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NATURE 



[August 6, 1891 



itself and also to some extent— in this country at least — in the 

 education and training of the men who enter it. We notice, 

 first, that a very great increase has occurred in the knowledge 

 of the nature, causation, and treatment of diseases possessed by 

 the profession as a whole, but perhaps a still greater gain is the 

 general adoption of the experimental method by which most of 

 our recent knowledge has been acquired, and from which we 

 may hope for even greater advantages in the future. In corre- 

 spondence with the acquirement of knowledge, we notice also a 

 great alteration in the teaching of medicine, and especially 

 prominent is the tendency to make such teaching practical 

 instead of theoretical by training men to place their dependence 

 upon objective facts, and not to receive without experimental 

 data the theories or speculations of any master, however great 

 he may be. . . . 



Direction of Advance. —The greatest advance made in the 

 last twenty-five years has been in the direction of the accumula- 

 tion, co-ordination, and teaching of facts instead of theories, of 

 the phenomena of Nature as opposed to the fancies of the human 

 mind. 



Co-ordination of Facts. — But the mere accumulation of facts 

 is of little use unless they can be so arranged, compared, and 

 grouped as to bring them into relationship with some general 

 law, and this we find in the world's history has been done from 

 time to time by some master-mind. . . . 



Influence of Danuin. — Medicine, both in its principles and 

 practice, is really a subdivision of biology, and this, like all 

 other branches of knowledge, has been most profoundly modi- 

 fied by the general acceptance of Darwin's great thoughts — the 

 doctrine of evolution, the struggle for existence, and the survival 

 of the fittest. Wherever we turn we find that Darwin's influence 

 has modified the direction of thought, and whether the study 

 concerns the evolution of the elements, the evolution of the planet- 

 ary systems, of living beings, of communities, of customs, of laws, 

 of hterature, science, or art, in every department of human know- 

 ledge we find that men, consciously or unconsciously, are influenced 

 by Darwin's work. It is with shame I confess that five-and-twenty 

 years ago, although I had taken a University degree not only in 

 medicine but in science, and might therefore be supposed to be 

 acquainted with his work, I did not even know of the existence 

 of his "Origin of Species," and I first heard its name in Vienna 

 from the lips of an Austrian who was speaking of it in terms of 

 the highest praise. "What is it?" I asked, and my question 

 then seemed to cause my foreign friend as much astonishment as 

 it causes myself now, when the possibility of such ignorance 

 seems to me, as it must to you, almost incredible, and yet such 

 was the fact. The publication of Darwin's " Origin of Species," 

 in 1859, has done more to change the current of human thought 

 than anything else for centuries, but while its influence is every- 

 where felt, biology and all its subdivisions have been more 

 especially affected. 



Changes in Medical Students. — But great as the changes have 

 been during the last five-and-twenty years in the profession 

 itself, they are perhaps quite as great in the men who enter 

 it. . . . 



Long ago the doctor's means of diagnosis consisted in inspect- 

 ing the tongue, feeling the skin, counting the pulse, shaking the 

 urine, and looking at the motions and the sputum. But now, in 

 addition to a thorough training in auscultation and percussion, 

 students have to learn the use of the laryngoscope, ophthalmo- 

 scope, and otoscope, and the application of electricity. They 

 have to acquire a knowledge of the chemistry of the urine and 

 its alterations in disease, and, what takes still more time, they 

 have to learn the microscopical appearances, not only of the 

 tissues and excretions in health, but their alterations in disease, 

 and must be acquainted with the methods of staining so as to 

 detect tubercle bacilli and other disease germs. . . . 



Departments of Greatest Advance. — Five-and-twenty years 

 ago we knew only too well that typhus was infectious, and that 

 pyaemia and erysipelas were likely to spread in a ward when 

 once they got into it, but we did not know then the causes of 

 these diseases as we do now, nor had we the same means at our 

 disposal wherewith to combat them. The departments in which 

 the greatest advances have been made within the last five-and- 

 twenty years are in those of fevers and diseases of the nervous 

 system. A new era in the study of the latter was foreshadowed 

 by the experiments of Fritsch and Hitzig on the brain of the 

 djOg, but it can only be said to have fairly begun with Ferrier's 

 localization of the cortical centres, both motor and sensory, in 

 the brain of monkeys. For the brain of the dog was too unlike 



NO. II 36 VOL. 44] 



that of man for experiments upon it to be of much practical use 

 in the diagnosis of human ailments, while the likeness in the 

 brain of the monkey to that of man at once allowed conclusions 

 drawn from the experiments upon the former to be transferred 

 upon the latter. Yet if we try to describe in one word the de- 

 partment in which medicine has made the greatest progress 

 within the last quarter of a century, that word must be 

 "fevers"; for during this time we have learned to recognize 

 fever by the use of the thermometer in a way we never did 

 before ; we have learned the dependence of the febrile process 

 in the great majority of cases upon the presence of microbes in 

 the organism, and we have become acquainted with an immense 

 number of chemical substances which have the power both to 

 destroy the microbes and to regulate the febrile process. 



Introduction of the Thermometer. — It is true that the ther- 

 mometer was used by Danielssen, in leprosy, before the year 

 1848, and its more general use began with Wunderlich's ob- 

 servations nearly thirty years ago, but it is only within the 

 last five-and-twenty years that its use has become at all 

 general. ... 



Nature of Fever. — The thermometer has not only enabled us 

 to detect the onset and to watch the progress of fever, but in 

 conjunction with microscopical research, physiological experi- 

 ment, and chemical analysis it has enabled us to gain a fuller 

 knowledge of the nature of the febrile process itself. We 

 know that during it the organism is consuming rapidly, or, 

 as Dr. Donald MacAlister graphically says, it is like "a candle 

 burning at both ends," and we have learned scientifically the 

 reasons for the practical treatment, of which Graves was so 

 proud that he wrote as his own epitaph, " He fed fevers." We 

 have learned also, to a great extent, the necessity for the elimina- 

 tion of the waste products, or ashes as we may term them, 

 which the excessive combustion produces, and thus we know 

 why the surgeon is so anxious regarding the result of an 

 operation when the kidneys of his patient are inadequate. 

 For if any febrile attack following the operation should lead 

 to increased demands upon these secreting powers, they 

 might fail to meet it, and the retained excreta would poison 

 the patient. 



New Methods. — The rapid increase in our knowledge has 

 been due not merely to the constant use of old methods, but 

 to the introduction of new ones, and more especially to the 

 general recognition of the fact that the same strategy which has 

 often proved so successful in war is to be applied in attacking 

 complex problems. They are to be separated as far as possible 

 into their several components, and each of these is to be over- 

 come in detail. As presented to us by observation at the bed- 

 side, the problems of disease are too complex for us to solve, 

 and we are only succeeding in doing it by examining the 

 various factors one by one in the laboratory. The greatly in- 

 creased powers of the microscope and the better methods of 

 illumination have been of the greatest service, but their utility 

 would be very much less than it is had it not been for the 

 general introduction of the microtome and the invention of new 

 methods of staining. When I was a student the microtome was 

 only used for cutting sections of wood in the class of practical 

 botany. About that time it was employed by Mr. Stirling, 

 Prof. Goodsir's assistant, in the preparation of animal tissues, 

 but I believe that we owe its general introduction to Prof. 

 Rutherford. The facility with which sections are made by it 

 has made microscopical research much less tedious, and has 

 enabled trained histologists to do more work in a given time, 

 and medical students to acquire knowledge more rapidly. But 

 without the method of staining introduced by Weigert and 

 Ehrlich, we should, even with the best microscopes, be unable 

 to recognize most of the microbes which are so important in the 

 causation of disease. 



Good Out of Evil. — It is very interesting to see how good 

 may come out of evil, and a striking illustration of this is 

 afforded by the history of medicine in the period we are now 

 considering. For it seems to me that we can trace a great 

 part of our knowledge of disease germs and of the antiseptic 

 remedies we use in treatment to the cupidity and stupidity 

 of the Spaniards of the Cordilleras. Their cupidity led them 

 to cut down the cinchona trees of the Andes in order to fill 

 their pockets with the gold they received in exchange for the 

 precious bark, while their stupidity prevented them from 

 planting new trees to replace those which they felled. The 

 consequence of this was that quinine became so dear that it 

 J was evident that anyone who could produce it artificially 



