i DARWIN'S FORTUITY 13 



natural selection. Darwin was a man 

 so much wiser than all his followers, and 

 there are in his book so many indications 

 of his sense of our great ignorance, that 

 most probably he did grow in the con- 

 sciousness of the necessary incomplete- 

 ness and shortcomings of his own 

 explanations. But there was nothing 

 whatever to startle him in the idea of 

 heredity propagating structural change, 

 through functional use and disuse. This 

 idea was not incongruous with his own 

 more general conception. On the con- 

 trary, it was strictly congruous and 

 harmoniously subordinate. He did not 

 profess to account for all the varieties 

 which emerge in organic forms. Provi- 

 sionally, and merely for the convenience 

 of leaving that subject open, he spoke of 

 them as fortuitous. But to assume the 

 really fortuitous or accidental character 

 of variation to be an essential part of 



