82 THE HOESE. 



Perhaps the most striking instance, as it has the 

 certainty of a mathematical demonstration, which 

 can be given of the change of constitution and capa- 

 bility brought about by careful selective breeding in 

 a comparatively short space of time, is seen in the 

 steady progress that has been made in improving the 

 pace of the American fast-trotting horse. Between 

 1818, when records began to be systematically kept, 

 and 1885, the time for a mile heat has been gradually 

 improved from three minutes (the fastest ever ac- 

 complished at the former date, and which previously 

 was not thought possible) to two minutes, eight sec- 

 onds and three-quarters, which was attained on July 

 30 of the last-named year. Although this is at pres- 

 ent the highest record, past experience renders it prob- 

 able that it is not the greatest speed ultimately attain- 

 able. As bearing upon an important biological prob- 

 lem, much discussed at the present time, it would be 

 extremely interesting to ascertain, if it were possible 

 to do so, whether tins result has been acquired solely 

 by breeding from the fastest animals, and so taking 

 advantage of any, even the slightest, variation which 

 occurs in this direction in order to perpetuate the 

 quality in the race j or whether the careful training 

 that the parents have had has been capable of pro- 

 ducing a direct influence upon the offspring. The 

 first case would be an illustration of the effects of 



