248 EVOLUTION 



struggle and development to species-main- 

 taining ends. The ideal of evolution is thus 

 no gladiator's show, but an Eden; and though 

 competition can never be wholly eliminated 

 the line of progress is thus no straight line 

 but at most an asymptote it is much for our 

 pure natural history to see no longer struggle, 

 but love as "creation's final law." 



Natural selection remains still a vera causa 

 in the origin of species; but the function 

 ascribed to it is practically reversed. It 

 exchanges its former supremacy as the 

 supposed sole determinant among practically 

 indefinite possibilities of structure and func- 

 tion, for the more modest position of simply 

 accelerating, retarding or terminating the 

 process of otherwise determined change. It 

 furnishes the brake rather than the steam or 

 the rails for the journey of life; or in better 

 metaphor, instead of guiding the ramifica- 

 tions of the tree of life, it would, in Mivart's 

 excellent phrase, do little more than apply 

 the pruning-knife to them. In other words, 

 its functions are mainly those of the third 

 Fate, not the first; of Siva, not of Brahma. 



