NOT VITAL ACTIONS. 



invariably does so. The lifeless catalytic body does not 

 necessarily alter in chemical composition during its action ; 

 the living one is always undergoing change in its active 

 state. The first cannot be said to form new material; the 

 last always exhibits this property. Neither the assimilation 

 of food, nor the conversion of food into blood, nor the 

 conversion of blood into organ or texture, can be correctly 

 spoken of as due to catalysis or contact action, for in these 

 processes not only are certain elements of the pabulum 

 taken into the very substance of the matter which is the 

 catalytic agent, but they become a part of the agent itself. 

 In no case does the food directly become blood, or the 

 blood undergo direct conversion into organ or texture, but 

 both food and blood pass through a transition stage during 

 which neither the compounds existing before, nor those 

 which are about to be produced, can be detected. 



If the catalytic platinum could take up and convert the 

 materials around it into platinum and give rise to something 

 differing in composition and properties from itself as well as 

 from the matter around it which it had taken up, an analogy 

 would exist between the phenomena above mentioned and 

 catalysis. If it could be shown that in assimilation, in the 

 conversion of food into blood, and blood into tissue, the 

 pabulum became changed, while the cells like the platinum 

 in catalysis, underwent no change, it might then be correct 

 to regard living cells as catalytic or contact agents, but it 

 has been distinctly proved that nothing save that which is 

 alive can effect changes like those occurring in connection 

 with living cells, and that "living" comprehends more than 

 mere chemical, mechanical, and catalytic changes, or all 

 these together. 



