GENETICS AND BREEDING 173 



only with the greatest difficulty, if at all. It is, I 

 believe, fair to say that there is at present no 

 critical, unchallenged evidence that any alteration 

 can be produced. This matter has recently been 

 discussed in a most able manner by East.^ The 

 weight of evidence at present indicates that selec- 

 tion does not act in the manner it was long sup- 

 posed to, in accordance with Darwin's interpreta- 

 tion. It appears that selection, however stringent 

 or long continued, is powerless to alter in any way 

 the original potentialities of the germinal basis 

 of a unit character. Selection appears to be es- 

 sentially a process of sorting out from a mixture of 

 heritable variations what is already there, and not 

 a germinally creative or germinally additive pro- 

 cess. 



So far this discussion has been approached from 

 the standpoint solely of animal breeding. It is 

 perhaps allowable, even before this animal section, 

 to digress for a little and discuss plant breeding. 

 The ultimate objective point of the animal breeder 

 is the same as that of the plant breeder ; namely, 

 the greatest possible improvement of animals and 

 plants and their adaptation to the needs of man. 

 The practical method of working towards this 

 goal is, however, somewhat different in the two 

 fields. The animal breeder almost exclusively 

 works towards the amelioration of existing fixed 

 and "pure" breeds. Especially among the larger 



^ American Naturalist, 1912. 



