CH. v] MUTATION 51 



and it would also show that the larger must be in general the 

 ancestors of the smaller. Evolution seems to have proceeded 

 upon a definite plan; "the manner in which it has unfolded itself 

 has been relatively little affected by the various vital and other 

 factors, these only causing deviations this way and that from the 

 dominant plan". 



4-2 



