20 THE MECHANISTIC THEORY OF LIFE 



out from the blood, and forcing into the 

 ducts of the tubules the various constituents 

 of urine. Such a mode of statement seems 

 to approximate very closely to vitalism, 

 although, as already pointed out, we have 

 only to presuppose the existence of suitable 

 intra-cellular mechanisms in the cells lining 

 the tubules in order to fit the observed facts 

 with the mechanistic theory of life. 



As another instance we may take the case 

 of oxidation processes occurring in the living 

 body. It was formerly believed that physio 

 logical oxidation is a comparatively simple 

 process, varying in rate, like ordinary oxi 

 dations occurring outside the body, with the 

 supply of oxygen on the one hand, and of 

 oxidisable food-material on the other. When, 

 however, the matter came to be investigated 

 by Pfliiger and others, it was found that this 

 was not the case : for the supply of oxygen 

 and of food-material could be varied within 

 wide limits without altering the rate of 

 oxidation. Hence it was concluded that the 

 living cell regulates its own oxidation pro 

 cesses, and, indeed, all chemical processes 

 occurring within it. This appears to be a 



