CHARACTERISTICS OF LIVING J\L\TTER 13 



plants), and are introduced into the organism from 

 without by its own special activities. In both groups, 

 however, the active living substance or protoplasm 

 consists chiefly of compounds of the same general 

 chemical type, which in both cases undergo similar 

 transformations. The fundamental physiological pro- 

 cesses of .plant and animal cells are thus closely similar. 

 Hence, in general physiology, whose aim is the analysis 

 of the vital process, wherever occurring, organisms of 

 both groups come equally under consideration. 



