No. 49S] 



PHYSIOLOGY 



407 



but recent research makes it increasingly clear that they 

 act merely like catalytic agents of inorganic origin. The 

 study of ferments has its dangerous aspect, for more than 

 one investigator, with an eye single to their universality 

 and efficacy, has in his cyclopean enthusiasm come to 

 suspect that all the chemical processes of living organ- 

 isms are mediated by t i i cm, and has even been led to 

 make the narrow and unwarranted assertion that life 

 itself is merely ferment action. 



The discovery of protoplasm and the establishment of 

 the cell theory have exercised a profound influence on the 

 science of function. Until nearly the middle of the last 

 century physiologists were in a sense groping in the dark, 

 for the reason that although they were endeavoring to 

 unravel the mystery of living substance, they had no 

 conception of the real nature of that substance. When 

 the times were ripe they were quick to recognize the value 

 and significance of the new discoveries, and, indeed, 

 played valuable parts in formulating and establishing the 

 new doctrines. With the clear recognition of a definite 

 substance as the physical basis of life, their energies, 

 were more definitely directed than before. One result 

 of this has been the increasing and powerful growth, 

 during the latter part of the last century and the early 

 years of this, of general physiology. The rise of general 



