v AIMS OF EXPERIMENTAL EVOLUTION 253 



of intercourse, it was necessary for him to attend at 

 all costs to his cultures and herds ; it was a matter of 

 life or death. Now, our most civilised nations are 

 unable to produce all they need ; some work in one 

 line, some in others, and by cooperation and exchange 

 every one is provided with the things he needs, and 

 none feels the necessity of creating new resources. 

 But civilised man must be made to understand that he 

 can considerably increase the latter if he chooses. Such 

 is the practical interest of experimental transformism, 

 and it can in no possible manner interfere with its 

 scientific aim ; both are bound together. 



As to the latter purpose, I must be content with a 

 few words on the principal lines of investigation. Our 

 main aim must be the study of evolution, that is of 

 the derivation of living forms from each other, and 

 the study of natural influences on the process of this 

 derivation. If the evolution hypothesis is true, we 

 must find that new forms of life may be evolved out of 

 pre-existing forms, by means of influences actually 

 operative in Nature, without man's or any other agent's 

 interference. Of course, in experiments on evolution, 

 man must interfere, but he does so only in order to 

 test the real efficiency of what he considers to be the 

 factors of evolution. 



This general line of investigation is not a simple one ; 

 a large number of questions are intimately connected 



