248 EVOLUTION 



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 ramifications 

 of the tree of life, it would, in Mivart's excel- 

 lent 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. 



