20 Darwinism and Other Essays. 



Whether, therefore, it is practicable for us to 

 day to explain every minute peculiarity of any 

 one particular species by an appeal to natural se 

 lection alone is not the main point to be consid 

 ered in estimating the success of the Darwinian 

 theory. The question has a scientific interest of 

 its own which is very great, but it is not the main 

 question. The main point is that, admitting nat 

 ural selection to be a vera causa at all (and this 

 no one denies), the stability of species is proved 

 to be but a contingent and temporary affair. The 

 old notion of an absolute fixity of species is over 

 thrown once for all, and with it the only sem 

 blance of an argument that could ever have been 

 alleged in behalf of the hypothesis of special cre 

 ations. For in considering nearly allied forms, 

 like the lion, tiger, and leopard, their actual con 

 sanguinity would never have been doubted for a 

 moment but for the inability of naturalists to un 

 derstand how the type which appears so constant, 

 when viewed through a short period of time and 

 amid unchanging conditions, should after all be 

 variable. Unable to imagine any probable cause 

 or method of variation by which the descendants 

 of a common feline ancestor should have acquired 

 the divergent characters of lions and leopards, the 

 naturalist either gave up the problem as insoluble, 



