POPULAR SCIENTIFIC LECTURES. 



087 



again in relation to fcer, so vigorous nnrt so 

 capable of growth has she become in the 

 fountain of youth of the natural sciences. 



I may, perhaps, retain the impression ot 

 this antagonism, more freshly than those of 

 my contemporaries whom I have the honor 

 to see assembled before me ; and who, hav- 

 ing remained permanently connected with 

 science and practice, have been less struck 

 and less surprised by great changes, taking 

 place as they do by slow steps. This must 

 be my excuse for speaking to you about the 

 metamorphosis which has taken place in 

 medicine during this period, and with the 

 results of whose development you are better 

 acqiminted than I am. I should like the im- 

 pression of this development and of its 

 causes not to be quite lost on the younger of 

 my hearers. They have no special incentive 

 for consulting the literature of that period ; 

 they would meet with principles which ap- 

 pear as if written in a lost tongue, so that it 

 is by no means easy for us to transfer our- 

 selves into the mode of thought of a peiiod 

 which is so far behind us. The course of 

 development of medicine is an instructive 

 lesson on the true principles of scientific in- 

 quiry, and the positive part of this lesson 

 has, perhaps, in no previous time been so 

 impressively taught as in the last generation. 



The task falls to me, of teaching that 

 branch of the natural sciences which has to 

 make the widest generalizations, and has to 

 discuss the meaning of fundamental ideas ; 

 and which has, on that account, been not 

 unfitly termed Natural Philosophy by the 

 English-speaking peoples. Hence it does 

 not fall too far out of the range of my official 

 duties and of my own studies, if I attempt to 

 discourse here of the principles of scientific 

 method, in reference to the sciences of ex- 

 perience. 



As regards my acquaintance with the tone 

 of thought of the older medicine, indepen- 

 dently of the general obligation, incumbent on 

 every educated physician, of understanding 

 the literature of his science and the direction 

 as well as the conditions of its progress, there 

 was in my case a special incentive. In my 

 first professorship at Konigsberg, from the 

 year 1849 to 1856, I had to lecture each win- 

 ter on general pathology that is, on that 

 part of the subject which contains the gen- 

 eral theoretical conceptions of the nature of 

 disease, and of the principles of its treatment. 



General pathology was regarded by our 

 elders as the fairest blossom of medical sci- 

 ence. But in fact, that which formed its 

 essence possesses only historical interest for 

 the disciples of modern natural science. 



Many of my predecessors have broken a 

 lance for the scientific defence of this essence, 

 and more especially Eenle and Lotz. The 

 latter, whose starting-point was also medi- 

 cine, had, in his general pathology and ther- 

 apeutics, arranged it very thoroughly and 

 methodically and with great critical acumen. 



My own original inclination was toward 

 physics ; external circumstances compelled 

 mo to commence the study of medicine. 



which was made possible tome by the liberal 

 arrangements of this Institution. It had, 

 however, been the custom of a former timo 

 to combine the study of medicine with that 

 of the natural sciences, and whatever in thin 

 was compulsory I must consider fortunate ; 

 not merely that I entered medicine at a timo 

 in which any one who was even moderately 

 at homo in physical considerations found a 

 fruitful virgin soil for cultivation ; but 1 

 consider the study of medicine to have been 

 that training which preached more impress- 

 ively and more convincingly than any other 

 could have done, the everlasting principles 

 of all scientific work ; principles which are so 

 simple and yet are ever forgotten again ; so 

 clear and yet always hidden by a deceptive 

 veil. 



Perhaps only he can appreciate the im- 

 mense importance and the fearful practical 

 scope of the problems of medical theory, who 

 has watched the fading eye of approaching 

 death, and witnessed the distracted grief of 

 affection, and who has asked himself the 

 solemn questions, Has all been done which 

 could bo done to ward off the dread event? 

 Have all the resources and all the means 

 which science has accumulated become ex- 

 hausted ? 



Provided that he remains undisturbed in 

 his study, the purely theoretical inquirer may 

 smile with calm contempt when, for a time, 

 vanity and conceit seek to swell themselves 

 in science and stir up a commotion. Or he 

 may consider ancient prejudices to be in- 

 teresting and pardonable, as remains of 

 poetic romance, or of youthful enthusiasm. 

 To one who has to contend with the hostile 

 forces of fact, indifference and romance dis^. 

 appear ; that which he knows and can do, is 

 exposed to severe tests ; he can only use the 

 hard and clear light of facts, and must give> 

 up the notion of lulling himself in agreeable 

 illusions. 



1 rejoice, therefore, that I can once more- 

 address an assembly consisting almost ex- 

 clusively of medical men who have gone 

 through the same school. Medicine was 

 once the intellectual home in which I grew 

 up, and even the emigrant best understands 

 and is best understood by his native land. 



If I am called upon to designate in one 

 word the fundamental error of that former 

 time, I should be inclined to say that it pur- 

 sued a false ideal of science in a one-sided 

 and erroneous reverence for the deductive 

 method. Medicine, it is true, was not the 

 only science which was involved in this error 

 but in no other science have the consequences, 

 been so glaring, or have so hindered progress, 

 as in medicine. The history of this science 

 claims, therefore, a special interest in the 

 history of the development of the human 

 mind. None other is, perhaps, more fitted 

 to show that a true criticism of the sources 

 of cognition is also practically an exceedingly 

 important object of true philosophy 



The proud word of Hippocrates, " Godlike 

 is the physician who is a philosopher," served, 

 as it were, as a banner oi the old. deductive 



