30 ORGANIC EVOLUTION— PHYSICAL 



(presently to be noticed) which has the support of many 

 eminent men of science. The mere fact, however, that 

 organisms vary more frequently in the direction of their 

 ancestry than in any other direction, appears to me to 

 raise a strong presumption in its favour. But whether 

 it be true or not, this at least is known to be true ; if 

 any characteristic become of little or no importance in 

 the struggle for existence it is certain to undergo 

 retrogression, i. e. cessation of natural selection is 

 invariably followed by retrogression.^ 



' Any interest this chapter may possess will be greatly increased 

 if inconnection with it Mr. Darwin's book, Animals and Plants 

 under Domesticatim, be read. In that great mine of informa- 

 tion many facts bearing on the subject under discussion are to be 

 found. 



