130 THE NATURE AND ORIGIN OF LIFE 



only secondarily, by the intermediary of this mechanism, 

 acts on the smallest independent units of the individual, 

 that is, on its chemical constitution. 



This is Lamarckian variation. 



The second direct genesis of variations comprises 

 those cases in which the influence of the surrounding medium 

 is directly exercised on the smallest independent units 

 without passing by the intermediary of the mechanism. 

 Such variations may, therefore, be no matter what so far as 

 the mechanism is concerned ; some may be favourable to it, 

 others unfavourable, as chance may have it. 



This is Darwinian variation, in which selection intervenes 

 only after the fact a secondary adaptation by the disap- 

 pearance of unadapted individuals. 



A rough example will bring out the difference between the 

 two. Take a rat-trap with the spring set : if I loose the 

 spring the trap works as a trap, manifests its mechanism ; 

 I have acted on the spring in a way corresponding to the 

 cinetogenesis of Cope. If, on the contrary, without touch- 

 ing the mechanism, I apply a coat of paint to the different 

 pieces of the apparatus, I treat it as I would no matter 

 what object that is or is not a rat-trap ; I act according to 

 physiogenesis. The example is bad because the rat-trap is 

 not alive ; once it has worked as a trap it is unfitted to begin 

 over again of itself, whereas a living mechanism after work- 

 ing is still fit to work again. 1 But we find such apparatus 

 endowed with functional assimilation nowhere outside the 

 living world. 



To tell the truth, if we search for examples of physiogenesis 



1 A rat-trap would be alive if, while exercising its normal function 

 of loosing its spring, it should impress on its constituent substances 

 a chemical activity whose result would be a tension of the spring 

 tighter even than before. 



