THE SPREAD OF VARIATIONS 39 



tion we should have no idea of the beginning or 

 end of the process. So the evolution of species 

 may be progressing by predetermined stages, 

 which need more time for their detection than may 

 be commanded by human observation. But 

 amongst the considerations that may be opposed 

 to this belief there stand the wastefulness of life 

 the creation of millions of living organisms which 

 are born only to be destroyed in immaturity ; and 

 the fact that evolution may be retrogressive 

 that species may descend the scale of life, as the 

 tapeworm and the barnacle have undoubtedly 

 degenerated. These considerations are hardly 

 to be reconciled with the idea of a preordained 

 scheme of evolutionary development, unless we 

 concede that it may be wholly out of accord with 

 our higher ethical ideas. 



We are, however, aware of two forces, very 

 different in themselves, which may have contri- 

 buted to the spread of variations the influences 

 of environment, and the imitative impulse. There 

 appears to be an analogy between the evolution 

 of species and the development of civilization: 

 in both cases novelties arise in individuals and 

 spread to masses. The novelties of civilization 

 new mechanical inventions or artistic ideas, for 

 instance disseminate themselves by their suit- 

 ability to peculiarities of climate or locality (which 

 occasion a desire for them), or by the action of the 

 propensity to imitate, which is one of the strongest 

 of human instincts. If we assume that a chance 

 variation may be in accord with influences of 

 environment which we may not comprehend but 

 should not on this account rule out of existence 

 these influences may very materially assist its 

 possessors in outnumbering their fellows ; and if, 

 in some cases, the occurrence of a variation is 

 actually stimulated by these influences, their 



