154 Evolution of Aiiliiuil Life. 



As I have said, the laAvs of heredity and variation are 

 little known. It is in this direction, doubtless, that further 

 light may be expected. But there is already light enough 

 to permit us to see that the production of specific animal 

 forms by derivation, and not by independent origin, is the 

 only rational theory we can entertain ; that the Darwinian 

 hypothesis, as noAv reinforced and complemented, is more 

 satisfactory than ever as an explanation of the mode of such 

 derivation ; and that, thus explained, the succession of life 

 upon the globe falls into its place as a harmonious element 

 in what I, for one, conceive to be the vast, complex, yet or- 

 derly and rational expression of an immanent, self-revealing 

 God. 



