194 THE HORSE 



rather than make the attempt to correct the mistake by 

 using the animals which have been varying for the 

 worse. 



It is not easy to determine by the subsequent effects 

 the exact causes of slight variations or the exact time 

 when they are introduced. There is one safe rule 

 endeavor to make all of the conditions of the animal 

 superior to those which formerly prevailed; then when 

 variations appear they are likely to be for the better. 

 The reverse of this is equally true. Inferior conditions 

 produce variations for the worse. 



Keeping these facts in mind, the breeder is ready to 

 begin his selection; provided, however, he has good 

 judgment and a clear-cut mental photograph of the 

 animal he seeks to produce. Selecting an animal does 

 not improve it. The breeder simply takes advantage of 

 the variations for the better due to causes which 

 antedate his choice. By selection, he seeks to eliminate 

 the influence of those individuals which have varied for 

 the worse or have not risen, on the whole, above the 

 average. By selection, he may progress faster than he 

 would if he attempted to raise the progeny of all the 

 herd to a higher average level without selection. 



A herd of bison, if changed from bad conditions and 

 scanty pasturage to improved conditions and abundant 

 food, will, in the course of a few generations, vary for 

 the better; although natural elimination is likely to be 

 more active under bad than under good conditions. 

 It is, then, not natural selection, but improved food and 

 environment, that have produced the variations for the 

 better. 



