20 National Life 



gravity, we shall cease to struggle against 

 it. This does not mean a fatal resignation 

 to the presence of bad stock, but a conscious 

 attempt to modify the percentage of it in our 

 own community and in the world at large. 

 Let me illustrate what I mean. A showman 

 takes a wolf and, by aid of training and 

 nurture, a more or less judicious administra- 

 tion of food and whip, makes it apparently 

 docile and friendly as a dog. But one day, 

 when the whip is not there, it is quite possible 

 that the wolf will turn upon its keeper, or 

 upon somebody else. Even if it does not, 

 its offspring will not benefit by the parental 

 education. I don't believe that the showman's 

 way can be a permanent success ; I believe, 

 however, that you might completely domesti- 

 cate the wolf, as the dog has been domesti- 

 cated, by steadily selecting the more docile 

 members of the community through several 

 generations, and breeding only from these, 

 rejecting the remainder. Now, if you have 

 once realized the force of heredity, you will 

 see in natural selection the choice of the 

 physically and mentally fitter to be the 

 parents of the next generation a most 



