Defensive Ferments of the Animal 



Organism. 



THE question has frequently been raised, whether 

 unicellular organisms exhibit simpler processes, in 

 their general organization and metabolism, than do 

 organisms composed of numerous cells. A priori, 

 it is conceivable that organisms of a morphologically 

 simpler construction are composed of simpler com- 

 binations, and that their metabolic processes follow 

 a simpler path, than is the case in those forms of 

 life in which the body is built up by the co-operation 

 of different cells. But all our experience, hitherto, has 

 proved, that even those cells which are constructed 

 on a simple plan morphologically do, when studied 

 from a purely chemical point of view, show exceed- 

 ingly complicated relations. Indeed, the study of 

 the processes of metabolism in unicellular forms of 

 life is a study all the more difficult, in comparison 

 with that of more complicated organisms, in that, in 

 the former, it is so difficult to separate the actually 

 i 



