THE DOGMA OF EVOLUTION 



such as is externally visible; and indeed he rarely 

 cares for what is internal. He can never act by selec- 

 tion, excepting on variations which are first given to 

 him in some slight degree by nature. No man would 

 ever try to make a f antail till he saw a pigeon with a 

 tail developed in some slight degree in an unusual 

 manner, or a pouter till he saw a pigeon with a crop 

 of some unusual size ; and the more abnormal or un- 

 usual any character was when it first appeared, the 

 more likely it would be to catch his attention. But to 

 use such an expression as trying to make a f antail is, 

 I have no doubt, in most cases, utterly incorrect. The 

 man who first selected a pigeon with a slightly larger 

 tail never dreamed what the descendants of that 

 pigeon would become through long-continued, partly 

 unconscious and partly methodical, selection. "^^ Thus 

 Darwin shows what remarkable results can be ob- 

 tained when slight, accidental variations are directed 

 by man so as to exclude the crossing of a given strain 

 with other individuals of the same species which do 

 not show the same variation. With his mind fixed on 

 the problem of increasing and fixing variations, he 

 did not see a fatal objection to the theory of evolu- 

 tion when it was applied to organisms not subjected 

 to the control of man's will. The objection is this: in 

 spite of all our breeding of pigeons, which has ex- 

 tended through more than three thousand years, two 

 of the most differentiated varieties can interbreed; 



^^ Origin of Species, vol. I, p 44. 



C2183 



