THE MECHANISTIC THEORY OF LIFE 



mysterious agency is at work, the nature 

 of which is beyond physical and chemical 

 investigation. 



It is only what might be expected on the 

 Darwinian theory of natural selection that 

 the physico-chemical mechanisms within the 

 living body should turn out to be extremely 

 complex, since these mechanisms are the 

 product of natural selection acting through 

 countless generations; and it is folly to go 

 back to vitalism for the mere reason that 

 iving organisms do actually turn out to be 

 very complex. 



/ We must now examine the nature of the 

 Assumption made by the vitalists, and consider 

 to what extent it corresponds with observed 

 facts. Vitalism raises no objection to physical 

 and chemical explanations applied in what 

 is considered their proper place outside the 

 intimate vital processes of living organisms. 

 It assumes, however, that these intimate pro 

 cesses are guided or controlled by an influence 

 which is manifested only in living organisms, 

 and which acts in a manner wholly different 

 from anything known in the inorganic world. 

 The reason for making this assumption is 



