396 



THE AMERICAN NATURALIST [Vol. XLII 



imental zoology, hygiene, bacteriology, pathology and 

 preventive medicine; but in all these there is a large 

 element of pure physiology, and their adherents often 

 deserve the name of physiologists. When I say that the 

 present is preeminently the age of physiology I mean it 

 seriously, since at no time has the physiological spirit, 

 the spirit of examining vital phenomena by the aid of 

 experimentation, so completely permeated and vitalized 

 the biological sciences as now. 



There exist many misconceptions regarding the subject 

 matter and scope of physiology. In the popular mind 

 physiology deals with the life processes of the human 

 body. In reality human physiology is but one of its 

 many interests. It has its anthropocentric aspect. Bio- 

 centric it is in reality. The popular conception of phys- 

 iology as a science of the functions of gross anatomical 

 organs expresses, too, but a small part of the truth. 

 During the middle part of the last century a powerful 

 school of investigators in Germany busied themselves 

 largely with the functions of organs, and strongly im- 

 pressed the science of their time and the popular mind. 

 But one of the pronounced phases of physiological de- 

 velopment in recent years has been a similar rich growth 

 of the study of the life processes of the cell. Another 

 popular misconception is that physiology deals only with 

 the internal parts of organisms— a view that is confuted 

 by the fact that there is now going on much investigation 

 of the mutual relations of organisms and their environ- 

 ment, in other words, an expansion of what has been 

 called external physiology, which might bear the newer 

 title of ecology. But the wide-spread ignorance regard- 

 ing the broad scope of physiology is in part explained 

 by the fact that a large number of professed physi- 

 ologists do busy themselves with, and most academic 

 courses deal largely with, the vital phenomena of the 

 internal parts of higher animals with the image of man 

 ever in the background. The chief cause of this condi- 

 tion in turn is doubtless the rise of the science within 



