228 SECRETS OF ANIMAL LIFE 



in terms of the highest values. As to the question 

 whether the factors operative in ordinary organic 

 evolution are more than complications or com- 

 positions of factors which operate in inorganic 

 genesis, we would answer, Much more. For Natural 

 Selection operates on what is not accounted for 

 mechanically, and the sifting process itself is more 

 than mechanical. For the explicit organism can 

 often be seen to play the new cards which the 

 implicit organism has put into its hands. Organ- 

 isms are at times selected by their environment; 

 at other times they select it. They often help 

 to make their own sieves. All our formal state- 

 ments of the tactics of organic evolution are too 

 stiff. They tend to conceal the heart of the matter, 

 of which, in Darwin's footsteps, we are ever getting 

 new glimpses, that living creatures with a will to 

 live, with an insurgent self-assertiveness, with a 

 spirit of adventure, with an endeavor after well- 

 being, do trade with time and have commerce 

 with circumstance, as genuine agents, sharing in 

 their own evolution. 



