WILLIAM T. COUNCILMAN 



PROFESSOR OF PATHOLOGICAL ANATOMY, HARVARD 

 MEDICAL SCHOOL 



THE VALUE OF ANIMAL EXPERIMENTATION IN 



PATHOLOGY 



THE great advance in the art of medicine which has come 

 in the last forty years has been due to a greatly increased 

 knowledge of disease. In acquiring this knowledge, ob- 

 servation and experiment must go hand in hand. The 

 study of the phenomena of disease, with their descrip- 

 tion and classification, though important, will not suffice. 

 To explain the phenomena observed, recourse is had to 

 hypothesis, and this must be proved by the experiment. 

 There was but little experimental study of disease prior to 

 1860, and many of the theories which were advanced in 

 explanation of phenomena and on which methods of treat- 

 ment were instituted are known now to have been utterly 

 erroneous. The theory of crasis advanced by so great an 

 observer as Rokitansky, and which by its general accept- 

 ance greatly retarded the advance of knowledge, fell when 

 subjected to the experimental test. By the method of 

 observation we are limited to the study of phenomena 

 exhibited by the sick individual, those variations from 

 normal function which are called symptoms, and the 

 changes in the structure of organs seen in the post-mortem 

 examination to which the symptoms are supposed to be 

 due. To explain the connection between the two, hy- 

 potheses must be advanced, and the hypotheses must be 



