86 Dynamic Evolution 



Whether the present variation is due to 

 accident or to the operation of a law of 

 nature we may determine by examining the 

 sires in detail and learning what relationship 

 existed between the ages of the different ones 

 and the work they performed. 



Examining the 45 sires in detail we find 

 that they range from 3 to 23 years of age, 

 and when we compare these ages with the 

 years in which these horses were on the race 

 track, we find that they got their 2 : 10 sons 

 at dates very close to the dates when they 

 retired from the track. We know that a 

 horse is at his highest dynamic development 

 at the close of his racing career, and that 

 thereafter, in the great majority of cases, he 

 loses energy by idleness. If the energy which 

 a horse acquires by hard work is not trans- 

 mitted to offspring, then it is very strange 

 indeed that, of the thousands of foals got 

 by these 45 sires, only those sons which were 

 got when the sires were at their highest 

 dynamic development and lowest fertility 

 were able to get into the 2 : 10 class. 



