2 NERVE COMPONENTS OF BONY FISHES. 



morphological comprehension of the structure that reac 

 to stimuli of the external environment. This implies a 

 broad philosophical appreciation of the relations between 

 part and part; of the functional, mechanical and other 

 factors which determine the forms of the parts; of the 

 modifications induced by the mechanics of growth during 

 the ontogeny; .and, finally and most important of all, 

 of the phylogenetic history. It is this latter point which 

 most often gives the clue to structure, and this is a justifi- 

 cation for the recognition of comparative anatomy in a 

 scheme of the correlation of sciences for the study of the 

 dynamics and statics of the nervous system. 



A generation ago comparative anatomy in this country 

 was chiefly in the hands of the medical profession, and the 

 medical journals contained many memoirs upon the 

 anatomy of the lower animals, memoirs that are standard 

 sources of information to the biologists to-day. With the 

 development of medical specialties and the advance of 

 specialization in other departments of knowledge, all 

 this is changed and it often happens that the pathologist 

 of to-day, for instance, is acquainted with the normal 

 structure of the organs in the human body, the morbid pro- 

 cesses of which he is investigating, but knows little of 

 their comparative anatomy, histology and embryology. 

 Of course it is not to be expected that under the present 

 conditions pathologists should conduct special researches 

 in comparative anatomy or embryology; nevertheless an 

 acquaintance with the general principles of these sub- 

 jects is indispensable for pathology if this science is to 

 gain a broader and more comprehensive basis. 



How much would be left of the general laws of the 

 science of embryology if all of the facts acquired by the 

 comparative method were stricken out ? And if physi- 



