4 MAN AN ADAPTIVE MECHANISM 



The old restricted viewpoint, which led pathologist 

 and clinician to regard disease as an isolated phenom- 

 enon, unrelated to the normal processes of the body, 

 is giving way to the more enlightened view that disease 

 is related to every factor in the life of the species. The 

 logical step from this conclusion is to an inquiry into the 

 past, as well as the present environment of the species. 

 Medical progress, which began with the study of dead 

 forms and gained a great impulse from the observation 

 of living processes, is now face to face with the necessity 

 for making a complete biologic picture of the evolution 

 of both the form and the functions of organisms. 

 Phylogeny, or the study of the ancestral life of species, 

 will probably play a more important role in future 

 medical research. 



Had Darwin and Herbert Spencer applied the prin- 

 ciple of natural selection to physiology as completely as 

 the former applied it to anatomy and to gross behavior, 

 they would undoubtedly have left to us an important 

 compilation of data, thus establishing the basis for a 

 constructive theory of medicine, such as medicine has 

 never possessed. Had either Darwin or Spencer applied 

 the fundamental principle of continuity of development 

 to the functions as well as to the structure of the organ- 

 ism, we should have been saved from much of the con- 

 fusion which has resulted from the old arbitrary division 

 of organic processes into " physical" and "psychical." 

 There is no doubt that this unscientific division has de- 

 layed the solution of those medical problems which are 

 primarily concerned with nervous processes. 



Every step toward the truth makes more evident the 

 fundamental unity of natural phenomena and helps 



