202 Dynamic Evolution 



the farther we go back in horse pedigrees the 

 older the sires appear. 



This elimination coming from selecting for 

 energy by blood-lines is not confined to the sons 

 of young sires. The sons of old horses are also 

 eliminated in large numbers. A critical ex- 

 amination of those horses remaining after several 

 successive selections shows that what was really 

 first eliminated were the sons of those horses 

 which did the least amount of work before being 

 bred, and what was longest retained were the 

 sons of those horses which did the greatest 

 amount of work before they were bred. The age 

 is simply the factor time in work performed, the 

 other factor in important horses being obtainable 

 from horse history. 



Hambletonian was the product of sixty-nine 

 years in three generations in the male line, and 

 Mambrino Chief was the product of sixty-four 

 years in the same generations. Hambletonian 

 came from four known generations of old and 

 hard-worked female ancestors, while Mambiino 

 Chief was out of an old road mare of unknown 

 ancestry. Hambletonian was trained some when 

 young and was driven regularly on the road 

 during his mature life; Mambrino Chief was a 

 failure in the stud in his youth, was taken from 

 the stud and trained and raced, and was later a 

 successful sire. The remarkable difference in the 

 amount of energy found in the offspring of the 



