182 MR. DARWIN'S CRITICS v 



waves which break upon the sea-shore are inde- 

 finite, fortuitous, and break in all directions. In 

 scientific language, on the contrary, such a state- 

 ment would be a gross error, inasmuch as every 

 particle of foam is the result of perfectly definite 

 forces, operating according to no less definite laws. 

 In like manner, every variation of a living form, 

 however minute, however apparently accidental, is 

 inconceivable except as the expression of the 

 operation of molecular forces or " powers " resident 

 within the organism. And, as these forces certainly 

 operate according to definite laws, their general 

 result is, doubtless, in accordance with some general 

 law which subsumes them all. And there appears 

 to be no objection to call this an " evolutionary 

 law." But nobody is the wiser for doing so, or has 

 thereby contributed, in the least degree, to the 

 advance of the doctrine of evolution, the great 

 need of which is a theory of variation. 



When Mr. Mivart tells us that his "aim has 

 been to support the doctrine that these species 

 have been evolved by ordinary natural laws (for 

 the most part unknown), aided by the subordinate 

 action of ' natural selection ' " (pp. 332-3), he seems 

 to be of opinion that his enterprise has the merit 

 of novelty. All I can say is that I have never had 

 the slightest notion that Mr. Darwin's aim is in 

 any way different from this. If I affirm that 

 " species have been evolved by variation l (a natural 



1 Including under this head hereditary transmission. 



