104 Dynamic Evolution 



also represents very closely the time when 

 they produced the offspring most likely to 

 breed on to extreme speed. It is the same 

 thing, extending uniformly through four gen- 

 erations, which we found for the immediate 

 sires of stallions, and when we find such a 

 uniformity extending over nearly forty years 

 of time, it must have a significance. 



And what of the 987 sires without records 

 which appear in these pedigrees at the aver- 

 age age of fifteen years? When we examine 

 them in detail we find that they represent 

 only a little over one hundred separate in- 

 dividuals, the whole number being made up 

 principally of repetitions, some horses many 

 times, some horses a few times, and some 

 horses appearing only once as the sire of 

 some remote dam. When we examine the 

 frequently repeated horses we find them to 

 have all been horses which were driven in 

 harness and driven hard. Some were owned 

 by men who drove them for the mere pleas- 

 ure of driving, some were long in the hands 

 of sports and gamblers of unsavory reputa- 



