198 EVOLUTION 



tion, and this it may be a degree more perfect, 

 for others. 



(8) But we must not think of the matter too 

 fatalistically, as if organisms were always like 

 helpless fishes, around which the environ- 

 mental net closed, only the little ones getting 

 through the meshes. True, they cannot 

 by taking thought increase or decrease their 

 stature, even to save their lives; yet they are 

 fertile in device, persistent in endeavour. 

 Even the worm will turn; even the plant will 

 answer back. Living creatures are agents; 

 they thrust as well as parry; they act on their 

 surroundings, modifying them; they are ever 

 seeking out new environments, and conquering 

 them. 



The foregoing analysis has sufficiently 

 shown that the range of relations between the 

 living creature and its surroundings is a very 

 complex one, of functional dependence, of 

 periodic punctuation, of transient adjustment, 

 of more lasting adjustment, of permanent 

 modification, of variational stimulus, of elimi- 

 nation or selection, up to active initiative upon 

 the organism's part. The evolutionary import 

 of these relations is no doubt even more intri- 

 cate than we can yet see. The old theories 

 of direct adaptation in response to altered 

 environmental conditions, or as the result 



