72 THE COW 



the calves of those cows that, judged by his stan- 

 dards, seemed to him best or most desirable. 



In discussing the theory of breeding and the 

 results that have been attained, we have always 

 assumed that these changes have come about al- 

 most wholly through the conscious selection and 

 agency of man. It is altogether probable, how- 

 ever, that a very large part of the modification of 

 our domestic animals has resulted from a natural 

 biologic selection rather than from the deliberate 

 methods and plans of the breeder. An excellent 

 example of how Nature works (and sometimes con- 

 trariwise) with man in his breeding operations is 

 the little Kerry cow or the tiny Shetland pony. 

 These animals are practically dwarfs, not because 

 their owners have systematically selected the off- 

 spring of the smallest mothers, but rather because 

 of a law that runs true throughout all life. The 

 law may be stated thus: "Where the food supply 

 is scanty and uncertain, the size of organisms tends 

 to decrease." 



In any case, there are on our American farms 

 today about twenty different breeds of cattle which 

 are distinguished from each other not only by size, 

 form, or color markings, but more remarkably by 

 functions as well, and yet all of them must ac- 

 knowledge the wild cow of Europe as a common 

 ancestress. 



The larger part of the story of the breeding of 

 the cow is lost in the unwritten past. Certain it 



