284 THE BREEDING OF ANIMALS 



268. Improvement in speed. The ability to go fast 

 at the trot is a development of American horse-breeding 

 enterprise. The first trotting race was held at Boston 

 in 1815. The fastest time made in this race was a mile 

 in three minutes. As the result of interest in trotting 

 races and the invention of light horse-drawn vehicles, 

 the demand for speed at the trot resulted in great improve- 

 ment in this direction. The record time of trotting horses 

 decreased from year to year until at the present day (1916) 

 several horses have been developed that are able to trot 

 a mile in less than two minutes. The examples men- 

 tioned are all noteworthy as examples of man's power to 

 change fundamentally the form and function of the 

 domestic animal. These examples could be indefinitely 

 multiplied. 



269. Selection. All wild forms that have been do- 

 mesticated possess characters of economic value to man. 

 They were domesticated for that reason. These valuable 

 qualities have been, in many cases, greatly improved 

 through the agency of man. So great has been the im- 

 provement in many animal forms that the domesticated 

 animal is markedly different from his wild ancestors. 

 Many varieties, races or breeds exist and each of these 

 differs in important particulars not only from its wild 

 relatives but from all other varieties having similar ances- 

 tral history. 



How have these valuable characteristics come into 

 existence? What natural laws have guided man in the 

 improvement of animals? Are the valuable character- 

 istics of animals due chiefly to inheritance or are they in 

 most part the result of improved conditions which sur- 

 round the domestic animals? Is it possible for us from 

 a study of the history of the achievements of animal- 



