of their cures are undoubted. It is only the interpretation of 
 their cures that would be affected. Psychotherapy would 
 still remain a legitimate agent to be employed by the physi- 
 cian. 
 
 In the present stage of the development of psychotherapy 
 one cannot say in how far it will ultimately be used. Most 
 physicians would probably restrict it to a limited range of 
 nervous diseases, the exact anatomical basis of which is 
 unknown. It is generally acknowledged to be of value in a 
 class of diseases to which the general name psychoneuroses 
 has been given. These include neiu-asthenia, psychasthenia, 
 hysteria, and certain conditions bordering on insanity. But 
 these names cover a wide range of disorders associated with 
 organs outside of the central nervous system. Thus neuras- 
 thenia, which is only the modern, new-fangled name for the 
 old malady nervous prostration, may be manifested by 
 muscular weakness, various forms of indigestion, palpitation 
 of the heart, and other disorders of the circulatory functions, 
 deficiency of the various secreted fluids, a great variety of 
 unwonted sensations, such as headache, backache, heat, cold, 
 fatigue, soreness, numbness, weakness, various disturbances 
 of vision, hearing, smell, and taste, abnormal mental phe- 
 nomena and insomnia. Hysteria is a very complex disorder. 
 Like neurasthenia, it may affect many bodily functions. It is 
 specially characterized mentally by a lack of sensations of 
 particular parts of the body, and by weakness of memory and 
 the will. Psychasthenia is characterized preeminently by 
 the presence of fixed ideas, or obsessions. Thus one patient 
 had for years a morbid fear of dust in her room, and would 
 sweep and dust and clean until she became exhausted. Later 
 she devoted hours to the repeated washing of her hands. 
 Here, too, are placed certain fears which many of us possess 
 
62 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 in a very mild form — fears of high places, of open places, or 
 of closed rooms. In such states as these, all of which exhibit 
 pronounced mental peculiarities, psychotherapy in the hands 
 of intelligent, patient, and skillful physicians is frequently of 
 great value. 
 
 Psychotherapeutic methods vary greatly with the individ- 
 ual physician, and there are many grades of complexity in 
 treatment, from that involved in the simple, quiet reassuring 
 manner of the old family doctor, to the long-continued, 
 avowedly psychological treatment, following elaborate psy- 
 chological analyses. Occasionally hypnosis is employed, but 
 this is usually not regarded as necessary. The main factor 
 in the treatment is probably suggestion. Through it old, 
 harmful neural complexes are torn to pieces, and new, health- 
 ful ones are formed. The patient is taught how to inhibit 
 wrong impulses and actions, and how to encourage right ones. 
 The advantage of hypnosis consists in increasing the sug- 
 gestibility of the patient. Most psychotherapists assume the 
 existence of an unconscious mental state, which they term the 
 subconscious mind, and beheve that it is through this medium 
 that suggestion acts. To the physiologist the phrase "sub- 
 conscious mind" is a contradiction in terms. He prefers 
 to regard mind and consciousness as synonymous, and so- 
 called subconscious phenomena, however complex they may 
 be, as neural phenomena, the ordinary physiological or 
 physico-chemical processes of nervous tissues, to which no 
 psychic qualities are added. 
 
 Psychotherapy, though it is "centuries old, and though 
 worthy endeavors are now being made in its behalf, is still 
 hardly out of its infancy, and its growth on a really scientific 
 or rational basis demands a much fuller knowledge than we 
 possess at present of the ways in which nervous tissue nor- 
 
METHODS OP TREATING DISEASE 63 
 
 mally works. Until such a physiological basis is secured, 
 psychotherapy will continue to attract the charlatan and the 
 credulous, the one to prey upon the other. That "mystery 
 will lead millions by the nose" has been abundantly demon- 
 strated in this field of mental healing. Hard-headed, mature 
 men, who are masters of material things, will here lay aside 
 their forceful intellects and think to find relief from physical 
 ills in the seductive conceptions of unknown psychic forces. 
 So-called healers are ever ready to take advantage of this 
 htmaan weakness. Even the presence of the body of the 
 patient is no longer demanded. It can go about its business, 
 and all unbeknown will still yield to absent treatment. In 
 the midst of human ignorance and credulity and all the 
 vagaries and deceptions of mind cure, scientific medicine has 
 before it a great task of education. 
 
IV 
 
 BACTERIA AND PROTOZOA AND THEIR RELATION TO DISEASE 
 
 From time immemorial human life has been cursed by the 
 two great evils of war and pestilence. Working at times 
 together, at times apart, there is no portion of the earth and 
 no race of men that they have not devastated. The one has 
 slain its thousands, the other its millions, and sorrow and 
 misery have ever accompanied and followed them. Ages 
 have come and gone, while through them all the clash of arms 
 has sounded and murderous plagues have silently spread 
 unchecked. Now in the morning of the twentieth century 
 the moral nature of man has risen against the one of these 
 evils, and all his science is invoked against the other; and 
 there is ground for the great hope that when our century 
 passes away, they also will pass, and man will be freed for- 
 ever from two of his greatest burdens. 
 
 The scientific features of modern medicine are nowhere 
 more graphically illustrated than in the conquest of the 
 infectious diseases. Scarcely a half century has elapsed 
 since the nature of these diseases first became known; for 
 it was during our Civil War that Louis Pasteur's labors were 
 rapidly approaching their goal, and it was in 1876 that Robert 
 Koch, in a study of anthrax, or splenic fever, conclusively 
 demonstrated for the first time that a specific bacterium is 
 the causative agent of a specific human disease. During 
 this half century a whole new science, that of bacteriology, 
 
 64 
 
BACTERIA AND PROTOZOA 65 
 
 has come into being, and mankind has for the first time learned 
 to know the real meaning of sanitation. 
 
 The term "infectious disease" is applied to all those forms 
 of disease which result from the invasion of the body by 
 microscopic organisms. The micro-organisms, or germs, of 
 most of the infectious diseases belong to the remarkable group 
 of primitive creatures called bacteria. The authority of that 
 ancient and unknown Hebrew, who once proclaimed that 
 there is no thing new under the sun, received a rude shock 
 toward the close of the seventeenth century, when Anton 
 van Leeuwenhoek of Delft, by means of his newly invented 
 glass lenses, showed to his fellow countrymen an unsuspected 
 world of animalculae in the midst of reputed Dutch cleanli- 
 ness. The Jesuit priest, Kircher, is said to have been the first 
 man to see bacteria, in 1659; but their importance in natural 
 processes was not shown until one hundred and fifty years 
 later, when Pasteur performed his immortal work. The 
 successive steps of Pasteur's achievement are now well 
 known — fermentation, spontaneous generation, the diseases 
 of wines, the diseases of silkworms, the diseases of higher ani- 
 mals, and lastly hydrophobia. I trust that I will be pardoned 
 if I here relate for the second time a personal experience con- 
 cerning Pasteur. 
 
 In the summer of 1886 it was my good fortune to spend a few 
 hours in the presence of this man in the rooms of the then 
 newly organized Pasteur Institute in Paris. It was in the 
 early days of the practical application of the results of his 
 long-continued, devoted experimentation regarding the cause 
 and treatment of hydrophobia. In a large room there was 
 gathered together a motley company of perhaps two hundred 
 persons, most of whom had been bitten by rabid animals. 
 Men, women, and children, from the aged to babes in the arms 
 
66 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 of their mothers, richly dressed and poorly dressed, gentle 
 folk and rude folk, the burgher and the peasant ; from the 
 boulevards and the slums of Paris, from the north, south, east, 
 and west of France, from across the channel in England, from 
 the forests and steppes of Russia, where rabid wolves menace, 
 from more distant lands and even from across the seas — 
 all had rushed impetuously from the scene of their wounding 
 to this one laboratory to obtain reUef before it was too late. 
 All was done systematically and in order. The patients had 
 previously been examined and classified, and each class passed 
 for treatment into a small room at the side : first, the new- 
 comers, whose treatment was just beginning ; then, in regular 
 order, those who were in successive stages of the cure ; and, 
 lastly, the healed, who were about to be happily discharged. 
 The inoculations were performed by assistants. But Pasteur 
 himself was carefully overseeing all things, now assuring him- 
 self that the solutions and the procedure were correct, now 
 advising this patient, now encouraging that one, ever 
 watchful and alert and sympathetic, with that earnest face 
 of his keenly aUve to the anxieties and sufferings of his 
 patients, and especially pained by the tears of the little chil- 
 dren, which he tried to check by filling their hands from a 
 generous jar of bonbons. It was an inspiring and instructive 
 scene, and I do not doubt that to Pasteur, with his impres- 
 sionable nature, it was an abundant reward for years of hard 
 labor, spent partly in his laboratory with test-tubes and mi- 
 croscopes, and partly in the halls of learned societies, com- 
 bating the doubts of unbelievers and scoffers, and compel- 
 ling the medical world to give up its unscientific traditions and 
 accept what he knew to be the truth. 
 
 Bacteria are regarded as rather more plant-like than ani- 
 mal-like in nature, although at such a low stage of existence 
 
BACTERIA AND PROTOZOA 67 
 
 no very sharp line of distinction can be drawn between plants 
 and animals. A' body of a bacterium consists of a single cell 
 possessing a very simple constitution — a bit of protoplasm, 
 probably some chromatin representing a nucleus, perhaps a 
 cell wall and capsule, and occasionally swimming organs in the 
 form of delicate projecting filaments. The bodies of most 
 bacteria have the form of a sphere, a straight rod, or a spiral 
 rod, and we therefore recognize the three groups of the coccus, 
 the bacillus, and the spirillum. There is much difference in 
 size among even individuals of a single species. One of the 
 smallest known species is the bacillus of influenza or grippe, 
 which is about 50000 of an inch in length ; one of the largest 
 is the spirillum of relapsing fever, which may reach a length of 
 even -j-J^ of an inch. The bacillus of typhoid fever varies 
 in length from ;sooo oi an inch to three times that figure. 
 Probably species exist which are too small to be recognized 
 even by the aid of our most efficient microscopes. When 
 surrounded by abundant food the life of a single bacterium 
 is very short. It is born by the division of its parent's body ; 
 for a brief period it tarries in its world to take food, grow, and 
 perform its good or evil work ; and then its body is split into 
 the bodies of its two offspring — and that is all the life and 
 immortality it knows. The duration of the life of a single 
 cholera germ under favorable conditions has been estimated 
 at twenty minutes, and its possible descendants in one day at 
 1600 trillions. If the lot of the bacterium is not cast in pleas- 
 ant places, and it faces a precarious existence, it may concen- 
 trate its substance, develop a resistant coat, and become an 
 inactive and hardy spore. In this state it rests until its en- 
 vironment becomes again favorable for growth. Bacteria 
 have the reputation of being very hardy creatures, but this 
 is only partly justified by fact. Most species can survive 
 
68 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 a brief exposure to extreme cold, some species even so extreme 
 a temperature as 300° F. below zero, and though prolonged 
 cold may kill them, ice not infrequently contains living germs. 
 Heat is more quickly fatal, and boiling water is sufficient to 
 kill all microbes that are likely to be present in it. When in 
 liquids, ten minutes' exposure to heat is fatal to typhoid 
 bacilli at 133° F. Bacterial spores are much more resistant 
 to heat, though it is gratifying to know that the formation 
 of spores is not very common with those species that are 
 responsible for diseases. Sunlight is very destructive to 
 bacteria, but, unfortunately, they can readily penetrate to 
 places to which the sun's rays can never hope to follow. 
 Thorough drying is also destructive, and renders innocuous 
 most germs within a few hours or a few days, although here 
 also spores are more resistant. Many chemical substances 
 are poisonous to bacteria; and valuable among these as disin- 
 fectants or germicides are formaldehyde, carbolic acid, bi- 
 chloride of mercury, and sulphate of copper. 
 
 Between one thousand and fifteen hundred species of 
 bacteria altogether have been described. It is probable that 
 these species are constant and that one does not pass into 
 another. Moreover, there is no evidence that new species 
 are now arising. Bacteria may be distinguished from one 
 another partly by their microscopic appearance, though thus 
 only in a limited degree, but chiefly by other characters, such 
 as the kind of food required by them, their manner of growth, 
 their chemical reactions, their products, their relation to the 
 factors of their environment, their behavior toward staining 
 reagents, and other general biological activities. We ought 
 to be very sparing of a general condemnation of bacteria. 
 Most of the known species live outside of animal organisms, 
 and many of these are of great importance to the welfare and 
 
BACTERIA AND PROTOZOA 69 
 
 pleasure of mankind. Of such as are beneficent to man I 
 might mention those which perform many of the helpful 
 fermentations and putrefactions of organic matter; those 
 which replenish worn-out soils by abstracting nitrogen from 
 the atmosphere and offering it in a form available for the 
 growth of plants ; those which ripen cream and thus transmit 
 to butter its pleasant flavor ; those which are engaged in the 
 making of cheese ; and those which tan hides and thus make 
 leather possible. Certain souls may question the beneficence 
 of certain other species which contribute to the pleasure of 
 man. Among these I may mention those that aid in the 
 curing of tobacco and those that contribute to the fermenta- 
 tion of wines. A certain number of bacteria have, in the 
 course of time, come to be parasitic upon animals and men. 
 Some of these are harmless, some are probably beneficial, 
 and a few are the producers of disease. We know nothing 
 of the way in which bacteria came to reside in the human body. 
 Medicine has no Milton to tell of this in stately verse. But 
 if the fall of man really "Brought death into the world and 
 all our woe, " perhaps the fatal apple was the bearer of man's 
 first disease germs. 
 
 The paths by which bacteria enter the body are compara- 
 tively few. A healthy uninjured skin forms a coat of armor 
 that is practically impenetrable by them, except when they 
 are brought by intermediate hosts, such as biting insects. 
 But our bodies must have inlets and outlets, and these, 
 together with skin wounds, are the danger points. If we 
 breathe — and we must breathe — floating germs may come 
 to our air passages and lungs. If we eat or drink — and we 
 must eat and drink — germs may enter our mouths and may 
 pass on to our stomachs and intestines. Doubtless the danger 
 of infection from breathing is popularly exaggerated, and in 
 
70 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 general is not so great as the danger from whatever is placed 
 in the mouth. Bacteria are very light and can float in air 
 for a considerable time, but though the air is one considerable 
 source of tuberculosis and probably of influenza, most float- 
 ing bacteria are probably either dead or not pathogenic. 
 To the mouth go water, milk, uncooked food, unclean dishes, 
 hands, and other objects, all of which may be the carriers of 
 pathogenic germs. 
 
 While the entrance of bacteria into the body should, if 
 possible, be prevented, it is gratifying to know that the 
 presence there, even of pathogenic species, does not ensure 
 diseases. Doubtless all of us at this moment are carrying, 
 each within his own person, the living germs of pneumonia 
 and various minor aihnents, while some of us probably pos- 
 sess the bacilh of tuberculosis, influenza, and perhaps diph- 
 theria. But this, however, need give us no alarm. One 
 swallow cannot make a summer, nor can one germ make a 
 disease, except in the rarest of cases. Usually many of the 
 same kind are required. Moreover, the individual bacteria 
 of a species vary in virulence, a property that is not well un- 
 derstood; and a certain degree of virulence is required if the 
 disease is to appear. There are many close analogies in be- 
 havior betweien the seeds of a higher plant sown in the 
 ground, and the germs of a disease planted in the hmnan 
 body. The sower who went forth to sow found that, what 
 with the fowls of the air, the stones of the earth, the heat of 
 the sun, and the thorns, only that seed which fell on good 
 ground brought forth fruit. So bacteria, after entering a 
 body, find many trials awaiting them: the body may possess 
 an immunity against them ; there is no soil in which they can 
 thrive ; and they have enemies to overcome. Some of these 
 difficulties are now understood, while some are still mysterious. 
 
BACTERIA AND PROTOZOA 71 
 
 In the preceding lecture I spoke of some of the natural 
 defenses of the body against disease.^ I wish now to amplify 
 this subject with reference to bacteria. If the latter enter 
 the air passages of the nose, pharynx, trachea, or lungs, they 
 are very liable to become caught in the mucus that is secreted 
 by the cells in the walls of these passages, and to be swept 
 outward again by the innumerable ciUa which are restlessly 
 sweeping the surfaces. Some of them may, however, find 
 lodgment on the mucous membranes. Many of those which 
 reach the stomach are killed by its acid and are digested by 
 the gastric juice. Some, however, such as cholera and ty- 
 phoid germs, if they succeed in passing the stomach, find a 
 more congenial environment in the intestine. If in the mu- 
 coiis membranes of the air passages and the alimentary canal 
 there chance to be places where, because either of mechanical 
 injury or nutritional disturbance, the tissues do not possess 
 their usual degree of healthy resisting power, the bacteria 
 may find the breaches in the walls and push their way in, 
 just as they may also enter through wounds in the skin. 
 Once within the tissues, some varieties, like the germs of diph- 
 theria and tetanus, found colonies at their place of entrance ; 
 others are carried by the blood to more satisfactory local 
 regions ; while still others do not remain in one locality, but 
 continue to share the rushing, changing Ufe of the constantly 
 moving blood. Wherever they chance to abide, if they find 
 food, an agreeable temperature, and other satisfactory condi- 
 tions of life, they proceed to grow and multiply. Then 
 begins a struggle for supremacy between the established and 
 organized tissues of the body and the unorganized horde of 
 invaders. To learn the intricate details of this struggle has 
 required the labors of an army of investigators, many of 
 
 ' See p. 42. 
 
72 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 them leaders in scientific medicine. Fact has led to hypothe- 
 sis, hypothesis to further fact ; theories have been proposed 
 and discarded ; and gradually, out of the complex maze, there 
 has arisen a great body of truth. Though the labor is in- 
 complete as yet, and its end is probably still far away, it is 
 interesting, both as an example of remarkable scientific 
 achievement and as affording a basis not only for an imme- 
 diate saving of many lives, but also for an ultimately complete 
 conquest of the infectious diseases. 
 
 Bacteria sometimes interfere with bodily processes in a 
 merely mechanical way, as any other foreign matter in large 
 quantity within the tissues might interfere. But they are 
 chiefly harmful through peculiar chemical substances which 
 they produce. These substances are poisonous or toxic to 
 living substance, and are hence called toxins. Some of them 
 are powerful poisons: the toxin of tetanus is said to be 
 about two hundred times more poisonous than strychnine. 
 The toxins appear to be of two kinds. One kind, the exo- 
 toxins, are freely given out during the life of the bacterial 
 cell ; the other, the endotoxins, are locked tightly within the 
 cell and are only released at its death and dissolution. The 
 relative quantities of these two vary with the varieties of 
 bacteria : the poisonous properties of the germs of diphtheria 
 and tetanus are due preeminently to their exotoxins; those 
 of cholera, typhoid fever, and pneumonia to their endo- 
 toxins. Once the toxins are set free, they are carried by the 
 blood to all parts of the body, and they may be absorbed by 
 the body cells and exert their poisonous action. They con- 
 stitute the more immediate cause of the disease. An infec- 
 tious disease, therefore, is substantially a poisoning of the body 
 by a powerful chemical substance. The common symptoms 
 of such a disease are fever, chills, a rapid pulse, headache. 
 
BACTERIA AND PROTOZOA 73 
 
 delirium, muscular weakness, general prostration, and often 
 characteristic rashes or eruptions in the skin. A certain 
 period must always elapse between the advent of the bacteria 
 and the appearance of the symptoms in sufficient force to 
 indicate the presence of the disease. During this period of 
 incubation the bacteria are growing and multiplying and 
 producing their toxins. The period of incubation of most 
 infectious diseases is less than one week, of typhoid fever 
 usually from eight to fourteen days. When unopposed and 
 not terminating fatally, the disease usually runs a definite 
 course, becoming at first for a time more and more severe, 
 then reaching its culmination, and finally slowly abating. 
 
 But the body does not passively submit to the ravages of 
 its unwelcome invaders. It has many means of defense, 
 and these are automatically put into action as soon as the 
 enemy appears. The two obviously direct ways of dealing 
 with the situation would appear to be, first, to prevent ex- 
 isting toxins from exerting their deleterious action, and, 
 secondly, to destroy the bacteria and thus prevent the for- 
 mation of more toxins. The body, of its own accord, makes 
 use of both of these methods. It opposes at least the exo- 
 toxins with antitoxins, and it opposes bacteria with anti- 
 bacterial agencies and leucocytes. It is worth our while to 
 consider these methods of defense more fully. 
 
 It has been found that whenever foreign matter, such as 
 living or dead organisms or the products of organisms, is 
 introduced into the tissues of an animal, the animal's cells 
 are stimulated to produce chemical substances which are in 
 certain ways antagonistic to the foreign matter, and tend to 
 protect the animal's body from it. To these protective 
 substances the general name antibodies has been given. 
 Many varieties of antibodies have already been recognized, 
 
74 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 and undoubtedly others exist, as yet unknown. Antitoxins 
 constitute one group of antibodies. When a specific toxin 
 attacks the living cells of an individual body, the cells may 
 ultimately succumb, but this may not occur until they have 
 made efforts to resist the attack. They are stimulated by 
 the toxin to manufacture a specific substance, the antitoxin, 
 which has an affinity for the corresponding toxin and the 
 power of neutralizing its poison. They manufacture this in 
 considerable quantities, much more than is required for neu- 
 tralizing the small amount of toxin that attacks the cells in 
 question, and the excess is generously poured out of the cell, 
 circulates through the body with the lymph or blood, and 
 may unite with whatever free toxin it chances to meet. This 
 marriage of toxin and antitoxin renders the toxin harmless, 
 and thus other cells are protected. 
 
 While some of the body cells are thus busy in the forma- 
 tion of antitoxin, either the same cells or others engage in an- 
 other kind of protective labor by the production of antibodies 
 which are destructive to the bacteria. These have been 
 called antibacterial, bactericidal, or bacteriolytic substances, 
 or, in brief, bacteriolysins. There are different theories 
 regarding the process by which bacteria are destroyed, but 
 thereHs general agreement in the fact that two antibodies are 
 engaged in it. One of these is the actual destructive agent, 
 but it can act only with the cooperation of the other. If we 
 accept a very helpful conception of Ehrlich, we must believe 
 that there is normally present within the blood a quantity of 
 the destructive agent, which he calls complement, while the 
 cooperative agent, which he calls immune body or ambo- 
 ceptor, is produced by the body cells when stimulated by 
 the bacteria. The amboceptor acts as a middleman between 
 the complement and the bacterium, bringing about the 
 
BACTERIA AND PROTOZOA 75 
 
 chemical union of the two. This union is fatal to the bac- 
 terial cell, for after taking its complement it becomes quiet 
 and its substance breaks up into granules and gradually dis- 
 solves — and thus the unwelcome guest is disposed of. 
 
 With some diseases, however, there is a certain degree of 
 danger to the body involved in a wholesale destruction of the 
 bacteria contained within it. These are the diseases of which 
 the bacterial poisons are endotoxins. These toxins differ from 
 other bacterial toxins in that they are locked within the liv- 
 ing substance of the bacterial cells, and are freed only on the 
 death of the latter. The relations of endotoxins are not yet 
 altogether elucidated. The body cells do not seem to be 
 capable of manufacturing antitoxins for them, and we do not 
 know definitely how the body defends itself against them, but 
 it seems that if a large quantity of them are rapidly set free, 
 they may poison the tissues and cause death. They afford 
 a further instance of the varied agencies by which bacteria 
 may overcome the body. 
 
 Investigators have discovered many other antibodies 
 besides antitoxins and antibacterial substances, which are 
 capable of exerting still other actions ; but their significance 
 in the subject under discussion, namely, the mutual relations 
 of bacteria and the body, is not yet altogether clear. One 
 fact of great interest, however, is that antibodies are among 
 the most highly specialized substances of which we have 
 knowledge. Each is adapted to the special work for which 
 it was created, and to no other. The antitoxin of diphtheria 
 cannot neutralize the toxin of tuberculosis. The antibac- 
 terial substance that is destructive to diphtheria germs is 
 ineffective with the germs of tuberculosis or typhoid or 
 erysipelas or pneumonia. As Ehrlich has expressed it: 
 "Antitoxins and antibacterial substances are, so to speak, 
 
76 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 charmed bullets, which strike only those objects for whose 
 destruction they have been produced by the organism." 
 Hence if two varieties of bacteria happen to attack the body 
 at the same time, each comes into conflict with the weapons 
 best adapted to cope with its own pecuUar means of warfare. 
 The ingenuity of the body in meeting the exact conditions 
 presented to it seems to be almost without limit. 
 
 Ehrlich, who has been one of the most stimulating and sug- 
 gestive investigators of the antibodies, has proposed a very 
 helpful scheme for interpreting the mutual relations of bac- 
 teria and the body cells, and has pictured it in graphic form. 
 Both his conception and his figures have been very helpful in 
 enabling us to uaderstand what are, in reality, very complex 
 processes. He behaves these relations to be analogous to 
 those that hold between food and the body cells. From the 
 standpoint of nutrition, he considers it possible to classify 
 the chemical substances of which the cell is composed into 
 two main groups of substances, distinguished by the respective 
 duties which they have to perform. There is the main mass 
 of cell substance which carries on the special activities 
 that characterize the cell ; and then there are special clusters 
 of atoms whose duty it is to bring this main mass into rela- 
 tions with the varied substances in the environment. These 
 clusters of atoms, which may be very numerous, may be ap- 
 propriately called receptors, and it is only through its recep- 
 tors that the cell is able to take food and other matter. Each 
 receptor is adapted to receive only its appropriate material 
 — one receptor one kind of food or other matter, another re- 
 ceptor another kind. Some receptors are adapted to receive 
 the toxins of particular species of bacteria ; others are adapted 
 to the bacteria themselves. If a toxin happens along and 
 meets its appropriate receptor, a chemical union between the 
 
BACTERIA AND PROTOZOA 77 
 
 two takes place. The toxin may kill the cell, or it may 
 stimulate the cell to produce and set free other similar re- 
 ceptors. These free receptors constitute the antitoxin. Or 
 a bacterium may happen along and find its appropriate re- 
 ceptor, and again a union takes place ; again the cell is stimu- 
 lated; and its amboceptors are set free. 
 
 But the story of the struggle between bacteria and the body 
 is not yet complete. In some way not fully understood the 
 presence of bacteria arouses to action certain varieties of the 
 white corpuscles of the blood. Isolated bacteria may be 
 attacked by isolated leucocytes; and a localized crowd of 
 bacteria may become the center of a crowd of leucocytes. 
 The latter proceed to fall upon the invaders and devour 
 and digest them. This process is known as phagocytosis, 
 and for the time the hungry leucocytes are phagocytes. 
 Metchnikoff was the first man to make known the phag- 
 ocytic activities of the white blood corpuscles, and has 
 constantly insisted upon their great importance in combat- 
 ing bacterial diseases.' Quite recently Sir Almroth Wright, 
 of London, and others have extended our knowledge. It had 
 been known for some time that the extent to which phago- 
 cytosis occurs in a given body differs greatly at different times. 
 Sometimes the leucocytes will take in no bacteria at all, 
 or only a few ; sometimes they will take in many ; sometimes 
 they will cram themselves so full as almost to burst. It was 
 suspected that these differences in behavior were due to some 
 unknown substance in the blood, and it was thought at first 
 that this substance stimulated the leucocytes and made them 
 eager for bacterial food. But later it was concluded from 
 experiments on rabbits that the substance must act on the 
 bacteria themselves, rather than the leucocytes ; and about 
 
 ' See also p. 45. 
 
78 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 six years ago this became clear. The unknown substance 
 has now been shown to constitute a class of antibodies, to 
 which the name opsonins has been given, from the Greek 
 word meaning "to prepare food for." Opsonins exist more 
 or less abundantly in the blood and among the tissues. They 
 are absorbed by the bacteria and affect them in such a man- 
 ner as to render them palatable to the leucocytes, who are 
 irresistibly drawn toward the bacteria and surround, engulf, 
 kill, and digest them. Opsonins are just now receiving much 
 attention from scientific investigators. Their origin is not 
 yet clear — they are probably manufactured and given off 
 to the blood plasma by the leucocytes. Their relation to 
 other antibodies is not altogether understood — it has been 
 suggested that they are identical with some of the antibacte- 
 rial substances. They seem to be always present in the body, 
 though their quantity varies greatly. There seem to be. 
 many varieties of them, and each variety is adapted to one 
 kind of bacterium : typhoid opsonins are taken up by typhoid 
 bacilli; pneumonia opsonins by pneumococci. The degree 
 to which the germs of any disease are destroyed by leucocytes 
 depends on the quantity of the specific opsonin that is pres- 
 ent. If there is an abundance of it, phagocytosis becomes 
 a most valuable aid in ridding the body of bacteria. 
 
 Thus the body's methods of defense against its hostile 
 immigrants are three in number. It neutralizes the bacterial 
 toxins by antitoxins; it destroys bacteria by antibacterial 
 substances ; and it also destroys bacteria by its phagocytes 
 with the aid of opsonins. It does not appear, however, to 
 employ all of these methods to an equal degree with any one 
 disease. Thus in diphtheria both antitoxin and phagocytes 
 are important, but the destruction of the germs by antibac- 
 terial substances seems to be very doubtful. In cholera the 
 
BACTERIA AND PROTOZOA 79 
 
 antibacterial method is perhaps the sole one employed. In 
 typhoid and pneumonia phagocytosis is probably the chief 
 method, while in dysentery and the plague antibacterial sub- 
 stances seem to play the principal r61e. We do not know how 
 there happen to be these differences, and there is still much 
 divergence of opinion concerning the actual mode of de- 
 fense in different cases. Of the three methods it seems at 
 present probable that the most nearly universal one is phag- 
 ocytosis. The simple, little, wandering, primitive, white 
 blood cells appear to be our chief protectors against bacterial 
 enemies. They are our soldiers, our national guardsmen, our 
 policemen all together; and, if the world ever chooses to be- 
 stow honor upon any single part, instead of the whole of a 
 man, its chiefest homage ought to be paid to these lowliest of 
 cells. 
 
 Bacteria are not the only variety of microscopic beings that 
 bring disease to man. From what we know of them it is not 
 surprising to learn that other forms of low organisms have ac- 
 quired a similar parasitic habit of Hving, and that man is made 
 to suffer from these also. These other organisms to which 
 I refer belong to the lowest order of animal life, the protozoa. 
 Although their bodies consist of but a single cell, protozoa 
 both structurally and functionally, stand higher in the bio- 
 logical scale of organisms than do bacteria. Their protoplasm 
 often includes more or less elaborate structures, such as 
 mineral substance serving as a skeleton, primitive muscle, 
 cilia for locomotion and the capture of food, a mouth and a 
 primitive cesophagus, contractile vacuoles, which serve as 
 primitive excretory organs, and a double nucleus. Various 
 physiological functions are often highly developed in them, 
 examples of which are the power to respond to stimuli, the 
 coordination of different parts of their cell, and various meta- 
 
80 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 bolie activities. They reproduce by both asexual and sexual 
 processes. The group of the protozoa is a very large one, 
 and, although the number of species that are parasitic in 
 man's body is considerable, those that have been conclusively 
 recognized as the causative agents in human diseases are 
 scarcely more than four or five. These diseases comprise ma- 
 laria, the sleeping sickness of Africa, and the tropical fevers 
 which have been variously named, such as dumdum fever, 
 and kala azar. In these cases the germs have a somewhat 
 elaborate life history, with two stages, which ai:e passed re- 
 spectively in the bodies of human beings and certain species 
 of insects. Human beings receive the germs through the 
 bites of infected insects, and thus infected, they may also 
 transmit the germs if they are bitten by other insects. The 
 Hfe history of the malarial organism is best known, having 
 been very fully worked out about ten years ago. At least 
 three species, if not four, of simple protozoa have been recog- 
 nized as the germs of the various types of malarial disease. 
 Within the infected human body they live in the red corpuscles 
 of the blood. They multiply asexually, and destroy the cor- 
 puscles. While man is thus one of their hosts, the mosquito 
 of the genus Anopheles is the other. Why nature should 
 have ordained that only the female mosquito shall suck 
 the blood of its victim, and hence be the sole carrier of the 
 germs, is not clear. Yet such is the fact. Within the stom- 
 ach of the insect the germs thrive and multiply sexually, and 
 ultimately they swarm through the body and reach the 
 salivary gland. Here they await their transmission to the 
 body of the next human victim, and thus the cycle is con- 
 tinued. 
 
 The relation of the protozoan Trypanosoma to the deadly 
 African sleeping sickness has been demonstrated within ten 
 
BACTERIA AND PROTOZOA 81 
 
 years. The organism is a long cell, twisted somewhat spi- 
 rally, and is continually moving by means of a delicate undu- 
 lating membrane attached along one edge and extended at 
 the « posterior end into a freely whipping flagellum. It is 
 transmitted to its human victim by the bite of the tse-tse 
 fly, Glosdna palpalis. It lives at first within the blood, and 
 later appears in the cerebro-spinal fluid. It multiplies ac- 
 tively, and produces fever, emaciation, somnolence, and ulti- 
 mately coma and death. Its full fife history is not known. 
 
 Almost nothing is known regarding the chemical or meta- 
 bolic activities of the pathogenic protozoa and the reactions 
 to them on the part of their hosts. Protozoan diseases, 
 however, resemble in many ways bacterial diseases, and it is 
 probable that the germs of the former also produce toxins 
 and are opposed by antibodies, but here is an opportunity 
 for research. 
 
 The infectious diseases, indeed, still offer abundant oppor- 
 timities for investigation. For a considerable number of 
 them there is yet no certainty as to the identity of the or- 
 ganism that causes them. There is a certain amount of 
 evidence that protozoa are responsible for rabies, smallpox, 
 scarlet fever, trachoma, and a form of dysentery called 
 amebic dysentery. Thus, minute particles which suggest 
 protozoan forms are found in the brain cells of victims of 
 rabies, and in the skin cells of those of smallpox. But in 
 all of these cases conclusive evidence as to the nature of the 
 causative organisms is wanting. Mumps, measles, typhus 
 fever, infantile paralysis, yellow fever, and some other un- 
 doubted infections still defy all search for the germina,! 
 agent. In the case of infantile paralysis and of yellow fever 
 the virus retains its infectious property, even after being 
 filtered through a fine porcelain filter. It is therefore sus- 
 
82 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 pected that the germs are too minute to be recognized with 
 the present powers of our microscopes. 
 
 We who hve our hves in civihzed communities are subject 
 to a malady, in itself not serious, which is the cause of great 
 personal annoyance, is often the forerunner of dangerous 
 disease, and contributes in many ways to man's misery. I 
 refer to our common enemy, "colds." A "cold" is charac- 
 terized by a congestion and swelling of the tissues forming 
 the walls of the air passages of the nose and throat, a mucous 
 secretion from the walls which is at first watery and irritat- 
 ing and later becomes thicker, soreness of the throat and 
 pain in swallowing, hoarseness, sneezing and coughing, an 
 abundant secretion of tears, headache, sUght fever, a rapid 
 pulse, a dry skin, an impairment of the senses of smell, taste, 
 and hearing, and sometimes bronchial irritation. There may 
 be an accumulation of pus in the middle ear and in the cavi- 
 ties of the frontal and cheek bones. The term "cold" is em- 
 ployed loosely and is a misnomer, since the malady does not 
 necessarily have any relation to external cold. Different 
 technical names are given to it in accordance with the local- 
 ity in which the symptoms are most pronovmced, and thus a 
 "cold" may be a rhinitis, a pharyngitis, a laryngitis, or even 
 a bronchitis. It is now generally acknowledged that, what- 
 ever its locality, it is caused by bacteria and is contagious. 
 Various attempts have been made to discover its causative 
 germ, and there are differences of opinion as to the latter's 
 identity. Two organisms, called Bacillus coryzm segmentosus 
 and Micrococcus catarrhalis, have been found to be commonly 
 and abundantly present in the air passages during acute at- 
 tacks of "cold," and are believed by some investigators to be 
 chiefly responsible for the common symptoms. Other bac- 
 teria, such as the paeumococcus, the pneumobacillus, the 
 
BACTERIA AND PROTOZOA 83 
 
 streptococcus, the staphylococcus, and the bacillus of influ- 
 enza, are not infrequent. According to our present knowl- 
 edge, therefore, a " cold " appears to be not a specific disease 
 caused by a single species of organism, but rather an infec- 
 tion resulting from the activities of several species, some of 
 which, at least, live constantly upon the surfaces of the air 
 passages. We have little exact knowledge of the bodily 
 conditions under which these organisms, some of which are 
 harmless ordinarily, suddenly begin to thrive, multiply, and 
 perform their offensive work. Exposure of the body to ex- 
 ternal cold and to drafts of air, which are popularly believed 
 to be the chief causes of colds, is probably less potent than 
 many other general conditions, such as fatigue, indigestion, 
 and the maltreatment of the body in many ways. 
 
 It might here prove interesting to consider some of the 
 specific media that have been demonstrated to convey disease 
 germs to the human body. It is known that the bacilli of 
 typhoid fever may be carried into the body in water, milk, 
 oysters, and other solid food, and by means of infected fingers 
 or articles of household use. Probably water and milk are 
 the chief carriers of typhoid germs. They may be trans- 
 mitted from the dejecta of human beings to these media in 
 various ways, but it seems undoubted that house flies are not 
 infrequent carriers of them. The germs of diphtheria have 
 been proved to be disseminated in milk, but probably the 
 most common media of their transmission are personal 
 articles, such as clothing, toys, and common drinking cups. 
 The germs of tetanus are received through wounds in the 
 skin when they have become contaminated with soil, dust 
 from various sources, particles from the explosive caps of toy 
 pistols, rusty nails, and other articles on which the tetanus 
 bacilli may survive. The germs of scarlet fever may be 
 
84 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 conveyed by infected milk and also by personal articles 
 which have been in contact with those afflicted by the dis- 
 ease. The germs of tuberculosis may likewise be acquired 
 by personal articles, by the breathing of germ-laden air, 
 through the medium of milk, at least in children, and prob- 
 ably occasionally by means of butter and cheese. The germs 
 of cholera are conveyed by water, milk, raw foods, such as 
 salads, which have been washed in infected water, and by 
 personal articles. House flies may carry them. Malaria and 
 yellow fever result only from organisms conveyed by the 
 bites of certain species of mosquitoes, which have become 
 infected from other human beings. The bacilli of the 
 plague are conveyed partly by human contact and personal 
 effects, and partly by the bites of fleas which have become 
 infected from rats and other animals. The germs of small- 
 pox are transmitted by personal contact, and probably by 
 the air. Hydrophobia results from organisms received from 
 the bites of rabid animals which have been bitten by other 
 rabid animals. 
 
 The more the dissemination of bacteria is studied, the 
 clearer it appears that the most nearly universal mode of 
 transmission of the more widely distributed infectious dis- 
 eases is through contact with an infected person and in- 
 fected personal articles. This view is supported by much 
 evidence, drawn from the careful tracing of the sources of 
 specific infections. It has also come to be recognized that 
 many of those who carry the living germs do not at the time 
 possess the disease, may never have possessed it in the past, 
 nor are they destined necessarily to possess it in the future. 
 Such persons have come to be known as bacteria carriers, 
 and, although they appear to be in good health, they may be 
 the unwitting transmitters of the disease to others. Bacteria 
 
BACTERIA AND PROTOZOA 85 
 
 carriers are undoubtedly active in the spread of diphtheria 
 and typhoid fever, and probably of pneumonia, influenza, 
 epidemic cerebro-spinal meningitis, infantile paralysis, and 
 many other diseases. The germs of diphtheria, pneumonia, 
 and influenza survive in the throat, those of epidemic men- 
 ingitis and infantile paralysis in the nose, and those of ty- 
 phoid fever in the gall bladder and the intestine. The case 
 of "typhoid Mary" has become historic in the annals of 
 New York medicine, the unfortunate woman whose trail as 
 a domestic servant was marked by the frequent appearance 
 of typhoid fever in the families of her employers. Twenty- 
 six cases of the disease were thus traced to her as the source of 
 infection. Several hundred cases were recently traced by Dr. 
 Park of the Department of Health of the City of New York 
 to the milk supplied from a farm employing a man who had 
 had typhoid forty-seven years before. Many localized out- 
 breaks of disease, which appear to be purely spontaneous 
 and have no causal connection with other cases, are probably 
 due to bacteria-carriers. It appears to be diflicult to destroy 
 the germs within the bodies of such individuals, who are 
 often a serious menace to society. This recent discovery 
 by scientific medicine thus presents a new sociological prob- 
 lem, the solution of which is not evident. 
 
« 
 
 THE TREATMENT AND THE PREVENTION OP INFECTIOUS 
 DISEASES 
 
 The time-honored treatment by the physician of a patient 
 suffering from a severe infectious disease has varied in detail 
 from time to time, but has consisted in general of an allevi- 
 ation of the various symptoms and a promotion of the indi- 
 vidual's general well-being. If pain were present, it could 
 be relieved by drugs. If there were fever, it could be dimin- 
 ished by drugs. If there were general prostration, rest and 
 food would tend to counteract it. But no one of these 
 measures touched the heart of the difficulty. Until very 
 recently drugs had proved of specific curative value in but 
 two instances : quinine in malaria and mercury in syphilis. 
 It is true that, if given in quantity, other drugs would kill 
 the germs, but such quantities as were required for this pur- 
 pose would kill the patient as well, and however effective 
 they might be with the disease, there were obvious objections 
 to a course of treatment that would thus terminate. With 
 the single exception of Jenner's discovery in 1796 of the 
 value of vaccination in smallpox, it was not until the year 
 1885, scarcely twenty-five years ago, that more specific meth- 
 ods began to be employed to aid mankind in his struggle 
 with infectious diseases. In that year Pasteur introduced 
 his method of combating rabies. This was the beginning of 
 a new era, and in the treatment and the prevention of the 
 infectious diseases modern medicine has demonstrated most 
 serviceable practical powers, and has won brilliant triumphs. 
 
 86 
 
TREATMENT OP INFECTIOUS DISEASES 87 
 
 Scarcely a year now passes without some valuable addition to 
 our resources in dealing with these greatest of mankind's 
 bodily scourges. The new methods are possible partly 
 because we have at last come to recognize the causative agents 
 of many of these diseases, partly because we have discovered 
 means of cultivating bacteria outside of living bodies, and 
 partly because we can produce the diseases in the bodies of 
 living animals and study their course and their treatment 
 under conditions which we can control. Without this 
 method of animal experimentation, indeed, our knowledge 
 would be mainly of scientific interest. 
 
 Bacteriologists have shown great ingenuity in devising 
 methods by which bacteria may be cultivated and studied. 
 Their laboratories have become veritable bacteriological 
 gardens, where living germs are kept under the very best 
 possible conditions. The species are separated from one 
 another ; the proper foods are given to each ; the most ad- 
 vantageous surroundings, as to light, temperature, air, and 
 moisture, are provided; the bacteria are nursed when ill; 
 and every effort is made that they may lead healthy Uves. 
 Opportunities are thus given for the exact study of their 
 activities. 
 
 When, a quarter of a century ago, this study had given 
 some notions of the life history of bacteria, it began to 
 dawn upon investigators that, if they could provide the un- 
 fortunate person attacked by the germs with an additional 
 supply of his own weapons, those substances which are an- 
 tagonistic to the bacteria or bacterial toxins and are specif- 
 ically fitted to meet their attacks, he would have greater 
 resources with which to fight the disease. Antibodies are 
 nature's own remedies, harmless to the patient, but fatal to 
 the germs and an antidote to their poisons. The argument 
 
88 SCIENTIFIC FEATUKBS OF MODERN MEDICINE 
 
 that because a thing is nature's own it must therefore be su- 
 perior to a similar object of man's device is an argument 
 that may easily be refuted by facts. Helmholtz is credited 
 with saying that if an instrument-maker should send to hinj! 
 an opticial apparatus as imperfect as the human eye, he would 
 return it. The common version of the tale is probably an ex- 
 aggeration. No one recognized more clearly than Helmholtz 
 the marvelous powers and adaptability of the human eye, 
 and yet, exact physicist as he was, he was acutely aware of 
 the imperfections of the human lenses, imperfections that 
 would not be tolerated in the optical instruments of the 
 present time. Man cannot make a human eye, but he can 
 make a lens that is largely free from chromatic and spherical 
 aberration and astigmatism. In the treatment of the infec- 
 tious diseases man has not yet discovered agencies that sur- 
 pass or even approach those that nature herself has devised, 
 unless the two or three examples of specific drugs be so con- 
 sidered, but he has been able to direct in certain ways 
 nature's methods of obtaining and employing these agencies. 
 When nature sets to work to prepare substances antagonistic 
 to bacteria or their products, she introduces her bacteria into 
 living bodies, and by them the body cells are stimulated to 
 manufacture and pour out into the blood the desired anti- 
 bodies. From man's standpoint it is a heroic method. It is 
 the old struggle for existence, which nature is always fond of, 
 and in which it is not foretold whether man or the microbe 
 shall prove to be the fitter to survive. Now scientific medi- 
 cine steps in, and tries to give man the advantage of its 
 knowledge. 
 
 Two methods are now employed in the treatment of these 
 diseases: one is to bbtain from some source, other than the 
 body of the patient, a quantity of the specific antibodies, and 
 
TREATMENT OF INFECTIOUS DISEASES 89 
 
 turn them over to him ; the other is to give to him specific 
 substances which can stimulate his own cells to be more active 
 in the production of antibodies. These methods are called 
 respectively the serum method and the vaccine method. 
 
 In the employment of the serum method a culture is made 
 of the species of bacterium that is the causative agent in the 
 disease. This should be a pure culture, free from contami- 
 nation with other species. Either some of these bacteria or 
 the toxins produced by them are injected into the body of a 
 suitable animal. The animal's cells are thereby stimulated 
 to produce antibodies, and cast them out into its blood. In 
 some cases these antibodies are antitoxins; in other cases 
 they are antibacterial substances, or opsonins. When the 
 animal's blood has acquired a considerable quantity of them, 
 it is drawn, and allowed to clot. From the more soUd por- 
 tion of the clot the serum or liquid part is then removed. It 
 contains, dissolved within it, the antibodies. Serum in itself 
 has no curative power ; it is simply a medium of holding the 
 antibodies, and is curative only in so far as it contains cura- 
 tive antibodies. When used it is injected into the patient's 
 body, and thus he is given a large stock of defensive agencies 
 at an earlier time than he is able to provide them unaided. 
 Specific serums are useful in dealing with diseased conditions 
 that have already made their appearance, but they may also 
 profitably be given to an individual in whose body the bac- 
 teria either have not yet appeared or have not got a consider- 
 able foothold, and thus an attack of the disease may be fore- 
 stalled. Their use as preventive agents, indeed, is often of 
 greater value than their curative use. Serums have now been 
 employed for a considerable number of infectious diseases. 
 Some of them have proved their eflBciency, and some have not. 
 
 Before considering them in further detail, I wish to say a 
 
90 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 few words regarding the significance and proper mode of 
 interpretation of medical statistics. The assertion that 
 statistics may be made to prove anything is as frequent as 
 the assurance that figures will not lie. The term " mortality," 
 as applied to diseases, has two meanings : it may signify either 
 the number of deaths in proportion to the population, or the 
 number of deaths in proportion to the number of persons 
 attacked by the disease. The former may be called the total 
 mortality, or death rate, the latter the case mortality. The 
 two do not necessarily vary pari passu. Thus, if an epidemic 
 occurs and more persons are attacked by the disease than 
 ^ before, more may die and the total mortality may be higher. 
 But if at the same time better methods of treatment are 
 used, the percentage of attacked persons who die may be 
 less than before, and thus, although total mortality may be 
 higher, case mortality may be lower. In determining whether 
 a certain method of treatment is efficacious or not within a 
 limited period of time or a limited locality, it is obvious that 
 the significant fact is the percentage of cures among those who 
 have received the ^treatment, or the case mortality. Um- 
 brellas will not prevent the rain from falling, but they may 
 diminish the number of persons who get wet. In the long 
 run, however, an eflScient remedy for an infectious disease 
 will gradually diminish the total death rate from the disease, 
 and will tend to eliminate it wholly from the earth's surface. 
 I speak of this matter of the significance of the term mortal- 
 ity, because it has happened that certain persons hostile to 
 the new therapy have misinterpreted the statistics, either 
 ignorantly or wilfully, and thus have attempted to justify 
 their prejudices. 
 
 Diphtheria antitoxin began to be used experimentally in 
 the year 1892, and within the subsequent three or four years 
 
TREATMENT OF INFECTIOUS DISEASES 91 
 
 it spread over the whole world. It is produced by injecting 
 into young, vigorous, healthy horses a powerful toxin obtained 
 from a virulent culture of the bacillus of diphtheria. Doses of 
 the toxin, at first small and then gradually increasing in quan- 
 tity, are injected hypodermically at intervals of from three 
 to seven days. Stimulated by this toxin, the horse's cells 
 produce antitoxin, and at intervals the antitoxic strength of 
 his blood is tested. Usually after two or three months it is 
 powerful enough for therapeutic use. Blood is then drawn 
 from the animal's jugular vein, with little inconvenience to 
 himself, at intervals of perhaps one week for several months, 
 regular injections of toxin still being continued. The anti- 
 toxic strength of the blood usually diminishes in the course of 
 time, and the animal is then allowed a period of freedom from 
 inoculation. Later it may be resumed, and a suitable horse 
 may thus periodically furnish strong serum for several years. 
 The blood after withdrawal is allowed to coagulate and the 
 serum loaded with antitoxin oozes from the clot, is drawn off 
 with strict aseptic precautions, and is placed in suitable 
 bottles. Sometimes a small quantity of an antiseptic is 
 added to it, although if kept in a cool dark place it remains 
 in good condition during many months without antiseptic 
 treatment ; in time it undergoes a slow deterioration. Dr. 
 Park and his staff of the Department of Health of the City 
 of New York have devised methods by which the antitoxin 
 may be freed from most of the other constituents of the 
 serum, and thus may be obtained in concentrated form. Its 
 amount in the serum may be determined by testing its pro- 
 tepting power on guinea pigs which have been inoculated 
 with a standard toxin. The unit of antitoxin is that amqunt 
 that will neutralize one hundred minimal fatal doses of such 
 a standard toxin. The antitoxin is always thus standardized 
 
92 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 at the laboratories before it is allowed to be used. When 
 employed with human beings it is injected either subcutane- 
 ously or directly into a vein, the latter being the more quickly 
 effective method of administration and advisable in serious 
 cases. For the prevention of diphtheria from 300 to 1000 
 units may be employed, and for treatment after the disease 
 has appeared, from 1500 to 20,000 units. 
 
 Deaths from Diphthebia and Cboup in the BoRotroHS of Man- 
 hattan AND THE Bronx, City of New York 
 
 Yeab 
 
 Number op 
 Deaths per 
 100,000 OP 
 
 POPtTLATION 
 
 Case Mor- 
 tality m 
 Percentage 
 
 1888 
 
 167.7 
 
 146.2 
 
 110.5 
 
 118.7 
 
 123.3 
 
 145.5 
 
 158.6 
 
 105.5 
 
 92.5 
 
 81.9 
 
 46.7 
 
 53.8 
 
 62.0 
 
 57.9 
 
 52.3 
 
 54.7 
 
 54.8 
 
 35.9 
 
 39.5 
 
 39.9 
 
 41.8 
 
 39.4 
 
 37.1 
 
 39.3 
 
 1889 
 
 35.3 
 
 1890 
 
 38.7 
 
 1891 
 
 36.7 
 
 1892 
 
 40.6 
 
 1893 
 
 36.2 
 
 1894 ... 
 
 29.7 
 
 1895 Antitoxin 
 
 1896 . . . 
 
 came into general use . 
 
 18.8 
 15.4 
 
 1897 
 
 14.6 
 
 1898 
 
 12.1 
 
 1899 
 
 13.2 
 
 1900 
 
 15 2 
 
 1901 
 
 15 9 
 
 1902 
 
 10 9 
 
 1903 
 
 10.6 
 
 1904 
 
 10 4 
 
 1905 
 
 10 
 
 1906 
 
 11 3 
 
 1907 
 
 11 6 
 
 1908 
 
 110 
 
 1909 
 
 11 5 
 
 1910 
 
 98 
 
 
 
TREATMENT OF INFECTIOUS DISEASES 93 
 
 In the city of New York antitoxin came into general use 
 early in 1895, when its free distribution to the poor by the 
 Department of Health began. Largely by its use the total 
 number of deaths from diphtheria and croup in every 100,000 
 of population in the Boroughs of Manhattan and the Bronx 
 has been reduced since 1894 from 158 to 37, and bids fair to 
 be still further lowered to 30 during the present year, while 
 the case mortality has decreased from 29.7 per cent to 9.8 
 per cent, or one third its former amount. The table on 
 the preceding page contains the official figures. 
 
 As with other serums, the beneficial action of the antitoxin 
 of diphtheria is greater the earlier in the course of the disease 
 it can be employed. This is very clearly shown by the 
 following records furnished by the Brook Hospital of England 
 for the eleven years from 1897 to 1907 inclusive : 
 
 Period op Disease when 
 Antitoxin was Administered Pbhobntage of Deaths 
 
 1st day 
 
 2d day 4.29 
 
 3d day H.24 
 
 4th day 16.89 
 
 5th day and subsequently 18.58 
 
 Besides its use as a curative agent, diphtheria antitoxin is 
 employed very widely as a preventive. For example, if one 
 child in a family is attacked with the disease, not only that 
 child, but the other members of the family should at once be 
 given antitoxin. If this be done, the spread of the disease 
 will be checked and the total mortality will be diminished. 
 The immunity conferred by a single injection usually lasts 
 at least two weeks, and by subsequent administration it may 
 be extended for a longer period. 
 
 The antitoxin of tetanus or lockjaw is prepared in essen- 
 
94 SCIENTIFIC FEATUEES OF MODERN MEDICINE 
 
 tially the same way as the antitoxin of diphtheria. Opinions 
 have differed as to the degree of its value in those cases in 
 which the disease has actually appeared, although it cannot 
 be denied that it possesses some curative power, especially 
 when injected into a vein. But there is no doubt of its 
 great efficacy as a preventive. Its administration is an 
 essential part of the treatment, in medical and surgical dis- 
 pensaries, of injuries which are incidental to our customarily 
 vigorous mode of celebrating the fourth of July, and many a 
 patriotic American youth owes his life to antitetanus serum. 
 During the past century there has occurred in the United 
 States and to some extent in foreign countries occasional 
 outbreaks of a dangerous infectious disease, known popularly 
 as spotted fever. It has destroyed many children, and left 
 others pitiable physical and mental wrecks. From its epi- 
 demic character and the fact that its primary symptom seems 
 to be an inflammation of the membranes or meninges cover- 
 ing the brain and spinal cord, it is called in medical circles 
 epidemic cerebro-spinal meningitis. It is now known to be 
 due to a specific bacterium, to which the name meningo- 
 coccus is given. This organism is present in abundance in 
 the nasal cavities of those ill with the disease. Its portal 
 of entry into the body is the nose, and through the nose also 
 it leaves the body, to infect, it may be, other unfortunate 
 persons. A severe epidemic of this disease has spread 
 over this country and a considerable part of Europe during 
 the past six years, and various investigators have been stimu- 
 lated to search for and to produce a specific serum for it. 
 The most successful effort has been that of Flexner of the 
 Rockefeller Institute in the city of New York. His serum is 
 prepared by the injection into horses of both living and dead 
 meningococci and an extract of them, which cause a reactive 
 
TREATMENT OF INFECTIOUS DISEASES 95 
 
 production of antibodies. These appear to be both antitoxin 
 and opsonin, the latter being especially developed. The 
 serum exerts also a destructive action directly on the living 
 bacteria. When employed therapeutically it is injected into 
 the spinal canal, and thus directly reaches the seat of the 
 disease. It has been used for nearly four years, and it is 
 estimated that it has reduced the mortality of the disease 
 approximately from 75 to 25 per cent. Its success has been so 
 pronounced that its preparation and distribution have now 
 been entrusted to the New York Board of Health, and it 
 takes its place beside the antitoxic sera of diphtheria and 
 tetanus as an accepted therapeutic agent. 
 
 Flexner in this country and other investigators in other 
 countries have now attacked another grievous infectious 
 disease of young children, namely, infantile paralysis. It has 
 been epidemic in this country for the past four years. It was 
 probably brought here from the Scandinavian countries in 
 1907. The foci of the epidemic seem to have been New York 
 and Boston, and from thence it has spread across the United 
 States. Its mortaUty is not high, rarely exceeding ten per 
 cent, but its baneful consequence is a partial paralysis of the 
 arms and legs, resulting from a destruction of certain of the 
 nerve-cells in the spinal cord. This paralysis is usually more 
 or less permanent, and thus severely handicaps the individual 
 in life's struggle. Here, as with other infectious diseases, 
 comparatively little advance had been made until the illumi- 
 nating method of animal experimentation began to be em- 
 ployed. Two years ago it was shown that the disease could 
 be transmitted to monkeys by inoculating them with an 
 emulsion made from the infected spinal cord of a child who had 
 died of the malady, and that thereby typical cases of it could 
 be produced. Thus the investigation began. The disease 
 
96 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 can now be readily transmitted by inoculation from monkey 
 to monkey. Its virus appears to contain a living organism, 
 and not simply a toxin. Its germ has not been identified, but 
 from the fact that it can pass through the fine pores of the 
 finest porcelain filter, it is inferred that it is one of the most 
 minute organisms. The virus is exceptionally resistant and 
 potent : even ywis^ of ^ single cubic centimeter of it, when 
 injected after filtration into the brain of a monkey, suffices 
 to produce paralysis. The disease is highly contagious, and, 
 as in epidemic meningitis, the germ enters and leaves the body 
 through the nose. It can be carried from place to place by 
 house flies. One attack often confers a long-continued, if 
 not a permanent immunity. This appears to be due to the 
 presence of antibodies in the blood. By the employment of a 
 suitable serum the onset of the paralysis can be delayed and 
 often wholly prevented in a certain proportion of infected 
 monkeys. Such a discovery hopefully points the way to the 
 possibility of obtaining an effective serum for use with human 
 beings, and active efforts are now being made toward this end. 
 
 A certain degree of success has attended the use of serums 
 with erysipelas, puerperal fever, scarlet fever, typhoid fever, 
 dysentery, and the plague, but none of these have yet come 
 into extensive use. Various attempts have been made to 
 produce serums for pneumonia, tuberculosis, and many other 
 infectious diseases. But while some investigators report 
 favorable results, these are not yet such as to warrant the 
 general use of this method. 
 
 In certain other pathological conditions success has attended 
 the use of specific serums. Here the principle of treatment is 
 the same as with the germ diseases, for the pathological agent is 
 a toxic substance which is capable of inducing the formation 
 of antibodies. Thus, while arsenic, strychnine, and morphine 
 
TREATMENT OP INFECTIOUS DISEASES 97 
 
 do not stimulate such production, on the other hand certain 
 vegetable poisons, such as abrin, ricin, and crotin, do so. 
 Moreover, a serum has been produced which seems to diminish 
 the virulence of hay fever. Considerable attention has been 
 given to the preparation of serums against the venom of poison- 
 ous snakes, which in India alone are responsible for the death 
 of 25,000 persons annually. A considerable degree of success 
 seems to follow the use of antivenene, prepared by the French 
 pathologist, Calmette. This appears to protect against the 
 evil effects of the bite of the cobra. India possesses a variety 
 of poisonous snakes, and a serum that is effective against the 
 venom of one is probably not efficient against another: 
 each serum seems to be strictly specific for its own poison. 
 If this is so, it would appear necessary for the bitten victim 
 to catch his snake and carefully determine its species before 
 knowing which serum he ought to use. The difficulties in the 
 way of this procedure are obvious. The hope has been ex- 
 pressed, however, that it will yet be possible to obtain a uni- 
 versal serum for snake bites. 
 
 While the serum method of treating infectious diseases has 
 thus already accomplished much in a few important diseases, 
 and will, without doubt, accomplish much more, its failures 
 in other diseases have turned many investigators to seek the 
 desired goal by means of vaccines. The principle involved 
 in vaccination consists in introducing into the body of the 
 patient not antibodies, as with serums, but rather specific 
 substances which are capable of stimulating the body cells 
 to activity in the production of antibodies. These specific 
 substances may be, as in smallpox and rabies, a weakened or 
 attenuated form of the same species of miqro-organism, or, 
 more usually, they consist of virulent germs, which, however, 
 have been killed before the injection. Once within the body 
 
98 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 they disintegrate, and the chemical substances thus released 
 act upon the body cells, causing the cells to produce and cast 
 out into the blood antibodies. In many cases, at least, 
 these antibodies are opsonins. The living germs absorb 
 them and become the palatable prey of the leucocytes. It is 
 not altogether clear why the dead organisms thus artificially 
 introduced are more efficacious than the living ones already 
 present, but such seems to be the case. 
 
 Investigators have been encouraged to turn to vaccination 
 by the great success that has attended the specific treatment 
 of smallpox. Smallpox is a very ancient disease, and until 
 recent years it has played a conspicuous r61e in history. For 
 many centuries it was one of the great unconquered enemies 
 of the human race. It was almost as inevitable as birth and 
 death. It spared neither high nor low. Wherever numbers 
 of people traveled they carried the disease with them : the 
 crusaders spread it over Europe ; Spanish seamen brought it 
 to America. In some manner, now unknown, in the cen- 
 turies before the beginning of the Christian era, inoculation 
 began to be practised in the Orient. This consisted in intro- 
 ducing under the skin of a healthy person some of the con- 
 tents of a pustule from a person having smallpox, and- thus 
 deUberately inducing the disease. Thus begun, it usually 
 ran a mild course, and conferred upon the patient a perma- 
 nent immunity. In the early part of the eighteenth century 
 the wife of the British ambassador to the Turkish Empire, 
 Lady Mary Wortley Montagu, during her stay in Constan- 
 tinople, became interested in Inoculation, and not only sub- 
 mitted her children to it, but caused its introduction into 
 England. Thepce it spread to America. Inoculation was a 
 courageous procedure, and, though effective, it was crude. 
 It occasionally was the means of conveying other diseases; 
 
TREATMENT OF INFECTIOUS DISEASES 99 
 
 with each case it provided a new center of infection; the 
 course of the disease in an individual was at times severe; 
 and occasionally it terminated in death. A historic case was 
 that of the eminent New England divine, Jonathan Edwards, 
 who submitted to inoculation and died within one month 
 after his inauguration as president of Princeton College. 
 At the time when our American colonies were struggling for 
 their independence, Edward Jenner, an EngHsh physician, 
 was endeavoring to devise a more satisfactory method of 
 combating this grievous disease. He is said to have learned 
 from a milkmaid that those persons who contracted the mild 
 cowpox were proof against the more severe smallpox. He 
 investigated for many years, and in 1796 performed his first 
 vaccination, using material from a human case of cowpox 
 which had been contracted in milking. His success excited 
 much interest, and his method soon came into widespread use. 
 The causative agent of smallpox has not yet been identified 
 beyond doubt, but it seems probable that it is a protozoan 
 rather than a bacterium. It is believed that cowpox and 
 smallpox are two different forms of the same disease, the 
 germ in the former being weakened by its bovine life. 
 
 Wherever vaccination has been practised thoroughly, there is 
 a nearly complete elimination of the disease. Thus in Sweden 
 in the twenty-eight years previous to vaccination, smallpox 
 killed 2050 persons annually out of every 1,000,000 of popu- 
 lation; and in each of the forty years following only 158 
 persons. Germany inaugurated in 1874, and still retains, a 
 model law, requiring all persons to be vaccinated in infancy 
 and again in the twelfth year; and in 1899, out of a total 
 population of 54,000,000 in the German Empire, there oc- 
 curred only 28 deaths from smallpox. Its presence at all in 
 Germany is due chiefly to its introduction by foreigners. Of 
 
100 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 the European countries Russia is still, in respect to this dis- 
 ease, a menace tp the rest of the world. 
 
 Ever since vaccination began to be , performed, there has 
 existed among a small number of individuals, opposition to it. 
 This is to be ascribed rather to perverseness than to reason. 
 In the early days antivaccinationists claimed that the 
 tendency of vaccination was to cause "bovine characteristics 
 to appear in children ; that they developed horns, hoofs, and 
 tails, and bellowed hke cattle." In recent years this class of 
 people have denied the efficacy of vaccination in preventing 
 smallpox — a denial that is overwhelmingly refuted by 
 facts — and they assert that a variety of diseases result 
 from the practice. In the early years, with the frequent 
 habit of employing the virus taken from a human being and 
 the none too cleanly treatment of the wound, there existed a 
 certain element of danger of this kind. But this danger is 
 now practically ehminated with the use of proper virus taken 
 from young healthy calves, and of aseptic methods. In these 
 days it is little less than criminal not to give to our children 
 the protection which scientific medicine here offers. 
 
 The next step in vaccination for human diseases was taken 
 by Pasteur with hydrophobia or rabies. While the victims 
 of rabies have never been numerous, there has always existed 
 a popular horror of it because of its frightful symptoms and 
 the certainty of its fatal ending. I well remember my own 
 and my playmates' youthful fear of the mad dog — the mad 
 dog that was always possible but never met with. Many 
 remedies have been recommended for its bite. Galen advised 
 a preparation of the eyes of crayfishes, and Pliny, the elder, 
 one of the livers of mad dogs. Not unfrequently those af- 
 fected by the disease have been shot, poisoned, or suffocated. 
 From classical times cauterization of the wounds has been the 
 
TREATMENT OF INFECTIOUS DISEASES 101 
 
 most frequent form of treatment. But no method was ever 
 certain. Pasteur shared the popular feeling in regard to the 
 disease, and in 1880 undertook its study. He never succeeded 
 in seeing its germ, nor is it certain that any one has seen it, 
 but he found that its seat is the brain and spinal cord. Bythe 
 successful inoculation of the virus into rabbits he could in- 
 crease its virulence up to a fixed point, and by removing from 
 an infected animal the spinal cord and drying it, the virulence 
 of the virus contained within it could be greatly diminished. 
 This gave him the key to the practical application of his 
 knowledge. If during the long incubation of the disease 
 when introduced by means of the bite of a rabid animal, 
 which averages some six weeks, he could effect within the 
 body the growth of an attenuated virus, he might forestall 
 the dreaded attack. He succeeded in doing this in dogs, and 
 was able to afford them absolute and certain protection. 
 Then came the extension of his method to a human being. 
 Pasteur's hesitancy and agony of mind in this step have been 
 told to the world. On March 28, 1885, he wrote to a friend: 
 "I have not yet dared to treat human beings after bites from 
 rabid dogs ; but the time is not far off, and I am much in- 
 clined to begin by myself — inoculating myself with rabies 
 and then arresting the consequences ; for I am beginning to 
 feel very sure of my results." On July 6 a young Alsatian 
 lad was brought by his mother to Pasteur's laboratory, shock- 
 ingly bitten by a dog, and though "divided between his hopes 
 and his scruples, painful in their acuteness," he at last re- 
 solved to attempt to save the lad from what he felt would be a 
 certain and terrible death. The first inoculation of a very 
 weak virus was made, and day by day a preparation of con- 
 stantly greater virulence was used. During the period of ten 
 days' treatment "Pasteur was going through a succession of 
 
102 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 hopes, fears, and anguish." In the midst of it all he wrote to 
 his son-in-law: "I think great things are coming to pass. 
 . . . Perhaps one of the great medical facts of the century 
 is going to take place." The boy left the laboratory well and 
 apparently protected, but not until weeks after did peace of 
 mind come to the man who had dared to bring to courageous 
 completion his long research. In the autumn of the same 
 year the story of his success had so far spread that he found 
 himself beset on every side by requests for treatment which 
 he could not refuse, and the extensive employment of his 
 method was begun. Now it has become world-wide. 
 
 The procedure followed by the New York Board of Health 
 in treating persons bitten by rabid animals is as follows in mild 
 cases. In more severe cases stronger virus is used at first, 
 and the treatment is continued for a longer time : 
 
 
 
 
 Dtieation op 
 
 
 
 Dat of 
 
 Tbbatment 
 
 Deting or Infected 
 
 Spinal Cobd in 
 
 Days 
 
 Quantity of Viktjs 
 Injected ' 
 
 1 
 
 
 
 14 and 13 ^ 
 12 and 11 ' 
 
 6 e.c. 
 
 2 . 
 
 
 
 6e.e. 
 
 3 . 
 
 
 
 10 and 92 
 
 6 e.c. 
 
 4 . 
 
 
 
 Sand 7 
 
 60.0. 
 
 5 
 
 
 
 6 
 5 
 
 2 e.c. 
 
 6 . 
 
 
 
 2 e.c. 
 
 7 . 
 
 
 
 4 
 
 2 0.0. 
 
 8 . 
 
 
 
 3 
 
 5 
 4 
 3 
 5 
 4 
 
 2 o.c. 
 
 9 
 
 2 CO. 
 
 10 
 
 2 CO. 
 
 11 
 
 2 CO. 
 
 12 
 
 2 0.0. 
 
 13 . 
 
 • ■ . 
 
 
 2 o.c 
 
 14 . 
 
 . ■ . 
 
 
 3 
 
 2 CO. 
 
 15 . 
 
 
 
 5 
 
 4 
 
 2 CO. 
 
 16 
 
 2 CO. 
 
 • Piece of cord i inch long, ground in 3 e.c. of salt solution. 
 
 ' Cords dried for nine days or more may be substituted for these cords. 
 
TREATMENT OF INFECTIOUS DISEASES 103 
 
 The most reliable statistics place the mortality of persons 
 bitten by rabid animals in Paris before the introduction of 
 Pasteur's treatment at 16 per cent, and the mortality of all 
 cases treated at the Pasteur Institute at 0.6 per cent. 
 
 During the past decade various investigators, but particu- 
 larly Sir Almroth Wright, have perfected a method of vacci- 
 nation that has proved of great value in the prevention of 
 typhoid fever. This consists of two, or sometimes three, 
 inoculations, at intervals of several days, of a preparation of 
 dead typhoid bacilli. An immunity extending over a period 
 of perhaps three years is thereby produced. The treatment 
 does not cure where the disease has already developed. It is 
 preventive rather than curative, but even where it fails to 
 prevent, it diminishes the severity and the mortality of the 
 disease. It has been extensively employed in the British 
 army in South Africa and India, and was introduced into our 
 own army two years ago. British statistics show a decline 
 in the number of cases from 5.75 per cent in the uninoculated 
 to 2.25 per cent in the inoculated, and a diminution in case 
 mortality from 26 per cent to 12 per cent. The results within 
 our own army are even more striking. Among the troops, 
 approximating 17,000 in number, who recently spent four 
 months in Texas and southern California, the entire 
 command having been inoculated, there were but two cases 
 of typhoid, one of which occurred before the process of 
 vaccination was completed. Among uninoculated civilians 
 living in the same localities the disease was common. 
 
 Several vaccines against cholera have been prepared. That 
 of Haffkine has been used extensively in India with pronounced 
 benefit. The likelihood of becoming subsequently infected 
 with the disease is thereby much diminished, and though, in 
 those attacked subsequent to the protective, inoculation, the 
 
104 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 percentage of fatality is nearly as great as in the uninoculated, 
 there is no doubt whatever about the protective value of the 
 treatment. 
 
 Haffkine's vaccine against the plague, which also has 
 been used with large numbers of persons in India, is even 
 more successful. The Indian sanitary commissioner says 
 of it in his report for 1904 : " That its value is great is 
 certain; not only does it largely diminish the danger of 
 plague being contracted, but, if it fails to prevent the attack, 
 the probability of a fatal event is reduced by one half." 
 Haffkine's figures for nearly 200,000 cases show a diminution 
 of case mortality from 60 per cent to 24 per cent. 
 
 Vaccines have been tried as curative rather than pre- 
 ventive agents, with promising results in pneumonia, chronic 
 cases of dysentery and diphtheria, and in various localized 
 affections, such as abscesses. Beginning with Koch's tuber- 
 culin in 1890, a considerable number of vaccines have been 
 devised during the past twenty years for the specific treat- 
 ment of tuberculosis. They all have raised hopes and have 
 had their advocates. Many of them have proved to be of 
 little or no value. It is now recognized, however, that 
 certain tuberculins are really curative, especially when they 
 are employed in the early stages of the disease or in cases 
 which are not advancing. They have also been used suc- 
 cessfully in detecting its presence. * 
 
 Hiss has recently attacked the infectious diseases boldly by 
 a new method. Recognizing that the white blood cells seem 
 to possess within their bodies substances that are capable of 
 neutraUzing the bacterial poisons, he reasoned that if these 
 substances could be supphed in quantity to an infected body, 
 this larger stock of its own weapons would enable it to cope 
 
 • For a fuller discussion, see p. 126. 
 
TREATMENT OF INFECTIOUS DISEASES 105 
 
 more successfully with the hostile germs. He has put his 
 theory into practice. From the injection of aleuronat into 
 the chest cavities of rabbits an abundant accumulation of 
 leucocytes results within a few hours. These are withdrawn, 
 water is added to them, and the extract of their substance is 
 ready for injection into infected organisms. Many experi- 
 ments on animals have warranted the extension of the method 
 to man, and, while it is still in the experimental stage, bene- 
 ficial results have been observed in pneumonia, erysipelas, 
 epidemic meningitis, and various affections caused by staphy- 
 lococci. 
 
 The discoveries which scientific medicine has made in 
 recent years in the realm of the infectious diseases are now 
 bringing to solution the long debated and puzzhng problem of 
 immunity. Certain diseases which are common in animals 
 never, or very rarely, appear in man ; in other words, man 
 possesses an immunity to them. This is true of rinderpest, a 
 disease prevalent in some countries among cattle, of dog dis- 
 temper, and of chicken cholera. Particular individuals, too, 
 appear to be immune to certain human diseases that may 
 attack other individuals. This is strikingly illustrated by the 
 differences among, races in respect to certain diseases. The 
 negro race is largely immune to yellow fever. Recovery 
 from an attack of an infectious disease has long been known 
 to bring with it a certain degree of immunity from a second 
 attack. Thus a person who has suffered from smallpox is 
 rarely attacked again by the disease. The protection which 
 typhoid fever, yellow fever, scarlet fever, and measles offer is 
 usually a life protection, although in the case of measles 
 and t3T)hoid fever this is not so assured as with smallpox. 
 We now know that by the aid of serums and vaccines it is 
 possible artificially to produce an immunity. With serums 
 
106 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 this immunity is of brief duration, lasting, for example, after 
 the administration of diphtheria antitoxin only from two 
 weeks to one month. How long it lasts after the use of 
 vaccines is largely unknown. Its duration, however, is 
 probably always less than that of the immunity acquired by 
 an attack of the disease, and it varies with individuals. 
 Thus it is popularly believed that vaccination against small- 
 pox protects the individual for about seven years, but the 
 protection may last for twice that period, or may be at an 
 end within a single year. The protection offered by vac- 
 cination against typhoid fever, cholera, and the plague 
 has been variously claimed to last for from six to eighteen 
 months, or in the case of typhoid for at least three years. 
 In the Hght of what we have learned concerning bacteria, 
 we can interpret many of these facts. Immunity appears to 
 be due to various conditions. The body cells may not po&- 
 sess a chemical aflBnity for the toxins given off by the micro- 
 organisms — in the language of Ehrlich, they may not possess 
 proper receptors — and hence the toxins may never be able 
 to enter into the cell substance and poison it. On the other 
 hand, while possessing proper receptors, the body cells may 
 possess at the same time the power of producing sufficient 
 ahtibodies to ward off an attack of the disease. Such an 
 immunity may be antitoxic, bacteriolytic, or phagocytic, 
 according as the defensive weapons are antitoxins, antibac- 
 terial substances, or opsonins. As I pointed out in the pre- 
 ceding lecture, the body naturally makes use of these three 
 methods in different degrees with different diseases. Scien- 
 tific medicine, in its efforts to aid the body, while endeavoring 
 to follow nature's lead, has succeeded in doing so in only a 
 partial degree. Thus, while nature's method of combating 
 diphtheria and tetanus seems to be through both antitoxins 
 
TREATMENT OP INFECTIOUS DISEASES 107 
 
 and opsonins, man has so far achieved striking success with 
 those diseases only by the aid of antitoxins. With cholera 
 and the plague, antibacterial substances appear to constitute 
 nature's chief medium, while at present opsonins are man's. 
 With typhoid fever maji's success has been obtained in the 
 same way as that of nature, through the agency of opsonins 
 and leucocytes. 
 
 But scientific medicine has learned a method of preventing 
 infectious diseases that is often more efficacious than the 
 treatment of the infected individual. This consists in keeping 
 the germs away from the individual. This is in fact the chief 
 office of the public hygiene and sanitation, of which we hear 
 so much in these modern days. The sources of drinking water 
 may frequently be controlled, and contamination may thus 
 be prevented. The simple storage of water in reservoirs 
 is a means of purification, and is probably the most common 
 method employed by cities in providing their inhabitants 
 with a pure water supply. Water may be filtered on a large 
 scale, and thus contaminating germs may be removed. This 
 plan is now followed by the cities of London, Berlin, Hamburg, 
 Lawrence in Massachusetts, and Albany in this state. For 
 the home, efficient house filters, such as the Berkefeld and the 
 Pasteur, are now readily obtained, and the boihng of water is 
 efficacious. The problem of pure milk for the multitude is 
 not easily solved. While milk is reasonably pure within the 
 udder of the healthy cow, it always becomes contaminated 
 in the process of removal, and, being a hquid mixture of easily 
 digested food-stuffs, it is an excellent medium for the multi- 
 pHcation of bacteria. Even the certified milk obtainable 
 in the city of New York contains on an average from 1000 to 
 5000 bacteria in every cubic centimeter, and the same quan- 
 tity of ordinary milk obtainable in the shops frequently holds 
 
108 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 during hot weather several millions. More than two hun- 
 dred varieties of bacteria have been found in such milk. 
 While many of these are probably innocuous, experiments 
 show that the feeding of milk heavily laden with bacteria to 
 young children endangers their health, and even their lives. 
 The one practicable method of destroying bacteria present in 
 milk is that known as pasteurization, which, when properly 
 performed, consists in heating the milk to a temperature of 
 approximately 60° C. (140° F.) for some twenty to thirty 
 minutes. This is sufficient to destroy the germs of tuber- 
 culosis, typhoid fever and diphtheria, and many other organ- 
 isms, and does not materially affect taste, nutritive proper- 
 ties, and digestibility. Pasteurization is practicable for the 
 educated consumer, and it may prove to be so on a large scale 
 by a municipality. But it alone does not suffice, and the 
 rigid inspection of dairies also appears to be essential to the 
 securing of suitable milk for the multitude. The spread of 
 rabies may be most efficiently prevented by the muzzling of 
 all dogs for a definite period and the examination of all alien 
 dogs introduced into the country. This is most readily 
 practised in a restricted area. By this method England has 
 practically eliminated rabies from her territory, and hence 
 needs no Pasteur Institutes. Plague may be in part pre- 
 vented by the destruction of rats. The most practicable 
 means of ehminating malaria and yellow fever consists in 
 destrojdng the possible breeding-places of mosquitoes. The 
 same is true, but to a less extent, of typhoid fever and cholera 
 in relation to the common house fly ; and the present crusade 
 against this pest is worthy of all encouragement. 
 
 The proper attitude of society toward bacteria-carriers is 
 not easy to determine. At present no form of treatment 
 seems to insure the complete destruction of the bacteria 
 
TREATMENT OF INFECTIOUS DISEASES 109 
 
 with which they are afflicted. It would be difficult to con- 
 vince law-makers that such persons ought to be placed in de- 
 tention, and yet there seems no reason to doubt that they con- 
 stitute a source of menace to public health. But society 
 can and ought to see to it that every case of a developed germ 
 disease, however mild it may be in the individual, is largely 
 isolated from human contact. This should be done even with 
 such apparently trifling ailments as "colds," which, there is 
 reason to believe, may harbor the germs of more harmful 
 conditions. Every case of an infectious disease may be a 
 center for the infection of others, and, by its isolation, the 
 possible evils arising from it may be obviated. By such 
 intelhgent cooperation society can aid scientific medicine 
 in the ultimate banishment of one of the chief causes of 
 human misery. 
 
VI 
 
 THE PBOBLEM OF CANCEK AND OTHER PROBLEMS 
 
 Those who have had sufficient persistence to follow the 
 lectures of this course so far must necessarily have been im- 
 pressed with the fact that a very large numBer and variety of 
 medical problems, which have puzzled the world for centuries, 
 have either been solved completely in recent years, or the way 
 of their solution has been pointed out. With others medical 
 science has not yet been so successful, and it is some of these 
 others that I wish now to consider. I may say at once that 
 present does not mean future absence of success. On the 
 contrary, it means the opposite. I know nothing that is 
 so conducive to a cheerful optimism in these present days as 
 the pursuit of science. The laboratory is the habitation of 
 buoyancy, enthusiasm, and hope. Its occupant has no moral 
 right to be despondent, and, if he is so, there is surely something 
 pathological in the activities of his brain-cells. Actually, 
 however, one rarely meets with a pessimistic man of science. 
 The experience gained in past advance but makes easier and 
 more certain the way of advance in the future. Just as a 
 bacterium within the body is a chemotactic center toward 
 which leucocytes flock, so an unsolved problem in science 
 draws investigators toward it. This is as true in medical 
 science as elsewhere, and if a disease still progresses, it is a 
 pretty sure sign that ere long something effective will be 
 put in its way. 
 
 One of these unsolved problems about which we are now 
 
 110 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 111 
 
 hopeful is the great problem of cancer. To laymen the word 
 is one of the most sinister in all medicine, bringing up a pic- 
 ture of a helpless being, harboring unwillingly a rapacious 
 object, which eats its way through tissues and saps vitality 
 until death brings the inevitable end. The picture is need- 
 lessly exaggerated, and yet it cannot be denied that it is 
 sometimes true. Cancer is one of the strangest and appar- 
 ently most lawless of vital phenomena. Picture to yourself 
 the growth of the human body. From a single ovum there 
 arises by continued division a mass of seemingly similar cells. 
 Within this mass differentiation occurs, and the cells take 
 on diverse appearances and groupings : some become muscle, 
 some nerve, some gland, some bone, and some epithelium. 
 Simultaneously the rudiments of organs appear, and func- 
 tions begin to be specialized. The division of cells continues ; 
 all proceeds in an orderly way ; each tissue finds its place ; 
 and each organ, as it becomes perfected, becomes limited in 
 size and diversity, so that it may work most advantageously 
 for the good of the organism. At the age of about twenty 
 years the body has largely ceased to acquire new tissue ; the 
 period of active cell growth and division has nearly come to 
 an end ; the existing cells have learned what they are to do ; 
 and the real business of one's physical life proceeds according 
 to law and system. But when one half of the normal space 
 of life is passed, or even earlier than this, a strange thing may 
 occur. At some point cell growth and division may start 
 anew. But this time the process is not orderly, as in child- 
 hood, nor are the cells differentiated into tissues. It is 
 unbridled, rapid, often tumultuous, and it rudely interrupts 
 the orderly processes of life. The cancer-cells which appear 
 are not like other cells, but have peculiarities of their own. 
 The growing mass pushes its unwelcome way into the tissues, 
 
112 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 forcing them aside and pressing them back upon one another. 
 In the center of the mass softening and degeneration may 
 occur. Occasionally the cancer-cells may even act like canni- 
 balistic phagocytes, devouring the cells of the organism that 
 holds them. They make their way along the lymph-vessels 
 and the blood-vessels, either by growth or after release from 
 the main mass, and find new abiding-places, where they may 
 become centers for additional growth. • They seem to produce 
 deleterious substances, which pass out beyond the scene of 
 frenzied activity and poison the tissue-cells elsewhere. And 
 thus the delicately coordinated body is made the scene of 
 anarchy and riot. Anemia, weakness, and emaciation follow, 
 and the final result too often is death. 
 
 What is the cause of this strange outbreak ? In these days 
 of disease-germs our first thought is tha,t one of these low 
 organisms has invaded the body, has found a soil favorable 
 for growth, and is but exercising its innate right to prosper. 
 Many attempts have been made to find the hypothetical 
 germ for cancer. Many microscopes have been turned toward 
 the new growth, and it has been searched through and through. 
 Alien Uving objects have been met with in abundance. Now 
 this organism, now that, bacteria„yeasts, protozoa, and other 
 living things, and objects of unknown nature, have been found 
 both within and without the cancer-cells and have been 
 heralded as the long-sought germinal agent. But as surely 
 as each discovery has been announced, so surely has it been 
 discredited, and there never has existed any agreement as 
 to the identity of the assumed agent. In view of many facts, 
 it has now come to be believed by most pathologists that there 
 is no such thing as a germ of cancer, and that the cause must 
 be sought in a wholly different direction. So, too, cancer is 
 not now regarded as an infectious disease. 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 113 
 
 Is cancer contagious ? There has been in the past a wide- 
 spread pubhc impression that this dread disease may be 
 transmitted from its victim to others by contact of the per- 
 son or personal articles. Even physicians have believed this, 
 and some have tried to support it by clinical evidence. The 
 belief has even been so strong in some individuals as to stifle 
 their innate sense of mercy, and to cause them to treat their 
 aflaicted fellow-creatures as outcasts to be shunned, and to 
 make personal safety their ruling motive. Much has been 
 written regarding the existence of cancer-infected houses, in 
 which successive tenants have acquired the disease, and of 
 its coexistence among persons living together. A careful 
 examination of the evidence in the light of modern knowledge 
 has now brought general conviction to the minds of those best 
 qualified to know that the transmission of cancer by contagion 
 does not occur. Statistics show that the occurrence of two 
 cases within one family or one house is not more frequent than 
 is demanded by the law of chance. The presence of a case 
 within a family, therefore, need cause no fear of the acquisi- 
 tion of the disease by other members of the household. Much 
 anxiety is often expressed over the possibility of the inherit- 
 ance of the disease. Here again scientific medicine is reas- 
 suring. Cancer is not inherited, and statistics do not seem to 
 indicate that there even occurs an inheritance of a predisposi- 
 tion toward it. 
 
 Cancer is comparatively rare among savage races. It is a 
 disease of civilization, and as the storm and stress of civilized 
 life become more turbulent, it seems to become more frequent. 
 Apparently reliable statistics show that during the past half 
 century it has increased in frequency over the more highly 
 civilized part of the globe — in England, Scotland, Ireland, 
 Wales, France, Germany, Holland, Norway, Sweden, Den- 
 
114 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 mark, Switzerland, Italy, Austria, Australia, and the United 
 States. The niunber of deaths from cancer in every 100,000 
 of population from 1890 to 1900 increased in England from 
 67 to 82, and in that portion of the United States in which 
 there was adequate registration from 53 to 65. It occurs 
 more frequently among women than men, a fact that is asso- 
 ciated with the existence of the two most susceptible organs, 
 the uterus and the breast. In organs common to the sexes 
 it is more frequent among men. It is much more common 
 after the age of thirty-five than before. 
 
 Cancers constitute one group of a large number of patho- 
 logical growths, called tumors. If a tumor grows slowly, is 
 sharply localized, consists of cells resembling normal cells, 
 is not destructive to the surrounding tissues, and is com- 
 paratively harmless, it is called benign. A common example 
 of such a growth is a wart in the skin. If, on the other hand, 
 the tumor grows rapidly, spreads through and destroys the 
 normal tissues, recurs when removed, and impairs the general 
 health, it is called malignant, or a cancer. There exist several 
 varieties of malignant tumors, and the term cancer is tech- 
 nically limited to that variety which is called carcinoma, and 
 originates in epithelium. We shall here extend the term, as 
 is often done, to include all malignant tumors. The cells 
 of which a cancer is composed differ both structurally and 
 functionally from normal speciaUzed tissue-cells and appear 
 to be more primitive, more embryonic in character. 
 
 A vast number of hypotheses have been proposed regarding 
 the place, the manner, and the causative conditions under 
 which cancers arise. It has been suggested that they have their 
 origin in minute islands of primitive cells, actual remnants 
 of the embryo, which were left unchanged when the differen- 
 tiation of tissues occurred, lie dormant during all the years of 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 115 
 
 childhood, youth, and early adult life, and later burst into 
 unbridled activity. This was the view of the great German 
 pathologist, Cohnheim. It has been suggested that the 
 forerunners of cancers are groups of cells that have become 
 misplaced or separated from their proper physiological con- 
 tinuity with other cells. It has been suggested that the first 
 step in the growth of cancers is a degeneration of normal cells 
 into cancer-cells ; there is probably truth in this notion. It 
 has been suggested that the cells destined to give origin to 
 the cancer are sports, the offspring of cellular mutations. It 
 has been said that the cancer-cells are those that have hitherto 
 lived a normal life, but have now lost their habit of work and 
 gained a habit of growth. Perhaps the sudden growth is 
 only a manifestation of normal forces that have hitherto 
 been held in restraint, and are now released; or these 
 forces may have suddenly become increased beyond their 
 normal bounds. All these and many other ideas regarding 
 the nature of cancerous growth have been proposed and are 
 now being actively discussed. External cancer appears to 
 develop frequently in localities in which there has been long- 
 continued inflammation or irritation. Thus an unhealed and 
 constantly irritated wound, such as in the lip of an inveter- 
 ate pipe-smoker, may become the seat of a cancerous growth. 
 Sailors occasionally develop cancer as the result of the con- 
 tinued action of light on the skin. Long exposure to Roent- 
 gen rays is sometimes followed by the disease. It is widely 
 believed, Ukewise, that internal cancers result from previous 
 irritation ; that, for example, an ulcer in the wall of the stom- 
 ach is often a forerunner of a more serious cancerous growth. 
 It is hoped that much hght will be thrown upon the genesis 
 of cancer by a method of study that has been introduced 
 within the past year by Carrel and Burrows and their asso- 
 
116 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 dates at the Rockefeller Institute for Medical Research and 
 is now being employed in various laboratories. It consists in 
 growing the cancerous tissue in glass outside the animal body. 
 A drop of the plasma of fresh blood is placed within a small 
 shallow glass chamber, and is allowed to coagulate. A small 
 piece of a cancer removed from the body of a man or a 
 lower animal is placed within this nutrient liquid. The 
 preparation is covered with glass, sealed tightly, and laid in 
 an oven, which is kept at a uniform temperature equal to 
 that of the living body. Under the influence of the warmth 
 and abundant food, the remarkable power of growth pos- 
 sessed by the cancer-cells asserts itself. Soon they appear on 
 the edge of the tissue. Many of them migrate outward. 
 They multiply rapidly and push themselves out in long radi- 
 ating Unes into the clear plasma, and the extension of the 
 cancerous mass is revealed even to the naked eye. Within 
 twenty-four hours the area of the new growth has far 
 surpassed that of the original fragment. The latter may 
 even be removed, and the growth still continues. With the 
 microscope each step in the process may be followed with ease. 
 
 While a cancer upon the surface of the body may be seen 
 in its early stages, one of the difficulties attendant upon its 
 presence within the interior is that of detecting it before it 
 has become grossly obvious. Facts have recently been dis- 
 covered which indicate that the cancer reveals its presence 
 by the appearance in the blood of certain characteristic sub- 
 stances. While the existence of these substances does not 
 seem to be confined solely to cancerous conditions, there is 
 reason to think that in them we have a valuable auxiliary, 
 although not an infaUible aid, in the diagnosis of this disease. 
 
 Let us suppose that a cancer has appeared in an individual, 
 and has been duly discovered. What is to be done ? The 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 117 
 
 most common procedure is to call in the surgeon and have him 
 cut out the offending object; and of all known methods of 
 treatment this is the most generally efficacious. If it be 
 done in the early stages of the growth, before the tumor has 
 become complex and has spread far from its place of origin, and 
 if care be taken to remove it completely, without leaving rem- 
 nants to act as centers of future infection, the surgical opera- 
 tion may be wholly effective and forever avert future trouble. 
 But a late resort to the surgeon's knife, or a slovenly operator, 
 although the main mass of the tiunor may be removed, 
 may only hasten the fatal ending. It may often happen, 
 however, that it is not practicable to resort to surgery. 
 Sometimes the disease has progressed too far, has permeated 
 too much of the body tissue, or has seriously involved essen- 
 tial organs ; sometimes it has so attacked the surface of the 
 body that surgical removal would result in excessive dis- 
 figurement ; sometimes the patient possesses ineradicable 
 objections to surgical treament ; and sometimes the physician 
 has reasons for believing that a better way than through sur- 
 gery can be employed. Hence methods have been devised 
 with a view of destroying the new growth in situ. These 
 methods are rendered practicable by the fact that the cancer- 
 cells appear to be more sensitive to destructive agents than 
 are the normal cells, and hence may be killed while the body 
 cells among which they lie remain uninjured. Various 
 destructive agents have been employed — caustic chemical 
 substances, such as caustic potash or arsenious acid; the 
 excessive heat of the surgeon's cautery ; excessive cold, such 
 as may be obtained from liquid air or frozen carbonic acid ; 
 the electric current; X-rays; and radium. All of these 
 agents have been used abundantly ; all have their enthusiastic 
 advocates; and probably all are of some degree of value. 
 
118 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 although opinions differ greatly both as to their comparative 
 merits and the circumstances under which they should be 
 employed. There is, however, a general consensus of opin- 
 ion among leading men of medicine that treatment by drugs 
 accomplishes no more than a rehef of specific symptoms, and 
 is never curative. 
 
 During the last decade the investigation of cancer has taken 
 on a wholly new aspect, because of the fact that it has been 
 found possible to transplant certain varieties of malignant 
 tumor from one animal to another. A bit of tumor is taken 
 from the body of an animal in which it may have appeared 
 spontaneously, is transferred to another animal, and there is 
 engrafted within the tissues, where it adheres and proceeds 
 to grow. Thus is made possible the method that is most 
 effective in studying the phenomena of nature, the method 
 of experimentation, in which the phenomenon can be pro- 
 duced at will and its conditions can be controlled. It is 
 interesting to observe the reaction on scientific investigators 
 of the discovery of this fact with regard to tumors. Eagerly 
 and enthusiastically and hopefully they have turned toward 
 the new field that has thus been opened up. Money has 
 been contributed ; new laboratories have been founded ; old 
 laboratories have been reorganized; other researches have 
 been laid aside ; and a concentrated, forceful move to solve 
 the cancer problem has been inaugurated. Of institutes or 
 laboratories for the investigation of cancer special mention 
 should be made of those in Copenhagen, Frankfurt, Heidel- 
 berg, Berlin, Paris, London, Buffalo, the Rockefeller Insti- 
 tute for Medical Research in this city, and the Universities 
 of Columbia, Cornell, Harvard, and Pennsylvania. The 
 latest foundation, and one of the most hberal, is the George 
 Crocker Fund, recently bequeathed to Columbia University. 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 119 
 
 Those who began the new line of investigation are Leo Loeb 
 of this country, and Jensen of Denmark, who in 1901 inde- 
 pendently demonstrated the possibility of employing animals 
 effectively for such work. 
 
 Ten years of this experimental work have not solved the 
 problem of cancer, but have contributed knowledge that is 
 full of importance and promise. One result already evident 
 is that the conditions of the growth of cancers are probably 
 very deUcately balanced. Thus only a few varieties of tumor 
 may be transplanted at all, and these to only a few individuals 
 of a few species of animals. Mice and rats are most susceptible 
 to their growth, and have been employed for most of the ex- 
 perimental work. An illustration of the delicacy of the bal- 
 ance under which they grow is found in the fact that a certain 
 variety of tumor which is very virulent for the mice of Ber- 
 lin will not grow in the mice of Christiania. Moreover, if 
 the susceptible variety of Berlin mice be bred in Christiania, 
 they soon lose their susceptibility and become resistant to the 
 same tumor. It is possible that this is due in part to a differ- 
 ence in the food supplied to the animals in the two cities : 
 mice in the laboratory in Berlin are fed chiefly on fat and pro- 
 tein, those in Christiania on carbohydrate. Such a fact 
 naturally suggests the probability that cancer will not grow 
 in the bodies of human beings unless the nutritive conditions 
 for such growth are exactly right". What these nutritive 
 conditions are remains still to be discovered, but it is being 
 shown that the growth of tumors under glass can be acceler- 
 ated and diminished by various chemical and physical altera- 
 tions of the medium in which they live. 
 
 The most promising of all the discoveries that the experi- 
 mental method has yielded is the fact that a resistance or 
 immunity to a tumor may be artificially produced. Occa- 
 
120 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 sionally an animal will recover spontaneously from a spon- 
 taneous or engrafted tumor. The cause of such recovery is 
 unknown. This has its counterpart in the human body, 
 where cancers occasionally recede and disappear of their 
 own accord. When it occurs in an animal, or even when a 
 tumor is merely present, it frequently follows that a second 
 tumor cannot be made to grow in the animal's body : by the 
 influence of the first growth the body has acquired an im- 
 munity to further foreign growths, not only of the same 
 variety, but even at times of other varieties as well. The 
 immunity thus acquired through a feeble tumor often pro- 
 tects against one of much greater virulence. Whether im- 
 munity to tumors, like immunity to bacterial diseases, i§ due 
 to the production of antibodies by the body cells, or is to be 
 explained otherwise, is not yet certain. If antibodies are 
 formed, they would probably exist in the blood, and we might 
 expect to find that the blood of such an animal possesses 
 curative powers. With one variety of foreign growth, which is 
 believed by many to be a tumor, this has actually been proved 
 to occur : blood that has been taken from an animal that has 
 recovered from such a growth and put into the vessels of 
 another animal which possesses a similar growth has been 
 found to make the latter to disappear. Such a fact may be 
 explained on the hypothesis that in the growth of tumors 
 protective antibodies arer actually formed by the body cells. 
 But certain facts, acquired also by animal experimentation, 
 do not seem to agree with this interpretation, and indicate 
 rather that acquired immunity to tumors may be due to a 
 consumption of the food that is essential to their existence. 
 Further work is needed along these promising hues of re- 
 search; but whatever the explanation of the immunity, the 
 fact that an immunity may be acquired at all is most prophetic 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 121 
 
 of the future discovery of a method of checking the growth of 
 and the curing of cancer in man. 
 
 As might have been expected, various investigators in 
 recent years have turned toward serums and vaccines with the 
 hope of finding in them the desired curative agent. The 
 composition of these has naturally varied with the theories 
 on which their authors have proceeded. Thus, it has been 
 observed that if an individual suffering from a malignant 
 tumor is attacked by erysipelas, the tumor frequently recedes 
 and may actually disappear. This suggests that erysipelas 
 is in some way antagonistic to the new growth. One inves- 
 tigator, acting on this suggestion, has actually treated tumors 
 by the injection of toxins derived from the germs of erysipe- 
 las, and has appeared to have a certain degree of success with 
 one of the less malignant types of new growth. Others, be- 
 lieving in the parasitic origin of cancers, have prepared serums 
 from various supposed causative organisms. Still others 
 have employed vaccines prepared in various ways. For 
 example, the actual substance of cancer-cells, killed, pulverized 
 and rubbed up in liquid, has been injected into patients suffer- 
 ing from cancerous growths. Some of these preparations 
 have apparently been successful in the treatment of animals, 
 and perhaps in isolated cases with human beings. But no 
 senma or vaccine has yet been devised that has achieved strik- 
 ing curative success with human cancers. AH are still wholly 
 in the experimental stage. 
 
 I have given you only a small fraction of the knowledge that 
 scientific medicine possesses regarding cancer, and I have 
 enumerated but a few of the many discoveries in this field 
 that have resulted from the introduction of the new methods. 
 The problem of cancer becomes larger every day. It has come 
 to be realized that it is a broad biological problem, and that 
 
122 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 it can be solved only by a fuller understanding of biological 
 laws. There are two material obj ects to be studied, the cancer 
 itself and the body in which it occurs. There constantly 
 occur physiological interactions between these two, and the 
 nature of these interactions must be discovered. The pre- 
 vention or the cure of cancer is the goal that is of most general 
 human interest; and although the way is not clear, there is 
 every reason to believe that this goal will ultimately be 
 reached. Let us hope that the attainment of this practical 
 end will not be forced to wait upon an understanding of 
 the many other features of this great problem. 
 
 While cancer is increasing in frequency, another of the 
 major diseases of mankind, tuberculosis, is decreasing in most 
 civilized communities. Thanks to the efforts of modern 
 scientific medicine, the problem of tuberculosis is now well 
 understood, and its solution is plainly in sight. Tuberculosis 
 is an ancient malady. Even in the Hippocratic writings, five 
 hundred years before Christ, there is a famous treatise on 
 phthisis. There can be no question that the disease has 
 been responsible for more human deaths than any other single 
 agency connected with the life of man. Probably one human 
 being in every seven dies of it. Its ravages are appalling 
 in our own country, where a reliable and conservative esti- 
 mate ascribes to it not less than 200,000 deaths annually. 
 Moreover, it is estimated that we now have one million cases 
 of it, and that its annual cost is from $150,000,000 to 
 $200,000,000. Fifteen thousand persons die of it every year 
 within the state of New York, and of these ten thousand 
 die within our city. The results of autopsies indicate that 
 practically all persons have at least a touch of it at some period 
 in their lives. It may affect practically every organ of the 
 body; it is masked under many guises and diverse names. 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 123 
 
 The lungs are the most common seat of the disease, and here 
 the widespread name "consumption" is its most common 
 designation. 
 
 The modern scientific epoch in the history of tuberculosis 
 may be said to begin with the proof by Villemin, in 1865, of its 
 infectious nature. It was not, however, until 1882 that the 
 briUiant work of Koch demonstrated conclusively the bacillus 
 that is the germ of the disease. There have existed much 
 confusion and some difference of opinion regarding the rela- 
 tion of this bacillus as it occurs in man and domestic cattle 
 respectively. It may now be regarded as conclusively proved 
 that there exist two distinct types of the bacillus, the human 
 and the bovine types, both of which are capable of causing 
 tuberculosis in man. The genetic relationship of the two 
 varieties is not known. The human type belongs primarily 
 to the human body, and is the most common germ of the 
 disease in adults. The bovine type belongs primarily to 
 domestic cattle, and yet frequently thrives in the human body, 
 especially in children. The relative proportions of the two 
 in the human body are shown in the accompanying table. 
 It is there seen that while the human type greatly predomi- 
 nates in man, the bovine type is common in children. Pul- 
 monary tuberculosis, which is comparatively rare in young 
 children, is probably almost exclusively of human origin. 
 
 Relative Proportion of Human and Bovine Types of the 
 Bacillus of Tubbbculosis in 1038 Cases (Park) 
 
 Bovine 
 
 Adults, 16 years and over 
 Children, 5 to 16 years . 
 Children under 5 years . 
 
 0.8 per cent 
 3.0 per cent 
 5.6 per cent 
 
124 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 The bacillus has the reputation of being a sturdy creature, 
 very tenacious of life, but it is doubtful whether this reputa- 
 tion is wholly deserved. In the dried state it may remain 
 quiet but living for several months. It will resist a dry heat 
 of 100° C. (212° F.) for from twenty minutes to one hour, 
 and a moist heat, as in milk or water, of 60° C. (140° F.) for 
 perhaps fifteen minutes. Chemical germicides do not appear 
 to kill it quite as readily as other pathogenic bacteria. It has 
 a profound aversion to sunlight, the direct light of the sun 
 sometimes killing it within a few minutes ; when dried it may 
 remain alive in darkened rooms for as long as ten months or 
 more. Its favorable habitat, the human body, can by com- 
 paratively simple measures be made most distasteful to it. 
 
 Tuberculous human beings and tuberculous cows are the 
 chief sources of infection for man. Tuberculous human beings 
 give off sputum containing bacilli, which may be conveyed 
 to other human beings, both adults and children, by coughing 
 or by hands or lips, or may become dried and then transmitted 
 through the air. Tuberculous cows produce infected milk, 
 and this conveys the germs to children. Once within the 
 > body, the bacilli seek the most favorable localities, absorb 
 food, and multiply. As they increase they do not swarm 
 freely through the body, but prefer to remain localized in 
 colonies in the lungs, joints, bones, membranes, glands, and 
 other organs. They produce toxins, which are in some degree 
 sent broadcast, but exert their deleterious action chiefly within 
 the colonies. They stimulate the body cells to grow and 
 produce unusual types of cells ; leucocytes are attracted to 
 the spot ; and the strange admixture of native and foreign 
 elements, supported by a fibrillar network and largely devoid 
 of blood-vessels, constitutes the tubercle. Within it the body 
 cells and the bacilli do not live amicably. Each force tries 
 
PROBLEM OP CANCER AND OTHER PROBLEMS 125 
 
 to destroy the other, and the invaders frequently have the 
 greater success, causing the death and degeneration of the 
 body cells. Then one of two things may occur. The tu- 
 bercle may cease to advance, may develop an enveloping 
 capsule, and may become hard, quiescent, and innocuous. 
 On the other hand it may continue to progress ; a constantly 
 widening area of the surrounding tissue may become involved ; 
 other micro-organisms may invade the spot and lead to the 
 accumulation of pus ; if in the lungs, the growing tubercle 
 may break through the wall of an air passage, and the debris 
 of the degenerated tissues may be discharged, leaving a cavity ; 
 cavities of neighboring tubercles may fuse together; blood 
 vessels may rupture and hemorrhage may result ; and in the 
 course of time the destruction of tissue and the interference 
 with bodily functions may be so great as to cause death. 
 
 The body, however, possesses a very considerable power of 
 resisting the attacks of the tubercle bacilli. A healthy, vig- 
 orous, well-nourished person, living in sunshine, breathing 
 pure air, and exposed only occasionally to the germs, offers 
 a poor soil for their growth, while, on the other hand, little 
 air and light, underfeeding, fatigue, the constant use of alco- 
 holic liquors, and frequent exposure to the bacilli are favor- 
 able to them. Yet, even after they have obtained a foot- 
 hold, their course of development is very frequently checked 
 before it has gone far. This probably happens in the great 
 majority of individuals. The nature of this spontaneous 
 cure is not yet understood. The body cells seem to be stimu- 
 lated by the bacilH or their toxins to produce antibodies, but 
 comparatively Httle has yet been discovered concerning such 
 substances. Yet this lack of knowledge has not prevented 
 investigators from searching in all directions for means with 
 which to put a stop to this great scourge. The long list of 
 
126 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 drugs has been diligently searched, and it is now realized that 
 they cannot act specifically on the bacilli themselves or their 
 products. Such few drugs as are of use are of value in reliev- 
 ing the specific symptoms, such as the high fever and the 
 cough, or in making the body more resistant in general to 
 untoward conditions. As might have been expected, many 
 serums and vaccines have been devised for the specific treat- 
 ment of the disease. Of the serums those of Maragliano and 
 Marmorek are the most prominent, but there is no general 
 agreement that they or other serums are of real value. The 
 vaccines are more numerous. While differing in certain 
 respects, they are alike in consisting of some or all of the 
 products of the bacillus. The whole world was startled in 
 1890 when Koch announced the results of his experiments with 
 one of these vaccines, tuberculin, and it was widely believed 
 that at last the long-sought cure for consumption had been- 
 found. But the world's expectations were greater than those 
 of Koch. Too much was demanded of tuberculin. It was 
 used by the competent and the incompetent, grossly, irra- 
 tionally, and in cases that were beyond all aid. When the 
 world learned, what Koch had always known, that tuber- 
 culin was not a universal cure for consumption, the world, 
 even much of the medical world, turned upon and unjustly 
 denounced both the remedy and its maker. But here again 
 the pendulum swung too far. It was sure to go back, however, 
 and so it has. Tuberculin — which word has now become 
 the generic name for the more prominent tubercular vac- 
 cines — is prepared in various forms, which vary in composi- 
 tion and physiological action. It is being very widely used 
 as a means both of diagnosing and of treating the disease. 
 As a diagnostic agent its injection is followed by a rise of 
 temperature if tuberculosis be present, and by no such reac- 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 127 
 
 tion, or only a very slight one, if tuberculosis be absent. 
 This test for the presence of the disease is now employed con- 
 stantly with domestic cattle and frequently with human be- 
 ings. As to the therapeutic value of tuberculin, those who 
 have used it most intelligently testify to its worth. Thus 
 it has been used with a considerable number of patients at 
 the Adirondack Cottage Sanitorium under the skilful direc- 
 tion of Trudeau since 1890, with the result that, while in the 
 incipient stage of the disease it seems to have made little 
 change, of the moderately advanced cases those who have 
 been discharged from the institution apparently cured number 
 six per cent when untreated, and twenty-seven per cent when 
 treated with tuberculin. Notwithstanding the partial suc- 
 cess of tuberculin, it must be granted that the ideal specific 
 remedy for tuberculosis has not yet been found, although 
 medicine has by no means given up the search. 
 
 But fortunately for the human race tuberculosis, when 
 compared lyith other infectious diseases, is peculiarly re- 
 sponsive to more general therapeutic measures. These con- 
 stitute the now well-known hygienic-dietetic method of 
 treatment. The three most pronounced features of this 
 method are rest, both physical and mental, combined with 
 carefully regulated exercise, liberal feeding, and an abundance 
 of fresh air. A change of climate is sometimes valuable, but 
 not essential. Life in a sanitorium insures a stricter adherence 
 to the principles of this treatment than life in the home. 
 Permanent improvement under it is never speedy; it may 
 demand from three months to three years, and a cure may 
 require still more time. Naturally the incipient or moder- 
 ately advanced cases are more favorable than those that are 
 far advanced. For wage-earners life in a sanitorium is often 
 impossible. This fact should cause no despair, for the treat- 
 
128 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 ment of the disease in the home has abundantly justified 
 itself, and here the dispensary and the visiting nurse have 
 proved a blessing. 
 
 One of the most remarkable and most hopeful philanthropic 
 movements that has ever been undertaken is the present 
 campaign against tuberculosis, which has been stimulated 
 directly by the achievements of scientific medicine. Many 
 countri'es are engaged in it, but it has been most highly or- 
 ganized in the United States and the state and city of New- 
 York. For national work the National Association for the 
 Study and Prevention of Tuberculosis is preeminent; for 
 the state of New York the State Charities Aid Association ; 
 and for the city of New York the Committee on the Pre- 
 vention of Tuberculosis of the Charity Organization Society. 
 There now exist in the United States nearly 500 associations, 
 300 special dispensaries, and 400 special sanitoria and hos- 
 pitals, with nearly 25,000 beds, all devoted to specific anti- 
 tuberculosis work. During 1909 the various state legislatures 
 appropriated a total of about $4,000,000 for the campaign. 
 Each year shows an increase over all preceding figures. 
 Although this work must ultimately have a preventive effect 
 on the disease, it has been inaugurated for too short a time 
 to afford undoubted statistical results — unless the following 
 figures are so interpreted. 
 
 Number op Deaths from Tuberculosis per 100,000 op Popu- 
 lation IN THE State of New York 
 
 Year 
 
 Urban Deaths 
 
 Rdbal Deaths 
 
 1907 
 
 1908 
 
 1909 
 
 1910 
 
 189.4 
 184.4 
 175.5 
 165.5 
 
 126.6 
 124.3 
 121.1 
 121.3 
 
PROBLEM OP CANCER AND OTHER PROBLEMS 129 
 
 The table shows that the decrease in the mortality of this 
 disease during the past four years has been more rapid in 
 urban than in rural communities. The cause of this is not 
 clear, unless it be ascribed to the greater efficiency of the 
 antituberculosis measures employed in cities. 
 
 While the forces engaged in this work aim to provide treat- 
 ment for those unfortunate persons who are afflicted with the 
 disease, it is recognized that the surest way of solving the 
 problem of tuberculosis is to prevent its extension, and energy 
 is now expended chiefly in this direction. It is realized that 
 the most prolific centers of infection are the home and the 
 crowded places of business, where the infected person comes 
 into intimate association with the uninfected and the bacilli 
 may readily be transferred from the one to the other. It has 
 been estimated that fifty-one per cent of all children in 
 tuberculous families acquire the germs of the disease. The 
 control of the germ is, therefore, the essential factor in the 
 prevention of the disease. I have mentioned the fact that 
 the total mortality from tuberculosis is gradually diminish- 
 ing. This is strikingly shown in some of those communities 
 in which the segregation of advanced cases in institutions 
 has been practised, as, for example, in England, Scotland, and 
 Wales, and it seems reasonable to associate this manner of 
 dealing with the disease and the decrease in its death-rate 
 as cause and effect. The present efforts of those who are 
 directing the war against it are being expended partly in 
 educating the people concerning it, and partly in securing the 
 establishment of hospitals for advanced and incurable cases 
 and of sanitoria and dispensaries for those who may still be 
 cured. When public opinion will sanction the segregation of 
 all dangerous cases, and when hygienic conditions of living 
 have become such as to prevent susceptibility to the disease, 
 
130 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 the days of this ubiquitous and deadly bacillus will be num- 
 bered. 
 
 Pneumonia is an acute infectious disease which still offers 
 a serious problem to scientific medicine. The pneumococcus 
 seems to be the chief causative agent in both the so-called 
 lobar and lobular types of the disease, but several other micro- 
 organisms may be present. The fact that the pneumococcus 
 is one of the most universal and ordinarily innocuous inhabit- 
 ants of the air passages of healthy persons indicates that its 
 presence alone is not the sole essential factor in the incidence 
 of the disease. The body must contribute favorable condi- 
 tions for the bacterial growth. In lobar pneumonia the bac- 
 teria pass into the blood, but are localized chiefly in the lungs, 
 where they cause severe inflammation, resulting in the clogging 
 of the alveoli or air-cells with foreign substance, and serious 
 interference with the respiratory exchange between air and 
 blood. Intensely poisonous bacterial toxins, which appear 
 to be endotoxins rather than exotoxins and incapable of 
 stimulating the body cells to the production of antitoxins, 
 are given off, probably on the death of the germs, and seri- 
 ously affect the heart and other organs. Opsonins are prob- 
 ably produced, and the lungs become the ground of a fierce 
 contest between leucocytes and germs, in which the individual 
 too often succumbs. Antibacterial serums have been prepared, 
 but have not met with great success. Vaccines, especially 
 those prepared from a culture of the germs taken from the 
 patient himself, appear to act favorably in certain cases. 
 But no specific treatment is markedly effective, and the pneu- 
 mococcus continues to take its abundant toll of human lives. 
 
 Cancer, tuberculosis, and pneumonia illustrate well the 
 variety and complexity of the conditions that scientific medi- 
 cine has to meet in its campaign against disease. Questions 
 
PROBLEM OF CANCER AND OTHER PROBLEMS 131 
 
 of physiology and pathology, of bacteriology and pharma- 
 cology, of chemistry and physics and general biblogy, of 
 psychology, ethics, and sociology, have to be asked and 
 answered. The unsolved problems are still many, and all 
 encouragement should be given to the devoted men who are 
 laboring to accomplish their solution and the manifold bless- 
 ings that will thereby be conferred upon mankind. 
 
VII 
 
 FEATURES OP MODERN SURGERY 
 
 The most dramatic chapter in medicine is that of surgery. 
 An old English proverb runs, "A good surgeon must have an 
 eagle's eye, a lion's heart, a lady's hand." If this were true 
 in the days of medievalism, it is much more so now. The 
 transfer from the medieval to the modern in surgery has 
 taken place within the memory of living men. It is true that 
 even before this generation boiling oil was no longer poured 
 into wounds to assist the healing process, but there were two 
 features that still were prominent, as they had been prominent 
 from neolithic times. These were the pain of the operation 
 and the uncertainty of its outcome, owing to the almost inevi- 
 table septic conditions that followed it. These two features 
 have now been almost wholly eliminated by the discovery 
 of anaesthesia and asepsis, the two most important general 
 surgical advances of our time. 
 
 That the early surgery was a matter of agony for the patient 
 can easily be conceived and is abundantly attested by litera- 
 ture. We read of "the excruciating tortures and writhings 
 and shrieks of patients on the operating table." An eminent 
 American surgeon has written of operations before anaes- 
 thesia : " Prior to that time a surgical operation was attended 
 with horrors which those who live in these days cannot 
 appreciate. He was the best surgeon who could perform any 
 operation in the least possible time. The whole object of 
 
 132 
 
FEATURES OF MODERN SURGERY 133 
 
 new methods of operating was to shorten the period of 
 frightful agony which every patient had to endure. Every 
 second of suffering saved was an incalculable boon. To sub- 
 mit to any operation required then a heroism and an endur- 
 ance which are almost incomprehensible to us now. All of 
 the more modem, deliberate, careful, painstaking operations, 
 involving minute dissection, amid nerves and blood-vessels, 
 when life or death depends on the accuracy of almost every 
 touch of the knife, were absolutely impossible. It was be- 
 yond human endurance quietly to submit one's self for an 
 hour, for an hour and a half, for two hours, or even longer, 
 to such physical agony." Even those who operated felt the 
 horror of it. It is related of the famous English surgeon, 
 Cheselden, that "he always before an operation felt sick at 
 the thought of the pain he was about to inflict." Various 
 attempts were made to allay the pain. The ancient Euro- 
 peans used mandrake, the Chinese and East Indians hasheesh. 
 Later other drugs were employed, among them liberal doses 
 of opium or of alcoholic drinks. But all these were far from 
 ideal. The situation, however, was completely and quickly 
 changed by the success of an operation in the year 1846, 
 at the Massachusetts General Hospital in Boston, when the 
 eminent surgeon, Warren, painlessly removed a tumor from 
 the neck of a man who had been put under the influence of 
 ether by the dentist, Morton. This operation created great 
 excitement in the surgical world, and, among other results, 
 stimulated Sir James Simpson of Edinburgh to experiment 
 with a stronger anaesthetic, chloroform. His success caused 
 the introduction of chloroform into surgical procedure in the 
 year following that of ether. The use of these agents soon 
 spread far and wide, but their universal employment did not 
 occur without the inevitable opposition to innovations. 
 
134 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 Such opposition came from two sources. Certain men of 
 medicine objected to the new practice on the singular grounds 
 that "pain during operations is, in the majority of cases, even 
 desirable, and its prevention or annihilation is for the most 
 part hazardous to the patient; " "pain should be considered as 
 a healthy indication ... an essential concomitant with 
 surgical operations . . . the natural incentive to reparative 
 action." But more singular objections than these were 
 raised on religious grounds. It was argued that to avert pain 
 was to thwart the will of God, and biblical passages were 
 brought forward to support the contention. To controvert 
 the various objections, even the defenders of anaesthesia 
 were forced to singular lines of argument. Thus, Sir James 
 Simpson wrote as follows: "Those that urge, on a kind of 
 reUgious ground, that an artificial or anaesthetic state of 
 unconsciousness should not be induced merely to save frail 
 humanity from the miseries and tortures of bodily pain, 
 forget that we have the greatest of all examples set before 
 us for following out this very principle of practice. I allude 
 to that most singular description of the preliminaries and 
 details of the first surgical operation ever performed on man, 
 which is contained in Genesis ii, 21. 'And the Lord God 
 caused a deep sleep to fall upon Adam ; and he slept ; and 
 he took one of his ribs, and closed up the flesh instead thereof.' 
 In this remarkable verse the whole process of a surgical 
 operation is briefly detailed. But the passage is principally 
 striking, as affording evidence of our Creator himself using 
 means to save poor human nature from the unnecessary 
 endurance of physical pain. ' It ought to be noted ' (observes 
 Calvin, in his commentary on this verse), 'that Adam was 
 sunk into a profound sleep, in order that he might feel no 
 pain.'" Whichever party had the best of the argument, 
 
FEATURES OP MODERN SURGERY 135 
 
 common sense prevailed, and the new era of painless surgery 
 was quickly inaugurated. One early result of this was a 
 great increase in both the number and variety of operations. 
 Ether and chloroform have continued as the favorite general 
 surgical anaesthetics, though nitrous oxide and other sub- 
 stances are sometimes employed. Still others are used to 
 great advantage for the purpose of producing insensitiveness 
 at the immediate site of the operation, and thus obviating the 
 profound effects of an anaesthetic that pervades the whole 
 body. Among such local anaesthetics cocaine is the most 
 important. Of late years an entirely new method has been 
 advocated for rendering insensitive the lower parts of the 
 body. This consists in injecting a suitable drug into the 
 lower portion of the spinal canal, where it temporarily para- 
 lyzes the outgoing nerves and even the spinal cord itself, and 
 prevents the passage of nervous impulses to the brain. Co- 
 caine, tropococaine, novocaine, stovaine, and other drugs 
 have been so employed. Notwithstanding the fact that the 
 method has been subjected to much and varied criticism, it 
 seems to have a definite field of usefulness. 
 
 But with the discovery of practicable anaesthetics the battle 
 was only half won. The operation itself had lost much of its 
 horror, but the tragedy of the subsequent days was unchanged. 
 There were the almost inevitable suppuration of the wound, the 
 putrefaction and sloughing off of tissue, the sickening odor, 
 the high fever, the danger of hemorrhage, the slow healing, 
 the complications of blood poisoning, erysipelas, gangrene, 
 and tetanus, the physical and mental anguish, and the uncer- 
 tainty of the final outcome. The mortality from major 
 operations was from fifty to one hundred per cent. The open- 
 ing of the abdomen, the chest, or the skull was undertaken 
 only in extreme cases, and "was almost equivalent to signing 
 
136 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 the death warrant of a patient." The wounds of two bloody- 
 wars, our Civil War and that of France and Germany, testi- 
 fied to the impotence of septic surgery. But Pasteur's 
 studies had already proved that fermentation and putre- 
 faction were due, not to "gases, fluids, electricity, magnetism, 
 ozone, things known or things occult," but solely to micro- 
 scopic living germs. The English surgeon Joseph Lister, 
 holding a professorship at Glasgow, had become acquainted 
 with Pasteur's work and, a firm believer in what certain 
 sceptics called "mythical fungi," reasoned that if the germs 
 caused putrefaction elsewhere they could do the • same in 
 wounds. He therefore conceived the idea of bathing wounds 
 with, and applying to them dressings of, carbolic acid for the 
 purpose of killing whatever germs were already present. 
 He applied this to several cases of compound fracture with 
 marked success in inducing healing without suppuration, 
 and thus in 1867 antiseptic surgery had its birth. To Lister, 
 who continued for years actively to experiment, has been 
 granted great honor in all civilized countries, and he has had 
 the privilege of seeing surgery completely revolutionized by 
 the stimulus of his labors. In the rise of bacteriology it has 
 been shown that the suppurations, putrefactions, blood 
 poisonings, erysipelas, and other untoward sequelae of the 
 early surgical operations were caused not by anjrthing 
 already present in the body of the patient, but by bacteria, 
 which were introduced into the wound at the time of the 
 operation, These came not so much from the air as from the 
 surgeon and his implements. The warm, moist, nutritive 
 surfaces afforded most favorable conditions for growth and 
 multiplication. The bacteria throve, some of them spread 
 throughout the body, and each species produced its charac- 
 teristic symptoms. Thus the old-time surgeon, with his hands, 
 
FEATURES OP MODERN SURGERY 137 
 
 his instruments, his sponges, his lint, and his bandages, was 
 teeming with disease germs, and the wonder of it all is that 
 the mortality resulting from his unclean, even though well- 
 intentioned, work was not greater than it proved to be. Not 
 until Pasteur and Lister pointed it out did civilized man know 
 what constitutes real cleanliness. Lister later introduced the 
 method of maintaining throughout the surgical operation a 
 delicate spray of carbolic acid in the air over the wound. Still 
 later the use of germicidal agents during the process of operat- 
 ing was found to be unnecessary. Strict cleanliness was 
 proved to be sufficient, and antiseptic surgery gave place 
 to the aseptic surgery of to-day. 
 
 The absolute sterility, or freedom from bacteria, of all 
 things that come into contact with the woimd is the sine qua 
 non of the successful surgical operation of the present day. 
 In order to insure this, the patient, the surgeons, the attend- 
 ing nurses, the room, the operating-table, the instruments, 
 the ligatures, and the dressings are elaborately prepared. 
 Mechanical cleansing, chemical germicides, and heat are em- 
 ployed in removing or killing the bacteria. All sheets, 
 towels, cotton wool, gauze, and bandages that may come into 
 contact with the tissues at the site of the operation, as well 
 as the clothing of the surgeons, assistants, and nurses, are 
 sterilized by being submitted to a high degree of heat in a 
 specially prepared oven. All instruments are thoroughly 
 boiled in an antiseptic solution, and are then dried on sterile 
 towels or are laid in a sterile liquid. Sea sponges, which were 
 formerly used freely, have now given place to sponges of 
 sterilized gauze; lint and old linen have been replaced by 
 sterilized cotton wool and muslin; sterilized catgut has be- 
 come the most common material for ligatures. The patient's 
 skin at the site of the proposed operation is thoroughly and 
 
138 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 repeatedly scrubbed with cleansing antiseptic agents. The 
 surgeon removes his outer clothing, and dons a sterilized gown 
 which covers his body. His head is encased in a sterilized 
 cap and frequently a sterilized mask, which covers the face 
 except the eyes, and prevents any contamination from the 
 mouth and nose. The hands and forearms are submitted 
 to most thorough and prolonged washing, are subsequently 
 soaked in antiseptic solutions, and are then covered with 
 sterilized rubber gloves. Surgical assistants and nurses 
 undergo a preparation scarcely less elaborate than do the 
 surgeons. When the environment is thus freed from bac- 
 teria, the operation proceeds, practically without the aid of 
 further germicides. 
 
 With pain and bacteria eliminated, the way was open for 
 surgery to develop along rational lines, and the advance of the 
 past forty years has been imexampled. No portion of the 
 body is longer regarded as inaccessible to the surgeon's 
 instruments. The most striking improvements have involved 
 the three great cavities of the body — the abdomen, with its 
 many organs of nutrition, the chest, with the lungs and heart, 
 and the cavity of the skull, containing the brain. 
 
 The abdomen can be freely opened without the former 
 inevitable peritonitis resulting, and can be thoroughly ex- 
 plored. The stomach can be opened; foreign bodies that 
 have been swallowed can be removed from it ; wounds in its 
 walls can be repaired ; ulcers, cancers, and other tumors 
 can be removed ; when the incoming and the outgoing open- 
 ings, those of the oesophagus and the intestine respectively, 
 have become constricted, they can be enlarged; if the 
 oesophagus has become permanently closed, a new entrance into 
 the stomach can be made from the outside through the abdomi- 
 nal wall, and food can thus be introduced ; if the stomach has 
 
FEATURES OF MODERN SURGERY 139 
 
 become too greatly dilated, tucks can be taken in its wall ; 
 if it sags, its ligaments can be shortened, or it can be stitched 
 to the wall of the abdomen; parts of it can be removed; 
 new connections can be made between it and the intestine — 
 a procedure that is now followed in a considerable variety 
 of conditions ; and lastly, in a number of extreme cases, the 
 stomach has been removed in toto, and the oesophagus and 
 the intestine have been joined directly. Operations analo- 
 gous to those of the stomach can be successfully performed 
 on the intestine, wounds being sewed up, portions of it several 
 feet in length being removed, new connections being made 
 between adjacent parts ; and, if necessary, external openings 
 can be made from it through the body wall. The intestinal 
 operation that has excited the greatest amount of popular 
 interest is undoubtedly that of the removal of the vermiform 
 appendix, which has raised this humble little organ to a posi- 
 tion of surgical prominence that is altogether out of propor- 
 tion to its physiological importance. The appendix is a 
 small tube, branching out from the large intestine near its 
 beginning and closed at the farther end. In certain of the 
 lower animals, as in the rabbit, it is large and is stored 
 with partially digested food. In man it is some three and 
 one half inches in length and one quarter of an inch in diame- 
 ter, and is a degenerate organ, of no great importance func- 
 tionally. It is a pity that it has not long since met the fate 
 of other of nature's remnants. It is peculiarly prone to in- 
 fection, and it is probable that bacteria are the chief factor in 
 the onset of inflammation which we call appendicitis. The 
 most common bacterium is the colon bacillus, the universal 
 bacterium of the large intestine, although septic organisms, 
 pneumococci, and tuberculosis bacilli are frequently found 
 there. The accusation that is commonly heard against seeds 
 
140 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 and other foreign bodies as the cause of appendicitis seems 
 to be unjust. While a mild inflammation of the appendix 
 may at times be allayed by external treatment, it is now 
 agreed by most physicians and surgeons that removal is the 
 one effective remedy, and that it^should not be long delayed. 
 The operation has been performed for about twenty-five years, 
 and is done with great ease and rapidity, a skilful operator 
 requiring only from fifteen to thirty minutes in uncompli- 
 cated cases. It is not regarded as dangerous if performed 
 early in the course of the disease and by a competent 
 surgeon. Under such conditions its mortality does not 
 appear to be above two per cent. 
 
 The liver has the most abundant supply of blood-vessels 
 of any single organ of the body, and it contains one quarter 
 of all the body's blood. Hence it might be supposed that its 
 surgery would be. difficult because of hemorrhage. Here, 
 however, nature's provision that the pressure of the blood 
 within the hepatic vessels is comparatively low assists the 
 surgeon, with his artificial means of preventing a loss of blood. 
 A variety of operations on the liver can be successfully per- 
 formed, such as the repair of injuries, the draining of abscesses 
 and of cysts due to parasites, and the removal of tumors. 
 In these and other operations it is sometimes necessary to 
 remove parts of the organ itself, and considerable portions 
 of it have thus been successfully taken away. Nature's 
 generosity to mankind is shown in the fact that the remaining 
 portion suffices to perform for the whole body all the im- 
 portant hepatic functions. It happens occasionally that the 
 liver settles down below its proper place or becomes freely 
 movable. In such conditions its suspensory ligaments can 
 be shortened ; it can be sewed to the abdominal wall ; or its 
 upper surface can be scarified and made to adhere to the 
 
FEATURES OF MODERN SURGERY 141 
 
 diaphragm; by these various devices the liver can be re- 
 stored to and anchored in its proper place. 
 
 One of the body's organs that frequently causes trouble 
 is the gall bladder. This is prone to become the site of the 
 formation of gall stones, which are concretions composed 
 largely of cholesterin, one of the waste products of bodily 
 activity. They frequently follow an attack of typhoid fever, 
 and the cholesterin is then deposited about the typhoid 
 bacilli which have tarried within the gall bladder. The 
 presence of gall stones excites inflammation within the 
 bladder, and their involuntary expulsion through the hepatic 
 duct is often accompanied by excruciating pain. Their 
 surgical removal is desirable, and within the last decade 
 the operation has become common. It consists either in 
 opening the gall bladder and removing the stones alone, or 
 in taking away the entire bladder itself. The mortality 
 from this latter operation is less than two per cent, and the 
 absence of untoward effects shows that the organ and its func- 
 tion as a storehouse for bile are not necessary to the body's 
 needs. 
 
 The spleen may likewise be totally removed without detri- 
 ment to health. Considerable portions of the pancreas may 
 safely be taken away. The kidneys are subject to a consider- 
 able variety of disorders that demand surgical treatment. 
 Such treatment includes sewing a kidney to the tissues of 
 the back, the repair of wounds, cutting into it, draining it, 
 the removal of calculi, and the removal of the kidney itself, 
 either ih whole or in part. The removal of both kidneys is 
 fatal. 
 
 Surgical operations on the chest or thorax and its organs 
 are rendered difficult, first, by the great liability of the parts 
 to infection, a liability much greater than that of the abdomi- 
 
142 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 nal organs, and secondly, by the peculiar mechanical condi- 
 tions that are presented. The cavity of the chest is divided 
 by delicate membranes into three separate compartments : 
 the right and left pleural cavities, occupied by the right and 
 left lungs; and between them the mediastinal space, containing 
 the heart, the large blood-vessels joining it, the thoracic 
 lymph duct, the oesophagus, the trachea, and certain large 
 nerves. By the respiratory movements of the walls of the 
 chest and the diaphragm below, the pleural cavities and the 
 air passages of the lungs are alternately enlarged and dimin- 
 ished, and air is alternately drawn through the nose or the 
 mouth and the trachea into the lungs and expelled by the 
 same route. At all times during health, even in extreme ex- 
 piration, the lungs are distended, now more, now less, yet 
 they always entirely fill the pleural cavities. But when 
 the chest wall is punctured, as by a wound, or a lung is 
 ruptured, as by the breaking down of a tubercle, air rushes 
 into the corresponding pleural cavity, and the lung collapses 
 like a torn balloon and becomes partially incapable of per- 
 forming its respiratory function. This condition, while 
 dangerous, is not fatal if the opposite lung and pleural cavity 
 are uninjured. In that event respiration, though diminished, 
 still goes on, and if the injury can be healed, the thoracic 
 air is absorbed and the affected organ later resumes its r61e. 
 A surgical operation on a lung involves entrance through 
 the thoracic wall, and the consequent hazardous interference 
 with respiration. Various devices have been introduced to 
 overcome this. Sometimes an intermittent or a continuous 
 stream of air is forced under pressure into the trachea and 
 the lungs, and thus respiration is maintained artificially 
 during the operation. Sometimes the body of the patient 
 and the surgeons are placed in a pneumatic cabinet, through 
 
FEATURES OF MODERN SURGERY 143 
 
 an opening in one wall of which the patient's head protrudes. 
 Thus he breathes air, as normally, under the prevailing at- 
 mospheric pressure. The air in the cabinet, however, is 
 maintained at less than this pressure, and thus both pleural 
 cavities can be safely opened without danger. While opera- 
 tions on other thoracic organs are now varied and numerous, 
 operations on the lung substance itself are still comparatively 
 limited. Nevertheless pathological growths within the 
 lungs are beginning to be successfully removed, and in va- 
 rious other diseased or injured conditions portions of the 
 pulmonary tissue have been taken away. Even the surgi- 
 cal treatment of tuberculous lungs is coming into favor. The 
 present outlook for an extended pulmonary surgery is dis- 
 tinctly hopeful. 
 
 The living beating heart is commonly thought to be a most 
 delicate organ, the slightest interference with which may lead 
 to serious consequences. Physiologists, however, have long 
 been accustomed to experiment elaborately upon the hearts 
 of animals, and have learned that they are really very hardy. 
 Even the hearts of warm-blooded animals will withstand 
 much manipulation within the body, and may be removed 
 in toto and retain their activity for many hours or even days. 
 Notwithstanding this, it has not been easy to overcome the 
 feeling that the human heart must be left untouched. For 
 many centuries its wounds were regarded as necessarily 
 fatal, and it is only within a period of about fifteen years that 
 surgeons have come to realize that this vital organ is not 
 outside their legitimate province. "The road to the heart," 
 says a graphic writer, " is only two or three centimeters in 
 length in a direct line, but it has taken surgery nearly twenty- 
 four hundred years to travel it." It should be added that 
 the route has finally been pointed out through animal 
 
144 SCIENTIFIC FEATURES OP MODERN MEDICINE 
 
 experimentation. Exposure of the heart in man is a com- 
 paratively simple procedure, which does not interfere with 
 its action and does not necessarily involve the opening of the 
 pleural cavities. Once exposed, the heart can safely be 
 handled, turned about for examination on all sides, and even 
 be lifted out of its nest. Wounds of the heart can thus be 
 definitely located, and are now sewed up, as are wounds in 
 other and less vital organs. Unless bacterial infection oc- 
 curs, or the loss of blood or the shock is too great, the propor- 
 tion of ultimate recoveries is considerable. Foreign bodies, 
 such as needles, knife-blades, and bullets, have been successfully 
 removed from the heart. But all such operations are merely 
 the beginning. Investigators are now experimenting on 
 animals with some degree of success in the endeavor to devise 
 methods by which more intricate pathological conditions, 
 such as the abnormalities of cardiac valves, the heart's cav- 
 ities, and blood-vessels can be corrected. These methods 
 frequently require the temporary cessation of the flow of 
 blood through the heart. One limitation to protracted 
 operations arises from the fact that if the circulation of the 
 blood be thus interrupted for more than four or five minutes, 
 serious and permanent degenerative changes occur in the 
 brain. Nevertheless, as knowledge increases, we may con- 
 fidently look forward to a considerable extension of cardiac 
 surgery. 
 
 One of the striking instances of the many protective adap- 
 tations with which the body is provided is afforded by the 
 bony cranium covering the brain. The bones comprising 
 the body of the skull are not only arched — the best mechani- 
 cal device for resisting external pressure — but are extremely 
 hard. The brain, which is essential to the maintenance of 
 an orderly life, is unusually well guarded against injury 
 
FEATURES OF MODERN SURGERY 145 
 
 from without. Nevertheless, it is not wholly free from 
 disorganizing agencies. The most resistant of arches may 
 yield and the hardest of bones may be fractured, and thus 
 the brain within may be made to suffer from direct injury 
 to its tissues, from the presence of foreign objects such as 
 bullets, from hemorrhages, or from pressure of broken bones 
 or escaped blood. So, too, infective bacteria may enter through 
 external wounds or by the way of the blood or the lymph, 
 and set up abscesses or inflammations. And lastly tumors of 
 every variety may develop withiii the brain substance. In 
 many of these cases operative relief is demanded, and here 
 scientific surgery has achieved some of its most brilliant re- 
 sults. The opening of the skull cavity by trephining is the 
 first step in the operation. Curiously enough trephining was 
 practiced in prehistoric times, as is shown in ancient skulls. 
 This must have been done with stone instruments, and 
 probably for both injuries and brain diseases. At times it 
 was doubtless associated with the theory that diseases are 
 due to demons which departed through the hole in the skull. 
 In the days of Hippocrates trephining was well known. One 
 hesitates to think of the slight success of such a heroic opera- 
 tion when performed with primitive means. In these aseptic 
 days it has been greatly perfected. It is a quick, simple, and 
 reasonably safe procedure to cut through the scalp and with 
 the circular trephine to saw from the skull a button of bone, 
 thus exposing to view the membranes of the brain and beyond 
 them the brain itself. If a larger field is required, a larger 
 piece of the bone covering is removed, care being taken to 
 preserve it for returning to its place at the end of the opera- 
 tion. Perhaps the most striking use to which this method is 
 now put is in the removal of brain tumors. For the exact lo- 
 cation of such foreign growths a knowledge of the physiology 
 
146 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 of the brain is necessary. Since the pioneer work of the in- 
 genious German physiologists, Fritsch and Hitzig, in 1871, 
 it has come to be known that the body nerves are connected 
 with localized groups of nerve-cells within the brain, each 
 group constituting a center for a particular part of the body. 
 Thus the eyes are represented in the brain by certain centers, 
 the ears by others, the muscles of the fingers, of the arms, of 
 the vocal organs, by still others, and so on throughout the 
 organism. If the nerve-cells in one of the centers be de- 
 stroyed, the activity of both the center and its corresponding 
 bodily organ ceases. If the center or its outgoing nerves be 
 unduly pressed upon, the tissues may either be stimulated 
 to an activity that is greater than normal, or, on the other 
 hand, may cease to act. In either case the activity of the 
 bodily organ keeps pace. Thus, one of the causes of blindness 
 may be destruction of, or pressure upon, the brain center of 
 sight; and one of the causes of the paralysis of the arm may 
 be destruction of, or pressure upon, the center that controls 
 the arm's movements. On the other hand, pressure upon a 
 sensory center may, through undue stimulation, cause unusual 
 sensations, or upon a motor center an abnormally prolonged 
 contraction or spasm of the muscles involved. * Such de- 
 struction of or pressure upon the parts of the brain may be 
 due to cerebral tumors, among the important symptoms of 
 which are the affected bodily movements and sensations. 
 By a careful observation and analysis of these, the surgeon 
 may be guided to the source of the trouble in the brain, and 
 may then remove the pathological growth, thus removing its 
 manifestations. If the substance of the brain center has been 
 actually destroyed by the tumor, or is so involved in it that 
 the removal of the one necessitates removal of the other, other 
 portions of the brain may often apparently take on the lost 
 
FEATURES OF MODERN SURGERY 147 
 
 function, and the bodily organ may thus be restored to normal 
 activity. Brain surgery has invaded the field of the long 
 mysterious disease known as epilepsy, which is manifested 
 by distressing bodily convulsions, or " fits." While the remote 
 cause of the epileptic condition is complex and unknown, there 
 is no doubt that the convulsive attacks result from excessive 
 activity of that portion of the cerebral cortex which controls 
 the body's movements. It is even possible to produce ex- 
 perimentally in animals a convulsion like that of epilepsy, 
 by exposing the motor area of the brain and stimulating it by 
 an electric current. In many cases of epilepsy there exists 
 a lesion of this motor region due to injury or disease. An 
 early surgical operation, which removes the irritating agent, 
 has afforded benefit in a considerable number of cases. 
 
 The work of the surgeon is not confined to the correction of 
 deformities, the repair of wounds, and the removal of tissue. 
 He frequently finds it necessary to supply deficiencies. The 
 earliest known instance of this is the transfusion of blood. 
 In the early years it was a favorite dream that through the 
 replacement of blood, one might cure diseases, invigorate the 
 enfeebled, and overcome moral obliquity; and in the latter 
 half of the seventeenth century blood transfusion from 
 animals to men for healing purposes began to be practised in 
 Europe. From that time for two himdred years it had its 
 enthusiastic advocates, but its all too frequent failures pre- 
 vented its becoming universal. The objection to the use of 
 blood from an animal that is far removed from man in the 
 zoological scale is owing to the fact that, on being introduced 
 into the human vessels and mingled with human blood, the 
 foreign, and to some extent the native, corpuscles are promptly 
 destroyed, and thus the benefits of the operation are nullified. 
 This destruction of alien corpuscles is but one instance of the 
 
148 SCIENTIFIC FBATUEES OF MODERN MEDICINE 
 
 defensive power of the body against foreign substances — 
 a power which here might appear to be acting contrary to the 
 body's own interests, and which would perhaps have been 
 ordered differently by us, if we, instead of nature, had had 
 the body's fashioning. However that may be, the human 
 body seems to be intolerant of any but human blood. This 
 fact has led to the frequent practice, in cases of need, of in- 
 troducing into the veins a solution of common salt. This is 
 often distinctly beneficial, especially when there has been 
 great hemorrhage. But the ideal circulating liquid is healthy 
 human blood, and within the last decade methods have been 
 perfected by which its transfusion can be safely effected. 
 A preliminary test with a few drops of blood should be made 
 of the compatibility of the blood of the individual who is to 
 become the donor with that of the recipient, in order to be 
 sure that the mixture will not result in a destruction of cor- 
 puscles. The operation consists in exposing and opening an 
 artery or a vein of the donor, frequently the radial artery of 
 the forearm, and uniting it to a vein of the patient by the 
 delicate stitching together of their coats, by an intervening 
 glass or metal tube, or by some other method that avoids 
 clotting. The blood, pumped by the donor's heart, is then 
 allowed to flow slowly to the recipient until a suitable quantity 
 has passed. The loss to a healthy vigorous person of a 
 considerable quantity of blood entails no serious consequences, 
 and it can be replaced within four or five days, while, except 
 in a few cases, that which is transfused finds in the recipient's 
 body a congenial home and proceeds to perform its customary 
 duties. Some of you will recall the striking case of two years 
 ago in this city, when the infant daughter of a physician was 
 saved from death by the process of transfusion. The baby 
 of four days suffered from the disease called hemophilia, 
 
FEATURES OF MODERN SURGERY 149 
 
 which is characterized by a constant oozing of blood from 
 the capillaries of the body. Every method of stopping the 
 hemorrhage that was known to medicine was tried in vain, 
 and the child at last reached a state of weakness that meant 
 its death within a few hours. As a last resort the father re- 
 solved to try the effect of transfusion. An artery in his own 
 arm was stitched to a delicate vein in his baby's leg, and 
 for ten minutes his blood flowed into her body. The fresh, 
 healthy, red fluid was retained, and proved to be of the right 
 composition. The child revived, and now owes her vigorous 
 life to the knowledge and the skill of the scientific surgeon. 
 Transfusion is now practised in a variety of conditions, such 
 as hemorrhage from various causes, shock, jaundice, as a 
 preliminary to a surgical operation that promises to prove 
 dangerous to the patient, and in poisoning by illuminating 
 gas, in which the blood, thoroughly saturated with the carbon 
 monoxide of the gas, is unable to take up oxygen. 
 
 A second instance of the transplantation of deficient ma- 
 terial is that of skin grafting, which has now been performed 
 very successfully for twenty-five years. Where, because of 
 disease, surgical operations, or accidents, parts of the body 
 have become denuded of their skin, it is possible to replace it. 
 One of several methods consists in shaving thin ribbons of the 
 superficial layers of healthy skin from a smooth area, such as 
 the inside of the thigh, either of the individual himself, or of 
 another donor. These ribbons consist of the epidermis and 
 a portion of the dermis, and may be five or six inches in 
 length and one and one half inches in width. They are care- 
 fully spread over the denuded surface, where they soon be- 
 come firmly adherent; blood vessels penetrate their lower 
 layers; the growth of cells begins; and within a few days a 
 layer of fresh tissue has made its appearance. This gradually 
 
150 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 increases in thickness, and in time the new skin assimilates 
 itself to the old. A patch of negro skin grafted upon a 
 white person becomes white ; white skin on a negro becomes 
 black. 
 
 A new era in reconstructive surgery seems likely to be 
 inaugurated through experimentation that is now being car- 
 ried on in the transplantation of whole organs. This work is 
 being performed on animals, but its growing success seems to 
 point the way to its ultimate extension to human beings. A 
 number of experimenters in various parts of the world are 
 engaged in it, and notable results have been obtained in this 
 city by Carrell, of the Rockefeller Institute for Medical 
 Research. It has been found possible, for example, to remove 
 from one animal a segment of an artery, even the aorta, the 
 largest artery of the body, and replace it by a similar piece 
 of artery taken from another animal. The transplantation 
 is successful even when the piece has been kept in the cold 
 for several weeks. A piece of artery from an animal of a 
 different species has even been employed. Thus successful 
 transplantations of arteries have occurred from the rabbit, 
 the cat, and even from man to the dog, and from the dog to 
 the cat. But, so far as I am aware, the experiment has not 
 yet been tried of transplanting from a lower animal to man. 
 Segments of veins have been used to replace segments of 
 arteries. In this case an interesting transformation in 
 structure takes place. The piece of vein in its new position 
 is subjected to a hitherto unwonted pressure from the blood, 
 but proves itself equal to the emergency. Instead of yielding, 
 the connective tissue in the thin wall grows and causes a 
 marked thickening and strengthening of the vessel, and thus 
 the new piece adapts itself to its elevated arterial dignity. 
 The future application of such facts to human surgery may 
 
FEATURES OP MODERN SURGERY 151 
 
 possibly be made in a variety of defective arterial conditions. 
 If, for example, the wall of an artery becomes weak in a 
 particular spot, a bulging outward may occur, constituting 
 an aneurism. This may greatly increase in size and ulti- 
 mately burst, causing a fatal hemorrhage. The new experi- 
 mental work indicates the possibility of removing such a 
 section of artery and replacing it with a healthy piece which 
 had previously been obtained from the body of a man killed 
 by accident. It is not yet known whether the artery of a 
 lower animal can be so employed. 
 
 Successful transplantations of thyroids, parathyroids, ova- 
 ries, spleens, and kidneys have been performed in animals. 
 Carrell has transplanted from one cat to another, in a single 
 mass, the two kidneys, their arteries and veins, with the ad- 
 joining parts of the aorta and the vena cava, the nerves and 
 the nervous ganglia of the kidneys, the entire ureters, and the 
 part of the wall of the urinary bladder through which the 
 ureters enter. The organs attached themselves to their 
 • host's body, and performed their functions well, although death 
 from unknown causes occurred after five weeks. The partial 
 success of such a complex operation is most encouraging. 
 Carrell has also succeeded in transplanting the entire leg below 
 the knee from one fox terrier to another. One leg of one dog 
 was carefully amputated, its blood was washed from its 
 vessels by a suitable solution of inorganic salts, and the leg 
 was laid aside. The corresponding leg of the second dog was 
 then amputated. The first leg was then fixed to the stump of 
 the second ; bones were joined to bones ; muscles to muscles ; 
 nerves to nerves ; arteries to arteries ; veins to veins ; and 
 skin to skin. The blood, which throughout the operation had 
 been prevented from escaping, was then admitted to the 
 newly acquired limb and was found to circulate. Normal 
 
152 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 healing was complete at the end of fifteen days. Most of 
 this work of transplantation has been performed within the 
 past five years. It is thus in its infancy, and it is impossible 
 to predict what its outcome will be. It opens, however, a 
 wide field of possibility and suggestiveness, and it is not 
 improbable that it will point the way to unique developments 
 in human surgery. 
 
 In the preceding lecture I have referred to the recent 
 achievements in the growth of timaors outside the body.^ By 
 a similar method other tissues may be made to grow. Harri- 
 son, of Yale University, first demonstrated the growth of 
 long nerve-fibers from nervous tissue taken from an embryo 
 frog. The method has now been ejctended at the Rocke- 
 feller Institute under Carrell and Burrows to other tissues of 
 young chicks and both young and adult dogs and cats. • As 
 with tumors, bits of normal tissue are placed on glass slides 
 in the clotted plasma of blood, the preparations are then sealed 
 and placed in a warm chamber, and, in the course of a few 
 hours, active cell growth and division begin along the edges 
 of the tissue and extend out into the plasma. The growth is 
 less rapid than with tumors under similar conditions. Nerve- 
 fibers, cartilage, connective tissue, bone, skin, cornea from 
 the eye, mucous membrane, and some of the tissues of the 
 spleen, thyroid, and suprarenal glands, pancreas, and kidney 
 have thus been cultivated successfully. Endeavors are 
 being made to discover the manifold conditions imder which 
 such growth occurs, and influences that will accelerate and 
 retard it. It is not possible at present to foretell how far 
 this kind of investigation will carry us. One practical result 
 may be the discovery of means by which the heahng of wounds, 
 which is now left largely to nature, may be greatly acceler- 
 
 ,» See p. 1X5. 
 
FEATURES OF MODERN SURGERY 153 
 
 ated. In the moods of our greatest optimism we may be 
 permitted to dream of far greater and far more wondrous 
 achievements. 
 
 Remarkable as has been the advance of surgery in recent 
 years, there is no reason to beheve that the end is yet in 
 sight. Surgery is no longer merely an art of skilful cutting 
 and sewing ; it has risen to the higher level of a science. 
 
VIII 
 
 THE e6lE of experiment IN MEDICINE. THE PUBLIC AND 
 THE MEDICAL PROFESSION 
 
 Our review of some of the features of modem medicine 
 has, I trust, made it evident that within the past century, 
 and largely within half that period, medical science and art 
 have advanced with a speed incomparably greater than at 
 any previous time. There has indeed been a second veri- 
 table renaissance. Instead of proceeding in a circle, as in 
 Bacon's time, the advance has been in all directions outward 
 into the unknown from the great mass of that which was al-. 
 ready known. The path of science is always devious. Sci- 
 ence essays this way and that, and rarely reaches its goal 
 over the course of a straight line. But the path of medical 
 science was never straighter than it has been, during this 
 modern epoch. The cause of this unprecedented progress is 
 as complex as is that of any other movement of civilized man; 
 but the most powerful single factor is undoubtedly experi- 
 ment. Ancient medicine is characterized preeminently by 
 philosophical speculation and empiricism ; modern medicine 
 by experimentation. The ancient physician was content to 
 observe phenomena as they existed under their natural con- 
 ditions, to interpret them in accordance with a philosophical 
 system, and to treat disease in the light of what his system 
 and past experience had taught him. The modem physician 
 does not rely on a philosophical system. Like his fore- 
 runner, however, he, too, observes phenomena \mder their 
 natural conditions; but he goes further than this and alters 
 
 154 
 
EXPERIMENT IN MEDICINE 155 
 
 the conditions, and thus he obtains an alteration of the 
 phenomena and a new standpoint from which to view them. 
 He may apply to the cure of disease past experience, it is 
 true, but it is past experience that has been put to the test of 
 modem experiment. Moreover, by the aid of further ex- 
 periment he pushes out into the unknown, sees disease from 
 unusual standpoints, and devises new and hitherto unsus- 
 pected methods of dealing with it. If he forms a working 
 hypothesis, it, too, hsia to be submitted to experimentation, 
 for men of medicine have little patience with a new idea that 
 has no experimental evidence in its favor. 
 
 But what do we mean by experimentation? We obtain 
 our knowledge of the phenomena of nature from observation 
 by means of our special senses, which modern physiology 
 tells us are more in number than the traditional five. Through 
 the gateways of these six or seven senses we may look out 
 and see what nature is doing. But the more we have learned 
 by such simple observation, the more eager to learn we have 
 become, and the more impatient of always waiting for na- 
 ture to present her phenomena in her own chosen way. We 
 have learned, moreover, that nature is not immutable, but 
 that we can change the conditions under which she manifests 
 herself. Thus, if nature shows us an object cold, we can 
 make it warm ; if it is dry, we can moisten it ; if it contains 
 certain chemical constituents, we can replace them by others ; 
 if it is a Uving object at rest, we can stimulate it to activity ; 
 if its processes are complex, we can resolve them into simpler 
 ones. Thus we can voluntarily control nature's phenomena 
 in a great variety of ways ; we can control their beginning, 
 their progress, and their ending; and in this way we can 
 make them more accessible to observation. This is the 
 essence of experimentation. It is the voluntary control or 
 
156 SCIENTIFIC FEATURES OF. MODERN MEDICINE 
 
 modification of natural phenomena. It is an artificial aid 
 to simple observation. By means of it we can penetrate 
 more rapidly and more deeply into nature's secrets than it 
 would ever be possible for us to go unaided. 
 
 Some of the ancients performed experiments. Archimedes 
 conceived the greatest of them all: "Give me where I may 
 stand," he said, "and I will move the earth." It is doubtless 
 well for us of a later generation that his condition was im- 
 possible of fulfilment. But Galen was less ambitious. He 
 tied an artery of a living animal in two places, and on open- 
 ing it between the ligatures found that it contained blood, 
 and thus at once by a simple device he disproved the theory 
 of all the centuries that had preceded him, that the arteries 
 were air-tubes. Harvey, in Charles the Second's time, was 
 fertile in experiments to demonstrate that the blood circu- 
 lates. A century and a half later Haller cut the nerve con- 
 necting the spinal cord and a muscle, and demonstrated that 
 the muscle is capable of contraction without receiving the 
 hypothetical animal spirits from the brain. But experiment 
 as the all-important method of acquiring knowledge did not 
 permeate science imtil the nineteenth century, until men 
 realized how inadequate for advance were both philosophical 
 systems and unaided observation. One by one, various 
 branches of medical science have come to realize that the 
 experimental method is indispensable to their progress. 
 Physiology was the first to appreciate this. Then followed 
 pharmacology, pathology, and bacteriology; and lastly 
 anatomy has come to see that a complete knowledge of struc- 
 ture can be obtained only through a knowledge, acquired 
 experimentally, of the mechanism of growth. The achieve- 
 ments of the experimental method are already extraordinary, 
 and its future possibilities seem almost inexhaustible. 
 
EXPERIMENT IN MEDICINE 157 
 
 Let me illustrate how this method is applied to-day to the 
 study of a single organ, the heart of a higher animal. 
 A knowledge of the structure of this organ should first be 
 obtained by observation of the dead heart, dissecting it, and 
 examining its tissues by the aid of the microscope. A com- 
 parative study of the hearts of a series of animals is valuable. 
 It is desirable also to know how the heart has developed from 
 its earUest embryonic appearance to its adult stage. It is 
 obvious that without some preliminary knowledge of the 
 way in which the heart acts, it is difficult to learn much of its 
 physiology while it is still enclosed within the chest. One 
 of the first experimental procedures is, therefore, to make it 
 more accessible. Happily anaesthetics have simplified this. 
 An animal, such as a dog, a cat, or a rabbit, is anaesthetized 
 by means of one of the accepted general anaesthetics, ether 
 or chloroform. The heart is not exposed at once, but the 
 trachea in the neck is first opened and one end of a tube of 
 glass or metal is inserted into the opening and fastened in 
 place. Through this tube the vapor of the anaesthetic is 
 readily administered throughout the subsequent course of the 
 experiment, of which the animal knows nothing. The 
 heart can then be exposed to view by cutting away the front 
 wall of the chest and opening the pericardium. Because 
 of the free opening of the chest cavity, the lungs collapse, and 
 natural respiration becomes impossible. Through the tube 
 in the trachea, however, a current of air can be pumped 
 intermittently into the lungs, and this artificial respiration 
 must be maintained thereafter. The heart can then be 
 quietly and leisurely observed in activity. No one, however 
 unimpressionable, can watch a living, beating heart lying be- 
 fore him, with its parts contracting and relaxing in perfect 
 rhythm, alternately emptying and filling, hardening and soft- 
 
158 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 ening, paling and blushing — no one, I think, can watch such 
 an object without a profound feeling of admiration, on the one 
 hand for its wonderful mechanism, and on the other for what 
 scientific medicine has been able to accomplish in devising 
 methods for its understanding. But direct observation of 
 the heart in situ is only the beginning. Levers with writing 
 points can be attached to its various parts, and their move- 
 ments can be graphically recorded on moving paper in the 
 form of waves, which reveal the force and the rate of the 
 beats and any alterations in force and rate that may chance, 
 or be made artificially, to occur. The heart can be con- 
 nected with a delicate galvanometer, which indicates the 
 electrical changes accompanying its beats. An artery can 
 be opened and connected with a manometer, which measures 
 and records the pressure within the artery and the pulse- 
 beats, and gives a clue to the amount of work that the 
 heart performs. The cavities of the heart can be connected 
 with similar manometers, and their dynamic conditions can 
 thus be revealed. The two kinds of nerves passing from the 
 brain to the heart can be artificially stimulated and their 
 actions can be observed and recorded — the one kind weak- 
 ens, slows, and can temporarily stop the beats; the other 
 strengthens and quickens them. The depressor nerve pass- 
 ing from the heart to the brain can be stimulated — it 
 depresses the activity of the vasomotor center in the brain, 
 and thus reflexly dilates the body's arteries and diminishes 
 the arterial resistance against which the heart has to contend. 
 The two kinds of nerves directly supplying the arteries can 
 hkewise be stimulated, the one constricting, the other dilating 
 them, and thus the effects of varying blood-pressures can 
 be recorded and studied. By stopping respiration tempo- 
 rarily the action of varying degrees of asphyxia can be stud- 
 
EXPERIMENT IN MEDICINE 159 
 
 ied. By compaxing the chemical composition of the incom- 
 ing with that of the outgoing blood, data can be obtained 
 concerning the effect of the heart's action on the blood, and 
 the metabolism of the heart muscle. Metabolic products, 
 foods, drugs, poisons, and bacterial toxins can be injected into 
 the blood, and their varying actions on heart and arteries can 
 be observed. The blood can be removed and replaced by 
 blood of a different composition, or by an artificial circulating 
 liquid, and thus the action of heat, cold, and various chemical 
 substances can be studied. The action of the heart valves 
 can be interfered with, as happens in various diseases. Other 
 diseased conditions can be produced and studied with an 
 exactness such as never can be hoped for in the intact body. 
 The heart can be wholly removed from the body, can be fed 
 with a nutritive Uquid and be kept beating for hours under 
 artificial and easily controlled conditions, which make 
 possible the exact observation and record of many influences, 
 normal and pathological. Parts of the heart can be removed 
 and studied in action, an experiment which simplifies the 
 investigation of certain problems, such as the nature of the 
 heart beats. And so, in a thousand ways, undreamed of 
 by our predecessors and often incomprehensible to the 
 layman, we have acquired and are still acquiring knowledge 
 of the normal and pathological phenomena of this intricate 
 organ. Yet this is but a small part of the tale that may be 
 told. There is no organ in the body, physical or chemical, 
 to which the experimental method is not applicable, and 
 from which secrets may not be wrung by its intelligent use. 
 Obviously the experimental method requires laboratories 
 in which the work may be carried on, and within seventy-five 
 years, beginning with Purkinje's physiological laboratory, 
 which was established at Breslau in 1839, such institutions 
 
160 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 have sprung up throughout the world in all of the medical 
 sciences. No other field of scientific work is now more active. 
 Of great importance also are the innumerable clinics and 
 hospitals that have been established. The latter half of 
 the nineteenth century was especially rich in the founding 
 of such institutions and the improving of those already exist- 
 ing. Clinics and hospitals are necessary adjuncts to the 
 laboratories, since they offer opportunities for the applica- 
 tion to human beings of the results of laboratory research, 
 and, furthermore, serve as laboratories for such experimental 
 work as can legitimately be carried out on men. 
 
 Of the innmnerable varieties of experimental work now 
 undertaken, it is obvious that a certain proportion cannot 
 be performed upon human beings. No one is morally justi- 
 fied in removing from the body of a fellow-being a vital part, 
 or endangering his life or well-being in any way for the 
 purpose of experiment. For such work animals lower than 
 man are employed, and these include a considerable variety 
 of species, ranging all the way from the microscopic protozoa 
 to the higher mammalia. The use of anaesthetics, as in 
 human surgery, has quite altered the aspect of such work, and 
 allowed a great extension of it. Animals are now employed 
 for many varieties of physiological investigation, for determin- 
 ing the physiological actions of drugs, foods, and other chemi- 
 cal substances, for standardizing drugs, for devising new sur- 
 gical operations, for the preparation of serums, for diagnosing 
 certain diseases, for studying disease, and in teaching the 
 elements of medical science to students. Many diseases can 
 be experimentally induced in animals, and thus their causes, 
 treatment, and cure can be more rapidly and effectively inves- 
 tigated than imder the limitations of investigation in man. 
 This is strikingly true of the infectious diseases. From a 
 
EXPERIMENT IN MEDICINE 161 
 
 study of the conditions in animals one can pass to the ob- 
 servation of normal and diseased states in man with a host 
 of preliminary questions already answered, and with a clear 
 appreciation of how to proceed and what to do in order to 
 understand and alleviate human conditions. The use of 
 animals for experimental purposes has, in fact, been one of 
 the most important factors in the rapid and efficient advance 
 of scientific medicine. 
 
 In view of the great extension of the commendable hu- 
 mane movement of the past half century it is perhaps not 
 surprising that opposition to the use of animals for scientific 
 purposes has appeared in certain quarters and is hotly main- 
 tained by a few individuals. This opposition sometimes wil- 
 fxilly denies the value of animal experimentation in scientific 
 progress; it sometimes assumes the extreme and ethically 
 indefensible attitude of denying the right of man to use ani- 
 mals at all as experimental objects ; and it has as its practical 
 aim the establishment of legal restrictions against the prac- 
 tice. These vary in degree from slight limitations to total 
 prohibition. The antivivisection view is psychologically of 
 great interest. It rests on a low intellectual and ethical level, 
 and exhibits in an elemental simplicity the quaUties and the 
 power of emotion. Its abnormal sympathy for animals 
 blinds its possessor to a normal sympathy for hmnan beings. 
 It assumes the present existence of cruelty in laboratories. 
 As evidence of such cruelty it either recites for the thou- 
 sandth time one of a half dozen classic instances of experi- 
 mental procedures that date from an early period before the 
 use of anaesthetics became general, or it misinterprets or 
 misquotes instances of modem procedure. I have been at 
 considerable trouble to make a detailed examii^ation of its 
 literature, searching for the origin and the justification 
 
 M 
 
162 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 of its oft-repeated phrases and its specific charges of cruelty, 
 and I have found the hterature wholly unreliable. Its mis- 
 leading character has indeed often been pointed out, and has 
 now, I think, became generally recognized. It should never 
 be resorted to as a source of correct information regarding 
 the modern laboratory. Many antivivisectionists are fre- 
 quently sincere, and undoubtedly undergo great mental an- 
 guish over the supposed unwarranted sufferings of animals. 
 But they are fighting a monster that does not exist. Effec- 
 tive anaesthetics are as universal in operations upon experi- 
 mental animals as in those upon man. At the conclusion of 
 an operation, if the existence of the animal's life is no longer 
 required, he is painlessly killed ; if it is required, he is humanely 
 cared for. If a disease is produced within his body, there is 
 every reason to believe that because of his low mental or- 
 ganization he suffers far less than would a human patient 
 under similar conditions. Opposition to animal experimenta- 
 tion has succeeded in Great Britain in placing the leaders of 
 scientific medicine under severely restrictive laws and a con- 
 stant suspicion which is degrading both to them and to their 
 fellowmen and hostile to healthful scientific progress. The 
 force of this opposition is now happily diminishing among the 
 more intellectual classes in England. In the United States 
 the antivivisection movement has never secured any con- 
 siderable following, and no legislature has yet yielded to its 
 fanatical demands. Nor is this to be expected. Scientific 
 research has already brilliantly justified its claim that only 
 through freedom from petty restrictions can it advance. 
 Biological and medical research has demonstrated that it is 
 humanitarian in the highest degree, both in method and in 
 achievement. Men of medicine have been practically a unit 
 in resisting opposition to such research, and this resistance 
 
EXPERIMENT IN MEDICINE 163 
 
 should be stoutly maintained if our present rate of progress 
 in scientific medicine is to continue. In the interest of this 
 progress and of a broad humanitarianism, not only men of 
 medicine, but the public outside of the medical circle, should 
 jealously guard the freedom of scientific experimentation. 
 
 The increasing breadth of investigation in the medical 
 sciences is coupled with a broadening of those who partake 
 in it, and has enabled them to realize that theirs is a part 
 of a comprehensive biology. In discovering the laws of 
 health and disease they are not simply saving human be- 
 ings from death, but are contributing to the larger field of 
 the science of Uf e. Much investigation in medical laboratories 
 hence seems at first sight far removed from medicine. Ehr- 
 lich injected dye-stuffs into rabbits, and observed what 
 tissues were most deeply colored. There might seem no 
 possible relation between this strange proceeding and the 
 cure of disease, yet it led him to appreciate clearly that 
 specific drugs possess precise affinities for specific cells. 
 Thence he was led through a long series of experiments to the 
 discovery of that compound of arsenic, a single dose of which 
 may seek out with unerring exactitude and destroy every 
 Treponema in a syphilitic body, and thus put an end to a 
 loathsome disease without injuring the tissues in which it 
 thrives. By a similar course he seems to have found an 
 equally effective and safe poison for the germs of sleeping 
 sickness. 
 
 I know of no more striking instance of an apparently 
 purely scientific discovery yielding large practical benefits 
 than that of Galvani and his frogs. Galvani was a 
 physician living in the old Italian city of Bologna, and a 
 professor in its ancient university. The electrical machine 
 was already long known, and Franklin had performed his 
 
164 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 experiments on atmospheric electricity. Galvani became 
 interested in the apparently trivial phenomenon of the twitch- 
 ing of the muscles of frogs' legs. He performed many and 
 diverse experiments to ascertain the source of the stimula- 
 tion. He proved that, contrary to expectation, the electrical 
 machine was not necessary, nor was atmospheric electricity. 
 But when he allowed a circuit to be completed through the 
 frog's muscles, a brass hook attached to its spinal cord, and 
 an iron trellis of his house, he always obtained a vigorous 
 contraction of the muscles. This simple and seemingly 
 childish experiment has brought in its train momentous re- 
 sults. In the first place, it was the beginning of a knowledge 
 of animal electricity, which we are using daily for the inter- 
 pretation of physiological phenomena, and, in some degree, 
 for the diagnosis of disease. But, far greater than this, the 
 use of two metals in Galvani's experiments suggested to Volta 
 that in their dissimilarity lay the source of the electricity. 
 He thereupon proceeded to experiment with metals, and 
 evolved the voltaic pile, the first apparatus to generate a 
 continuous electric current and make a study of its powers 
 possible. The galvanic battery soon became a reality; 
 experiment succeeded experiment ; and to-day we have the 
 electric light and the thousand uses to which electricity is 
 put, direct descendants of an observation made by a physician 
 in order to understand why frogs' legs twitch. The city of 
 Bologna is properly proud of its citizen's achievements, 
 and has not only inscribed his house, but has erected in one 
 of its pubhc squares a statue of Galvani, holding in his hands 
 a tablet bearing an image of his preparation of frogs' legs. 
 Discoveries like his — and such instances are numerous — 
 show us that we can ill afford to decry scientific experiments 
 that do not have an immediately obvious, practical applica- 
 
EXPERIMENT IN MEDICINE 165 
 
 tion. Of two men of science we sometimes hear the practical 
 man praised as the man who does things, while he who spends 
 his time investigating theories is looked upon as a dreaming 
 idealist, whose discoveries may be interesting enough, but 
 are of little use. This attitude of mind is even found within 
 the medical profession itself, but its short-sightedness has been 
 demonstrated so often that it is less common there now 
 than formerly. It is one of the cardinal features of the anti- 
 vivisection idea. The sooner we free ourselves from such a 
 narrow conception of scientific endeavor, and the more we 
 encourage the freedom of research, the sooner will scientific 
 medicine arrive at its goal. The success of the practical 
 man is largely due to the fact that he applies the principles 
 which the idealist has discovered. 
 
 In the first lecture of the present course I spoke of the popu- 
 lar distrust of both the medical profession and its efficiency 
 in curing disease. Such distrust has always existed. The 
 literature of all ages is full of gibes regarding things medical. 
 A chilly Greek epigram runs thus: "Marcus, the doctor, 
 called yesterday on the marble Zeus; though marble, and 
 though Zeus, his funeral is to-day;" and a Latin proverb 
 affirms that there is "more of danger from the physician than 
 from the disease." Montaigne, who suffered from a common 
 ancient malady, which the medicine of his time found hard 
 to cure, at last became very tolerant of his trouble and his 
 pain, but not of his inefficient sixteenth-century physicians. 
 In his essays he has a famous chapter in which he expresses 
 himself freely concerning them. "Mine ancestors," he says, 
 "by some secret instinct and naturall inclination have ever 
 loathed al maner of Physicke." "My father lived three score 
 and fourteen yeares ; my grandfather three score and nine ; 
 my great-grandfather very near four score, and never tasted 
 
166 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 or tooke any kind of Physicke." "The very sight of drugs 
 bred a kinde of horror in my father. ... I see no kinde of 
 men so soone sicke, nor so late cured, as those who are under 
 the jurisdiction of Physicke. ... A Lacedemonian being 
 asked, what had made him live so long in health, answered 
 'The ignorance of physicke !' . . . A physition boasted 
 unto Nicocles, that his Arte was of exceeding great authority. 
 It is true (quoth Nicocles) for it may kill so many people 
 without feare of punishment by Law." Yet it was not 
 against physicians that Montaigne bore malice. "As for 
 me I honour Physitions, not according to the common re- 
 ceiv'd rule, for necessitie sake . . . but rather for the love I 
 bear unto themselves; having seene some, and knowne 
 diverse honest men amongst them, and worthy all love and 
 esteeme. It is not them I blame, but their Arte." A hun- 
 dred years later that master of delicious comedy, Moli^re, 
 ridiculed well the degenerate medicine of his time. It is 
 related that the king once asked him how he got along with 
 his physician, and he rephed: "Sire, we talk together; he 
 prescribes remedies for me ; I do not take them ; and I get 
 well." Sganarelle, who was made a doctor in spite of him- 
 self, soon found it a profitable undertaking : " I think I had 
 better stick to physic all my life. I find it the best of trades ; 
 for, whether we are right or wrong, we are paid equally well. 
 We are never responsible for the bad work, and we cut away 
 as we please in the stuff we work on. A shoemaker in making 
 shoes can't spoil a scrap of leather without having to pay for 
 it, but we can spoil a man without paying one farthing for 
 the damage done. The blunders are not ours, and the fault 
 is always that of the dead man. In short, the best part of 
 this profession is, that there exists among the dead an honesty, 
 a discretion that nothing can surpass ; and never as yet has 
 
EXPERIMENT IN MEDICINE 167 
 
 one been known to complain of the doctor who had killed 
 him." Now the art of the twentieth-century doctor is a very 
 different affair from that of his forerunner of four hundred or 
 three hundred years ago, yet Montaigne's and MoliSre's 
 commentaries, as do those of the ancients, have a curiously 
 modern sound ; so much so indeed that one cannot refrain from 
 thinking that much of the present distrust of the medical 
 profession had its rise in tradition. Traditional criticism 
 can always find sympathetic ears. It long ago became the 
 custom to deride the doctor. Montaigne and MoliSre in- 
 herited it, and so have the critics of to-day. 
 
 Next in order among the causes of the present distrust 
 of medicine I would place ignorance. And here, first and most 
 important of all, is the appalling ignorance which people 
 possess of their own bodies and their bodily processes. If 
 asked to locate his heart or his stomach, the average man would 
 probably place the one in the middle of his left chest cavity, 
 and the other in the middle of his abdomen. Of their func- 
 tions he would be chary of expressing an opinion, but he 
 knows that the heart is related in some way to the circula- 
 tion of the blood, and that the stomach receives food and 
 digests it, or at least attempts to digest it. He has less 
 knowledge of the purpose for which his liver exists, except 
 to make him "bilious" or to get "sluggish" or "torpid" or 
 "out of order." He is usually not aware of the fact that he 
 even possesses a pancreas, and when assured that such 
 an organ really exists, he is quite at a loss to know of what 
 possible use it can be to him. He has no clear idea of the 
 arrangement of the nerves in his body, nor of the way in 
 which they perform their tasks. He cannot analyze a reflex 
 action. The solar plexus to him is only a place in which to 
 bit his opponent. A supposedly intelligent lady, after 
 
168 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 listening to one of Huxley's lucid lectures on the brain, asked 
 him if he would kindly enlighten her about one point which 
 she had failed to grasp, namely : whether the cerebellum is 
 inside or outside the skull ? A vasomotor nerve would be a 
 poser for the average man, as would the tricuspid valve, 
 the thyroid gland, the pancreatic duct, lymph, trypsin, the 
 pylorus, and the mode of seeing and hearing, though he might 
 talk glibly of his "system," his "economy," his "constitu- 
 tion," and his "pores" — all of them echoes of a prehistoric 
 physiology. Of how to maintain his health he thinks he 
 knows much. He says that this food " agrees " and that food 
 "disagrees" with him; and with much feehng, but little 
 reason, he ascribes particular sensations to particular foods. 
 He remembers the identical draft which caused his present 
 " cold." He believes in exercise, but does not take it. But 
 if he has so little clear conception of what goes on within 
 himself normally, how does he behave when disease comes, 
 for of pathology he knows less than of physiology ? He feels 
 certain symptoms, but he does not understand their diag- 
 nostic significance. He knows not whether they are im- 
 portant or unimportant, or whether or not they demand a 
 doctor's knowledge. He trusts blindly to the hope that if he 
 neglects them they will pass away. If they persist, he diag- 
 noses his own disease and attempts to treat it. If at last he 
 is forced to appeal to the doctor, he learns that of the real 
 nature of his disease he knows practically nothing, except 
 what the doctor may tell him. Largely because of ignorance, 
 he shrinks from a surgical operation until the extreme condi- 
 tion has arrived. He will submit to the taking of innumer- 
 able drugs, but for what purpose they are prescribed, of the 
 physiological action of the components of a prescription, he 
 has no conception. And so, from the beginning to the end, 
 
EXPERIMENT IN MEDICINE 169 
 
 there is ignorance, crass ignorance, of the body, and what the 
 physician can do for it. 
 
 A third cause of distrust of medicine lies in the inability of 
 the physician to do certain things. "We all have had personal 
 experience of this. In considering it we should bear in mind 
 that the conmion soldier fighting in the ranks is never the 
 peer of his commanding officer. The great body of the 
 medical profession has not the scientific knowledge and skill 
 of its leaders, and we ought not to judge the powers of medi- 
 cine indiscriminately from the limitations of whoever may be 
 licensed to practise. Notwithstanding this, the best of medi- 
 cine is often powerless. I have already pointed out that 
 however skilful diagnosis has become, it often makes mistakes. 
 Disease is often a much more complex affair than its symptoms 
 indicate, and scientific medicine has still much to learn re- 
 garding the interpretation of symptoms. When we pass from 
 diagnosis to treatment, we find that " The best laid schemes 
 o' mice and men gang aft agley." Drugs that stimulate do 
 not always stimulate, and drugs that depress do not always 
 depress. This remedy and that do not keep their promises. 
 For a hundred times a course of treatment may succeed, .and 
 in the hundred and first time it fails. Unforeseen complica- 
 tions enter, and imknown conditions arise, and the patient 
 steadily grows worse. Moreover, while medicine has 
 achieved much, in every direction there are imsolved prob- 
 lems. The doctor can deal with diphtheria like magic, but 
 he has no antitoxin for a cold in the head, or an attack of 
 influenza. Rheumatism in his hands often thrives madly. 
 He can skilfully remove or can stay the progress of a cancer, 
 but a digestion that has given way after the accumulation 
 of the gastric indiscretions of years he cannot cure in a day. 
 A persistent high mortaUty from Bright's disease of the kid- 
 
170 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 neys and various maladies of the heart reveals the growing 
 need for their investigation. When this occasional impotence 
 of scientific medicine is disclosed in cases where one's own life 
 or the Uves of those near to one are at stake, it is perhaps not 
 to be wondered at that, with emotions strongly aroused, one 
 sometimes belittles the achievements that are already accom- 
 phshed. 
 
 But if from tradition, his own ignorance, the inability of 
 conventional medicine to do the impossible, or for any other 
 reason, the individual has come to distrust the medical 
 profession, what is he to do ? Shall he seek rehef in a medical 
 sect, in homeopathy or eclecticism, or in such an aberrant 
 school of heaUng as osteopathy ? Or shall he fly to one of 
 those several cults that offer a safe refuge to malcontents by 
 promises of cure through psychic agencies ? Shall he become 
 a Christian Scientist, or a follower of one of the many other 
 varieties of faith healing or of New Thought ? 
 
 It is interesting to watch the course of these protesting 
 iconoclastic movements. They present certain features in 
 common. Homeopathy with its elaborate dogma regarding 
 drugs, its principle of "similia simiUbus curantur," its "po- 
 tencies" and its "attenuations," arose in Germany a hundred 
 years ago, but has gained its chief following in America. It 
 has already passed its zenith, and is now declining. Its 
 twenty-two medical schools existing in this country in 1900 
 had decreased to fifteen in 1910, and its student body had 
 been diminished by one half. The best of homeopathy has 
 now assimilated itself to scientific medicine, and as a separate 
 body it will undoubtedly soon cease to be. Eclecticism 
 represents a feeble survival of an effete medical system, and 
 hardly deserves mention. 
 
 In osteopathy, on the other hand, we now have the oppor- 
 
EXPERIMENT IN MEDICINE 171 
 
 ttmity to observe the rise of such a system. Osteopathy is 
 an outgrowth from the primitive conditions prevailing on our 
 western frontier in the period preceding our Civil War, when 
 educated physicians were few, opportunities for rational 
 treatment were fewer, and boldness in assertion and action 
 counted far more than exact conformity to scientific truth. 
 The founder of osteopathy was one of the rude, itinerant 
 practical bone-setters, probably often clever in his attitude 
 toward the sick. Though unlettered, he was possessed of a 
 positive philosophy that found a sympathetic hearing in the 
 home of many an unlearned frontiersman, who would have 
 been ill at ease imder the ministrations of one trained in the 
 nice theories of academic medicine. Osteopathy was and still 
 is full of unfounded assertions regarding the normal func- 
 tioning of the bodily structures, and the nature and proper 
 methods of cure of disease, though of late years its more 
 enlightened practitioners appear to-be endeavoring to har- 
 monize its practices with certain accepted scientific prin- 
 ciples. It speaks much of "lesions," by which it means, not 
 the commonly accepted pathological idea of morbid changes, 
 but rather "any structural perversion which by pressure 
 produces or maintains functional disorder." Of all parts of 
 the body subject to lesions the "spine" is of fundamental 
 importance, and "it is only in occasional cases of disease 
 that no treatment is given to it." Treatment consists chiefly 
 in correcting the structural perversion by manipulation with 
 the hands, and thus removing the pressure on the function- 
 ally disordered organs or on nerves and blood vessels supply- 
 ing them. The osteopath serenely, with a single stroke of 
 the hand, waves away the facts of scientific pathology. Says 
 the prophet : 
 "I have concluded, after twenty-five years' close observa- 
 
172 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 tion and experimenting, that there is no such disease as fever, 
 flux, diphtheria, typhus, typhoid, lung-fever, or any other 
 fever classed under the common head of fever. Rheumatism, 
 sciatica, gout, colic, liver disease, nettle-rash, or croup, on to 
 the end of the list of diseases, do not exist as diseases. All 
 these, separate and combined, are only effects. The cause 
 can be found, and does exist, in the limited and excited action 
 of the nerves only, which control the fluids of parts or the 
 whole of the body." The cause of all diseases is "a partial 
 or complete failure of the nerves to properly conduct the 
 fluids of life." One can with diflBculty suppress a feeling 
 of admiration for the audacity with which time-honored 
 scientific facts and principles are thus put aside. Oste- 
 opathy undoubtedly effects cures, but so does the medicine 
 man of the savage tribe. 
 
 Of the value and hmitations of psychic agencies in the 
 treatment of disease I have already spoken. It remains, 
 however, to consider briefly some of those prominent sects 
 in which mental healing overshadows all else. Christian 
 Science, Uke osteopathy, had its rise in humble circumstances. 
 In Phineas Parker Quimby, a clockmaker of New England, 
 the germs of its philosophy seem to have originated; but 
 in the visionary mind of Mary Baker Eddy they came to full 
 fruition. Christian Science says that "Man is not matter, 
 he is not made up of brain, blood, bones, and other material 
 elements. . . . Man is idea. . . . Man is incapable of 
 sin, sickness, and death." "Health is not a condition of 
 matter, but of Mind." "What is termed disease does not 
 exist." "If the body is diseased, this is but one of the beliefs 
 of mortal mind." "We weep because others weep, we yawn 
 because they yawn, and we have smallpox because others have 
 it; but mortal mind, not matter, contains and carries the 
 
EXPERIMENT IN MEDICINE 173 
 
 infection." "All disease is cured by divine Mind." "You 
 say a boil is painful ; but that is impossible, for matter with- 
 out mind is not painful. The boil simply manifests, through 
 inflammation and swelling, a belief in pain, and this belief 
 is called a boil. Now administer mentally to your patient a 
 high attenuation of truth, and it will soon cure the boil." 
 "To reduce inflammation, dissolve a tumor, or cure organic 
 disease, I have found divine Truth more potent than all lower 
 remedies." "Decided types of acute disease are quite as 
 ready to yield to Truth as the less distinct type and chronic 
 form of disease. Truth handles the most malignant con- 
 tagion with perfect assurance." "If the case to be mentally 
 treated is consumption, take up the leading points included 
 (according to beUef) in this disease. Show that it is not 
 inherited; that inflammation, tubercles, haemorrhage, and 
 decomposition are beliefs, images of mortal thought superim- 
 posed upon the body ; that they are not the truth of man ; 
 that they should be treated as error and put out of thought. 
 Then these ills will disappear." There is a certain type of 
 mind that loves to play with thoughts like these. They 
 require no depth of intellect or logic. They merely skim the 
 surface of consciousness. It demands no great expenditure 
 of mental power to learn the essentials of this crude meta- 
 physics; and with that once mastered the whole field of 
 medical possibiUty is before one. 
 
 When we read the records of the many cures that are 
 claimed by Christian Science, we are impressed at first by 
 the inexactness of the diagnoses. Thus we read of patients 
 being ciu-ed of "a fever," "an internal disease," "an 
 internal complaint," "Hver complaint," and a long list of 
 "troubles," such as "heart trouble," "stomach and bowel 
 trouble," "abdominal trouble," "lung, liver, and kidney 
 
174 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 trouble," "neck trouble," "throat trouble," "nervous 
 and spinal trouble." With such uncertainty as to the 
 real nature of the diseases it is not strange that proof of 
 cures is difficult to obtain. Among many others, Cabot, 
 of Boston, has examined the evidence of a considerable 
 number of such "cures." "In my own personal researches 
 into Christian Science 'cures,'" he says, "I have never found 
 one in which there was any good evidence that cancer, con- 
 sumption, or any other organic disease had been arrested or 
 banished. The diagnosis was usually either made by the 
 patient himself or was an interpretation at second or third 
 hand of what a doctor was supposed to have said. As I 
 have followed up the reported cures of 'cancer' and other 
 malignant tumors, I have found either that they were not 
 tumors at all, or that they were assumed to be mahgnant 
 without any microscopic examination. In other words, the 
 diagnosis was never based upon any proper evidence. . . . 
 By a curious process of 'natural selection,' a patient suffering 
 from organic disease rarely consults a Christian Scientist, 
 just as he rarely consults an osteopath. Being ignorant of 
 diagnosis, the Christian Scientist is not aware of this fact, 
 and supposes that he is treating, not a selected group of cases 
 of functional disease, but all disease. This mistake is all 
 the more natural, because the Christian Scientist, with the 
 natural credulity of the half-educated, accepts the patient's 
 own diagnosis at its face value or trusts the hearsay report 
 of what some doctor is supposed to have said. ... It is 
 a striking fact that, as one listens to the recital of Christian 
 Science 'cures,' one hears little or nothing of the great com- 
 mon organic diseases, such as arterio-sclerosis, phthisis, 
 appendicitis — and still less of the common acute diseases, 
 such as pneumonia, malaria, apoplexy. Chronic nervous 
 
EXPERIMENT IN MEDICINE 175 
 
 (that is, mental) disease is the Christian Scientist's stock in 
 trade." 
 
 Cabot's judgment does not differ essentially from that of 
 others, and we must believe that as a therapeutic agent 
 Christian Science is to be classed with the various other 
 systems of mental healing, and is of very limited therapeutic 
 appHcation. Its ignorance of scientific medicine and its 
 unwise extension into unwarranted fields are undoubtedly 
 responsible for a vast amount of maltreatment of the sick 
 and of unnecessary suffering. Its material success is due 
 less to its merits as a system of healing than to other factors 
 which appeal to the credulous, and it is undoubtedly destined 
 to follow the course of its many vanished predecessors. 
 
 Supreme above all partisan healing sects and systems and 
 creeds stands the scientific medicine of to-day, the heir of all 
 that has preceded it since men began to heal. It asks itself 
 these questions : What is health ? What is disease ? How 
 may disease be prevented? How may the sick be cured? 
 Its business is to discover and to apply the correct answers to 
 these questions, and in doing this it exhibits the liberalism 
 that characterizes all true science. It seeks its knowledge from 
 all sources and by all legitimate means. All that it acquires 
 it puts to the rigid, critical test of experiment, and it discards 
 all that which does not stand this test. It thus represents a 
 great body of selected scientific knowledge, which is the best 
 that science can offer to-day. To-morrow its knowledge will 
 be more abundant and more exact, and as science continually 
 advances, medical science will keep pace. Its followers are 
 terribly in earnest in their warfare against disease. Like 
 the intrepid Ulysses, they are 
 
 ..." strong in will 
 To strive, to seek, to find, and not to yield." 
 
176 SCIENTIFIC FEATURES OF MODERN MEDICINE 
 
 The altruism of men of medicine has become proverbial. 
 Their heroism in investigating and treating disease is often 
 put to the test, and is rarely foimd wanting. Their ideals are 
 high, and they can be trusted to do what is within their power 
 to put an end to the ills of suffering humanity. Yet it should 
 be borne in mind that scientific medicine unaided has a well- 
 nigh impossible work before it. If it is to accomplish the 
 final banishment of disease, it must have the sympathetic 
 cooperation and encouragement of mankind, in whose inter- 
 ests it continually labors. 
 
INDEX 
 
 Abdomen, surgery of, 138. 
 
 Abrin, production of antibodies by, 
 
 97. 
 Abscesses, vaccine for, 104. 
 Active principles of drugs, 49. 
 Adaptability of body to environment, 
 
 44,46. 
 Adrenal bodies, effects of removal of, 
 
 43 ; growth of tissues of, outside 
 
 body, 152. 
 Amboceptor, 74. 
 Amino-acid in protein, 6. 
 Amyl nitrite, physiological action of, 
 
 51. 
 Ansesthesia, history of, 133 ; nature 
 
 of, 53 ; opposition to, 134 ; spinal, 
 
 135. 
 Anaesthetics, general, 133 ; local, 135 ; 
 
 physiological action of, 53. 
 Anima as directing power in vital 
 
 actions, 20. 
 Animal experimentation, 160 ; in 
 
 cancer, 118; in infectious diseases, 
 
 87 ; opposition to, 161. 
 Animals, healing of wounds by, 47. 
 Anophelea, 80. 
 
 Anthraz, discovery of germ of, 64. 
 Antibacterial substances, 74. 
 Antibodies, 73 ; specificity of, 75. 
 Antitoxin, 74, 77 ; of diphtheria, 90 ; 
 
 of tetanus, 93 ; of cerebro-spinal 
 
 meningitis, 94. 
 Antivaccination, 100. 
 Antivenene, 97. 
 Antivivisection, 161, 165. 
 Appendicitis, 139. 
 Appendix vermiformis, 139. 
 Archeus, as directing power in vital 
 
 actions, 20 ; as cause of disease, 27. 
 Archimedes' experiment, 156. 
 Armamentarium of physician, 48. 
 Arseno-phenyl-glycin in sleeping sick- 
 ness, 52. 
 Arterial pressure, 35, 158. 
 
 Arteries, pressure in, 35, 158 ; trans- 
 plantation of, 150. 
 
 Atozyl in sleeping sickness, 62. 
 
 Atropin, as active principle, 49 ; 
 physiological action of, 51. 
 
 Augmentor nerves of heart, 158. 
 
 Auscultation, 32. 
 
 Axone, 13. 
 
 Bacillus, 67; coryzce segmentosusi 
 82. 
 
 Bacon, Francis, on medicine, 1. 
 
 Bacteria, 66 ; action of, on body, 72 ; 
 and body cells, Ehrlich's scheme of, 
 76; and leucocytes, 12, 45, 77, 
 104 ; beneficent, 69 ; body's de- 
 fenses against, 45, 71, 73 ; carriers 
 of, 84, 108; discovery of, 65; 
 dissemination of, 83 ; entrance 
 of, into body, 69, 71 ; in woundSt 
 136 ; spores of, 67. 
 
 Bactericidal substances, 74. 
 
 Bacteriology, rise of, 64. 
 
 Bacteriolysins, 74. 
 
 Bacteriolytic substances, 74. 
 
 Bathing, therapeutic effects of, 56. 
 
 Belladonna, 49, 51. 
 
 Biceps muscle, phenomena of con- 
 traction of, 15. 
 
 Bichat, discovery of tissues by, 4. 
 
 Bismuth, subnitrate of, physiological 
 action of, 54. 
 
 Blood, 11; and brain, 58; circula- 
 tion of, 13 ; coagulation of, 45 ; in 
 diagnosis, 38; loss of, 44; molec- 
 ular concentration of, 39 ; trans- 
 fusion of, 147. 
 
 Blood corpuscles, 11; red, 12, 38; 
 white, 12, 38, 45, 77, 79. 
 
 Blood plasma, 11. 
 
 Blood plates, 11. 
 
 Blood pressure, 35, 158. 
 
 Blood serum, 89; freezing point of, 
 39. 
 
 177 
 
178 
 
 INDEX 
 
 Body, adaptability of, to environ- 
 ment, 44, 46 ; chemical changes in, 
 9 ; chemical composition of, 5 ; 
 chemical elements in, 5 ; functions 
 of, 6, 17, 22 ; growth of. Ill ; as in- 
 dustrial plant, 10 ; as machine, 6 ; 
 and mind, 18, 57, 172; popular 
 ignorance of, 2, 167 ; structure of, 
 4 ; temperature of, 23. 
 
 Bone, growth of, outside body, 152. 
 
 Brain, and blood, 58; conduction 
 within, 15 ; functions of, 16, 146 ; 
 localization of functions in, 16, 146 ; 
 and mind, 19, 59 ; removal of por- 
 tions of, 44, 146 ; surgery of, 144 ; 
 tumors of, 145. 
 
 Bronchitis, 82. 
 
 Bulb, functions of, 16. 
 
 Cabot on cures by Christian Science, 
 174. 
 
 Calorimeter, respiration, 10. 
 
 Cancer, cells, 111 ; destruction of, in 
 situ, 117; and erysipelas, 121; 
 growth of. 111 ; growth of, out- 
 side body, 115 ; hypotheses con- 
 cerning growth of, 114; hypo- 
 thetical germ of, 112; immunity 
 to, 119 ; inheritance of, 113 ; in- 
 vestigation of, 118 ; not contagious, 
 113 ; nutritive conditions of growth 
 of, 119; problem of, 110, 121; 
 serums for, 121 ; statistics of, 113 ; 
 surgery of, 117; transplantation 
 of, in animals, 118; treatment of, 
 116; vaccines for, 121. 
 
 Carbolic acid in surgery, 136. 
 
 Carcinoma, 114. 
 
 Cartilage, growth of, outside body, 
 152. 
 
 Casts in urine, 40. 
 
 Cells, 5 ; cancer. 111 ; nerve, 13. 
 
 Central nervous system, conduction 
 in, 15 ; connection of, with rest of 
 body, 14 ; localization of function 
 in, 16, 146. 
 
 Cerebral cortex, functions of, 17, 146. 
 
 Cerebro-spinal meningitis, 94; car- 
 riers of, 85 ; and leucocytic extract, 
 105 ; mortality of, 95; serum for, 94. 
 
 Cerebrum, functions of, 17, 146. 
 
 Chemical changes in body, 9. 
 
 Chemical composition of body, 5. 
 
 Chemical elements in body, 5. 
 
 Chest, anatomy of, 142 ; surgery of, 
 141. 
 
 Chicken cholera, immunity of man 
 to, 105. 
 
 Chloroform, discovery of, as anses- 
 thetic, 133. 
 
 Cholera, and antibodies, 78, 107 ; and 
 house flies, 108 ; transmission of, 
 84; vaccination against, 103. 
 
 Cinchona, 49. 
 
 Clinical thermometer, 33. 
 
 Christian Science, 172. 
 
 Cocaine as aneesthetic, 135. 
 
 Coccus, 67. 
 
 "Cold," 82, 109. 
 
 Coles, William, herbarist, 49. 
 
 Complement, 74. 
 
 Connective tissue, growth of, out- 
 side body, 152. 
 
 Consciousness, 18, 59, 62. 
 
 Consumption, see Tuberculosis. 
 
 Cornea, growth of, outside body, 152. 
 
 Cortex of cerebrum, functions of, 17, 
 146. 
 
 Cretinism, 9, 55. 
 
 Crotin, production of antibodies by, 
 97. 
 
 Cowpox, 99. 
 
 Death rate, meaning of the term, 90 ; 
 also see Mortality. 
 
 Demon as cause of disease, 24. 
 
 Dendrite, 13. 
 
 Depressor nerves, 158. 
 
 Diagnosis, inexactness of, by Chris- 
 tian Science, 173 ; methods of, 31 ; 
 mistakes of, 40. 
 
 Digitalis, physiological action of, 51. 
 
 Dioxy-diamido-arseno-benzol, as spe- 
 cific for syphilis, 52. 
 
 Diphtheria, antibodies, 78, 106; 
 carriers of, 84, 85 ; mortality of, 
 92, 93 ; transmission of, 83 ; vacci- 
 nation against, 104. 
 
 Diphtheria antitoxin, 90 ; duration of 
 action of, 93, 106 ; statistics of, 92, 
 93. 
 
 Disease, body's defenses against, 42, 
 71, 73, 78; classification of, 30; 
 complexity of, 23 ; definition of, 22 ; 
 
INDEX 
 
 179 
 
 demoniac theory of, 24 ; functional, 
 22 ; germs of, 65, 79 ; infectious, 
 65 ; structural, 22 ; symptoms of, 
 24 ; symptoms of infectious, 72. 
 
 Disinfectants, 68. 
 
 Dog distemper, immunity of man to, 
 105. 
 
 Drugs, 48; active principles of, 49; 
 experimentation with, 50 ; fate 
 of, in body, 54 ; nature of physio- 
 logical action of, 53 ; physiological 
 action of, 51 ; selective action of, 
 51, 54 ; specific, 52. 
 
 Dumdum fever, protozoan as germ 
 of, 80. 
 
 Dysentery, and antibodies, 79 ; prob- 
 able germ of amebic, 81 ; serum for, 
 96 ; vaccination against, 104. 
 
 Eddy, Mary Baker, and Christian 
 
 Science, 172. 
 Edwards, Jonathan, death of, from 
 
 inoculation, 99. 
 Ehrlich, on relation of bacteria and 
 
 body cells, 76 ; and specific drug 
 
 for syphilis, 52, 163 ; on specificity 
 
 of antibodies, 75. 
 Electrocardiograph, 34. 
 Emotions, expression of, 57. 
 Empiricism, 3, 47. 
 Endotoxins, 72, 75. 
 Environment, adaptability of body 
 
 to, 44, 46. 
 Epilepsy, surgery in, 147. 
 Equilibrium, maintenance of, by 
 
 eyes, 44. 
 Erysipelas, and leucocytic extract, 105; 
 
 serum for, 96. 
 Erythrocytes, 12, 38. 
 Ether, as anaesthetic, 133 ; as direct- 
 ing power in vital actions, 20. 
 Evolution of organs and functions, 
 
 17. 
 Exophthalmic goiter, 9. 
 Exotoxins, 72. 
 Experimentation, on animals, 160; 
 
 on heart, 157 ; in medicine, 154 ; 
 
 nature of, 155. 
 Eye, imperfections of, 88. 
 
 Fermentation, cause of, 136. 
 Fits, surgery in, 147. 
 
 Flies as carriers of disease germs, 83, 
 
 84, 96, 108. 
 Function, alteration of, in disease, 22 ; 
 
 evolution of, 17; examples of, 6; 
 
 nature of, 6. 
 
 Galen's experiment on arteries, 156. 
 
 Gall bladder, surgery of, 141. 
 
 Gall stones, 141. 
 
 Galvani's experiments on animal 
 eleccricity, 163. 
 
 Germicides, 68. 
 
 Germs of disease, 65, 79. 
 
 Glands, functions of, 8. 
 
 Glosaina pcUpalis, 81. 
 
 Goitre, exophthalmic, 9. 
 
 Growth, of body. 111 ; of cancer. 111 ; 
 of cancer outside body, 115 ; of tis- 
 sues outside body, 152. 
 
 Hales' measurement of blood pres- 
 sure, 36. 
 
 Haller's experiment on muscle, 156. 
 
 Harvey's experiments on circulation 
 of blood, 156. 
 
 Hay fever, serum for, 97. 
 
 Healing art, beginnings of, 47; and 
 priests, 47. 
 
 Healing of wounds by animals, 47. 
 
 Heart, diagnosis of disorders of, by 
 electrocardiograph, 34 ; disease 
 of valve of, 23 ; disorders of, 27 ; 
 experiments on, 143, 157 ; func- 
 tions of, 6 ; nerves of, 168 ; nor- 
 mal variation in rate of beat of, 
 23 ; surgery of, 143. 
 
 Hemoglobin in diagnosis, 38. 
 
 Hemophilia, 148. 
 
 Hippocrates, 25. 
 
 Hiss' treatment of infectious diseases, 
 104. 
 
 Holmes and stethoscope, 32. 
 
 Homeopathy, 170. 
 
 House flies as carriers of disease 
 germs, 83, 84, 96, 108. 
 
 Humoral pathology, 26. 
 
 Humors, 25. 
 
 Hydrophobia, 100 ; ancient remedies 
 for, 100 ; mortality of, 103 ; Pas- 
 teur's work on, 65, 101 ; prevention 
 of, by muzzling, 108; probable 
 germ of, 81; procedure in vacci- 
 
180 
 
 INDEX 
 
 nation against, 102 ; transmission 
 
 of, 84. 
 Hypnosis in psychotherapy, 62. 
 Hysteria, 61. 
 
 Ignorance of human body, 2, 167. 
 
 Immune body, 74. 
 
 Immunity, 105 ; antitoxic, 106 ; 
 bacteriolytic, 106; to cancer, 119; 
 phagocytic, 106. 
 
 Infantile paralysis, 95 ; carriers of, 
 85 ; germ of, unknown, 81 ; and 
 house flies, 96 ; mortality of, 95. 
 
 Infectious diseases, 65 ; Hiss' treat- 
 ment of, 104 ; isolation of, 109 ; 
 prevention of, 107; symptoms of, 
 72 ; treatment of, 86 ; uncertainty 
 as to causative organisms of, 81. 
 
 Influenza, bacillus of, in "colds," 83 ; 
 carriers of, 85. 
 
 Inhibitory nerves of heart, 158. 
 
 Inoculation of smallpox, 98. 
 
 Internal secretion, 8, 54. 
 
 Intestine, surgery of, 139. 
 
 Ions, 6. 
 
 Jenner and smallpox, 99. 
 Jensen on transplantation of tumors, 
 119. 
 
 Kala azar, protozoan as germ of, 80. 
 
 Kidney, functions of, 8 ; growth of 
 tissues of, outside body, 152 ; in- 
 ternal secretion of, 9 ; results of 
 loss of one, 43 ; surgery of, 141 ; 
 transplantation of, 151. 
 
 Kircher, first to see bacteria, 65. 
 
 Laboratories, bacteriological, 87 ; 
 
 medical, 159. 
 Laboratory, as agent in medical 
 
 progress, 3 ; first pharmacological, 
 
 49 ; first physiological, 159. 
 Laennec and stethoscope, 32. 
 Laryngitis, 82. 
 
 Leeuwenhoek and bacteria, 65. 
 Leg, transplantation of, 151. 
 Leucocytes, and bacteria, 45, 77, 79 ; 
 
 extract of, 105 ; functions of, 12 ; 
 
 number of, in health and disease, 38. 
 Lister and antiseptic surgery, 136. 
 Liver, disorders of, 29 ; functions of, 
 
 7 ; internal secretion of, 9 ; re- 
 
 moval of portion of, 44; surgery 
 of, 140. 
 
 Living substance, 5. 
 
 Lockjaw, and antibodies, 106; anti- 
 toxin of, 93 ; transmission of, 83. 
 
 Loeb on transplantation of tumors, 
 119. 
 
 Lung, functions of, 7 ; results of loss 
 of one, 43 ; surgery of, 142. 
 
 Lymph, 13. 
 
 Magic in the healing art, 47. 
 
 Malaria, germs of, 80 ; prevention of, 
 108; quinine for, 52, 86; trans- 
 mission of, 84. 
 
 Measles, germ of, unknown, 81 ; 
 immunity to, 105. 
 
 Mechanism in vital actions, 21. 
 
 Mediastinal space, 142. 
 
 Medicine, ancient, 154; limitations 
 of, 169; modern, 154; popular 
 distrust of, 1, 165; popular igno- 
 rance of, 2 ; pure and applied science 
 in, 163 ; supremacy of scientific, 175. 
 
 Medicine man, 47. 
 
 Medulla oblongata, functions of, 16. 
 
 Meningitis, epidemic cerebro-spinal, 
 94 ; carriers of, 85 ; and leucocy tic 
 extract, 105 ; mortality of, 95 ; 
 serum for, 94. 
 
 Meningococcus, 94. 
 
 Mental healing, 56, 172. 
 
 Mercury for syphilis, 86. 
 
 Metchnikoff and phagocytosis, 45, 77. 
 
 Micrococcus catarrhalia, 82. 
 
 Microscope in diagnosis, 37. 
 
 Milk, bacteria of, 107 ; as carrier of 
 disease germs, 83, 84, 107; purifi- 
 cation of, 108. 
 
 Mind, 18, 59 ; and body, 18, 57, 172 ; 
 and brain, 19, 59 ; and disease, 56, 
 172 ; subconscious, 62. 
 
 Mithradates' experiments with drugs, 
 50. 
 
 Moli^re on medicine, 166. 
 
 Montagu, Lady Mary Wortley, and 
 inoculation of smallpox, 98. 
 
 Montaigne on medicine, 165. 3 
 
 Morphine, discovery of, 49. 
 
 Mortality, case, 90; of cerebro- 
 spinal meningitis, 95 ; of diph- 
 theria, 92, 93 ; of infantile paraly- 
 
INDEX 
 
 181 
 
 sis, 95; of major surgical opera- 
 tions before antiseptics, 135 ; mean- 
 ing of term, 90 ; of operation for 
 appendicitis, 140 ; of plague, 104 ; 
 of rabies, 103 ; of removal of gall 
 bladder, 141 ; of smallpox, 99 ; 
 total, 90 ; of tuberculosis, 122 ; 
 of tuberctilosis, after tuberculin, 
 127. 
 
 Morton and ether, 133.~ 
 
 Mosquito, as carrier of malaria, 80, 
 84, 108 ; as carrier of yellow fever, 
 84, 108. 
 
 Mucous membrane, growth of, out- 
 side body, 152. 
 
 Mumps, germ of, unknown, 81. 
 
 Myxedema, 9, 55. 
 
 Natural selection, 42. 
 
 Nerve-cell, 13. 
 
 Nerve-centers, 16. 
 
 Nerve-fibeia, 14; afferent, 14; cen- 
 trifugal, 14; centripetal, 14; clas- 
 sification of, 15 ; efferent, 14 ; 
 growth of, outside body, 152. 
 
 Nerves, 14; augmentor, 158; de- 
 pressor, 158 ; excitatory, 15 ; in- 
 hibitory, 15 ; motor, 15 ; secretory, 
 15 ; sensory, 14, 15 ; vasocon- 
 strictor, 36, 158; vasodilator, 36, 
 158 ; vasomotor, 36, 158. 
 
 Nervous impulses, 14. 
 
 Nervous principle aa directing power 
 in vital actions, 20. 
 
 Nervous system, 13. 
 
 Neurasthenia, 61. 
 
 Neurone, 13. 
 
 Nitrous oxide as anaesthetic, 135. , 
 
 Novocaine as anaesthetic, 135. 
 
 Nux vomica, 49. 
 
 Ophthalmoscope, 33. 
 
 Opsonins, 78, 98, 106. 
 
 Organotherapy, 54. 
 
 Organs, 4; adaptability of, 44, 46; 
 
 evolution of, 17 ; functions of, 6 ; 
 
 structure of, 4 ; transplantation of, 
 
 150. 
 Osteopathy, 170. 
 Ovaries, transplantation of, 151. 
 
 Pancreas, functions of, 8 ; growth of 
 tissues of, outside body, 152; in- 
 
 ternal secretion of, 9; removal of 
 portion of, 44, 141. 
 
 Paracelsus, 26. 
 
 Parathyroid, transplantation of, 
 151. 
 
 Pasteur, achievements of, 65; on 
 fermentation and putrefaction, 136; 
 personal experience with, 65 ; and 
 rabies, 101. 
 
 Pasteurization of milk, 108. 
 
 Pathology, humoral, 26. 
 
 Percussion, 32. 
 
 Pestilence and war, 64. 
 
 Phagocytes, 45, 77, 79. 
 
 Phagocytosis, 45, 77, 79. 
 
 Pharmacology, rise of, 49. 
 
 Pharyngitis,.^82. 
 
 Phrenology, 17. 
 
 Plague, and antibodies, 79, 107; 
 mortality of, 104; prevention of, 
 108 ; serum for, 96 ; transmis- 
 sion of, 84; vaccination against, 
 104. 
 
 Pleural cavities, 142. 
 
 Pneuma, as cause of disease, 26; 
 as directing power in vital actions, 
 20. 
 
 Pneumobacillus, in "colds," 82. 
 
 PneumococQUs, 130; in "colds," 82. 
 
 Pneumonia, 130; and antibodies, 79; 
 carriers of, 85 ; and leucocytic 
 extract, 105 ; serums for, 130 ; vac- 
 cination against, 104, 130. 
 
 Priests and healing art, 47. 
 
 Proteins in protoplasm, 6. 
 
 Protoplasm, 5. 
 
 Protozoa, 79; metabolic activities 
 of, 81. 
 
 Psychasthenia, 61. 
 
 Psychoneuroses, 61. 
 
 Psychotherapy, 56, 172. 
 
 Puerperal fever, serum for, 96. 
 
 Pulse, 35. 
 
 Pure and applied science in medi- 
 cine, 163. 
 
 Putrefaction, cause of, 136. 
 
 Quimby and Christian Science, 172. 
 
 Quinine, as active principle, 49; 
 physiological action of, not selec- 
 tive, 51 ; as specific for malaria, 
 52, 86. 
 
182 
 
 INDEX 
 
 Rabies, 100 ; ancienf; remedies for, 
 100 ; mortality of, 103 ; Pasteur's 
 work on, 65, 101 ; prevention of, 
 by muzzling, 108 ; probable germ 
 of, 81 ; procedure in vaccination 
 against, 102 ; transmission of, 84. 
 
 Radio-therapy, 55. 
 
 Radium, in cancer, 117; as therapeu- 
 tic agent, 65. 
 
 Receptors, 76 ; in immunity, 106. 
 
 Relapsing fever, size of germ of, 67. 
 
 Respiration calorimeter, 10. 
 
 Rhinitis, 82. 
 
 Ricin, production of antibodies by, 97. 
 
 Rinderpest, immunity of man to, 105. 
 
 Roentgen rays, in cancer, 117; as 
 illuminant, 33 ; as therapeutic 
 agent, 55. 
 
 Salvarsan as specific for syphilis, 52. 
 
 Scarlet fever, immunity to, 105 ; 
 probable germ of, 81 ; serum for, 
 96 ; transmission of, 83. 
 
 Science, pure and applied, in medi- 
 cine, 163 ; as characterizing mod- 
 ern medicine, 3. 
 
 Serum, 89 ; for abrin, 97 ; for cancer, 
 121 ; for crotin, 97 ; in diagnosis, 
 39 ; for diphtheria, 90 ; for dysen- 
 tery, 96 ; for erysipelas, 96 ; for 
 hay fever, 97 ; for meningitis, 94 ; 
 for plague, 96 ; for pneumonia, 
 96, 130 ; for puerperal fever, 96 ; 
 for ricin, 97 ; for scarlet fever, 96 ; 
 for snake venom, 97 ; for tetanus, 
 93 ; for tuberculosis, 96, 126 ; for 
 typhoid fever, 96. 
 
 Serum method, 89. 
 
 "Shot-gun" prescriptions, 61. 
 
 Signatures, doctrine of, 48. 
 
 Simples, 49. 
 
 Simpson and chloroform, 133, 134. j 
 
 606 as specific for syphilis, 52. 
 
 Skin, growth of, outside body, 162. 
 
 Skin grafting, 149. 
 
 Sleeping sickness, 80 ; specific drugs 
 for, 52, 163. 
 
 Smallpox, 98; history of, 98; im- 
 munity to, 105 ; inoculation of, 98 ; 
 mortality of, 99 ; probable germ 
 of, 81, 99 ; transmission of, 84 ; 
 vaccination against, 99. 
 
 Snake venom, serum'for, 97. 
 
 Sphygmograph, 35. 
 
 Sphygmomanometer, 37. 
 
 Spinal cord, centers of, 16; conduc- 
 tion in, 15. 
 
 Spirillum, 67. 
 
 Spirits, as cause of disease, 26 ; as di- 
 recting power in vital actions, 20. 
 
 Spleen, growth of tissues of, outside 
 body, 162; removal of, 141; 
 transplantation of, 161. 
 
 Splenic fever, discovery of germ of, 64. 
 
 Spotted fever, see Cerebro-spinal 
 meningitis. 
 
 Staphylococcus, in "colds," 83; and 
 leucocytic extract, 105. 
 
 Statistics, significance of medical, 90. 
 
 Stethoscope, 32. 
 
 Stomach, surgery of, 138. 
 
 Stovaine as anaesthetic, 135. 
 
 Streptococcus in "colds," 83. 
 
 Strychnine, as active principle, 49; 
 physiological action of, 61. 
 
 Subconscious mind, 62. 
 
 Suggestion in psychotherapy, 62. 
 
 Suprarenal glands, effects of removal 
 of, 43 ; growth of tissues of, outside 
 body, 152. 
 
 Surgery, 132 ; antiseptic, 136 ; asep- 
 tic, 137 ; early, 132 ; modern, 137 ; 
 reconstructive, 147 ; septic, 135. 
 
 Symptoms of disease, 24. 
 
 Syphilis, 62 ; specific drugs for, 52, 
 86, 163. 
 
 Temperature of body, 23. 
 
 Tetanus, and antibodies, 106 ; anti- 
 toxin of, 93 ; transmission of, 83. 
 
 Therapy, drUg, 48; hydro-, 56; or- 
 gano-, 54 ; psycho-, 56 ; radio-, 55. 
 
 Thermometer, clinical, 33. 
 
 Thorax, anatomy of, 142 ; surgery 
 of, 141. 
 
 Thyroid, effects of removal of, 43; 
 function of, 9 ; growth of tissues of, 
 outside body, 152 ; transplanta- 
 tion of, 151. 
 
 Tissues, 4 ; growth of, outside body, 
 152. 
 
 Toxins, 72 ; and antitoxins, 74. 
 
 Trachoma, probable germ of, 81. 
 
 Transfusion of blood, 147. 
 
INDEX 
 
 183 
 
 Transplantation of organs, 150. 
 
 Trephining, 145. 
 
 Treponema pallidum, 52, 163. 
 
 Tropococaine as anaesthetic, 135. 
 
 Trudeau's use of tuberculin, 127. 
 
 Trypanosoma, 80. 
 
 Tse-tse fly, 81. 
 
 Tubercle, 124. 
 
 Tuberculin, 104, 126. 
 
 Tuberculosis, 122 ; bovine, 123 ; cam- 
 paign against, 128 ; germs of, 123 ; 
 human, 123 ; hygienic-dietetic 
 treatment of, 127 ; mortality of, 
 122; mortality of, after tuber- 
 culin, 127; prevention of, 129; 
 resistance to, 125 ; segregation of, 
 129 ; serums for, 126 ; sources of 
 infection, 124 ; statistics of, 122 ; 
 transmission of, 84; vaccination 
 against, 104, 126. 
 
 Tumor, 114; benign, 114; of brain, 
 145 ; growth of, outside body, 115 ; 
 malignant, 114. 
 
 Typhoid fever, and antibodies, 97, 
 107 ; and house flies, 108 ; im- 
 munity to, 105 ; serum for, 96 ; 
 size of germ of, 67 ; transmission 
 of, 83, 85, 108 ; vaccination against, 
 103 ; Widal test, in diagnosis of, 
 39. 
 
 Typhoid Mary, 85. 
 
 Typhus fever, germ of, unknown, 81. 
 
 Urine in diagnosis, 39. 
 
 Vaccination, against cholera, 103 ; 
 opposition to, 100 ; against plague, 
 104; principle of, 97; against 
 rabies, 100 ; against smallpox, 98 ; 
 statistics of, 99; against tuber- 
 
 culosis, 104, 126 ; against tjT)hoid 
 fever, 103. 
 
 Vaccine, 97 ; for abscesses, 104 ; for 
 cancer, 121 ; for cholera, 103 ; for 
 diphtheria, 104; for dysentery, 
 104 ; for plague, 104 ; for pneu- 
 monia, 104, 130 ; for rabies, 100 ; 
 for smallpox, 98 ; for tuberculosis, 
 104, 126 ; for typhoid fever, 103. 
 
 Vaccine method, 89, 97. 
 
 Vasoconstrictor nerves, 36, 158. 
 
 Vasodilator nerves, 36, 158. 
 
 Vasomotor center, 36, 158. 
 
 Vasomotor system, 36, 158. 
 
 Veins, transplantation of, 150. 
 
 Vermiform appendix, 139. 
 
 Vis medicatrix natures, 42. 
 
 Vis vitalis, 42. 
 
 Vital actions, nature of, 20. 
 
 Vital force, 21, 27. 
 
 Vitalism, 21. 
 
 Vivisection, 160; in cancer, 118; 
 in infectious diseases, 87 ; oppo- 
 sition to, 161. 
 
 War and pestilence, 64. 
 Warren and ether, 133. 
 Water, as carrier of disease germs, 
 
 83, 84 ; purification of, 107. 
 Widal test for typhoid fever, 39. 
 Wright, and phagocytosis, 77; and 
 
 vaccination against typhoid fever, 
 
 103. 
 
 X-rays, in cancer, 117 ; as Uluminant, 
 33 ; as therapeutic agent, 55. 
 
 Yellow fever, germ of, unknown, 81 ; 
 immunity to, 105 ; prevention of, 
 108 ; transmission of, 84. 
 
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