82 Dynamic Evolution 



count for the excess energy found in the 

 2 : 10 trotter. 



The accumulated energy of parents is 

 measured by the work they performed before 

 reproduction, and that work is measured by 

 two factors — the rate at which work was 

 performed, and the length of time during 

 which such work continued. The first is 

 determined by historical and official records, 

 and the second by the ages of the parents. 

 If both factors are either large or small, the 

 product must be correspondingly large or 

 small, but the size of one factor does not 

 prove the product when the other factor is 

 unknown. It is the product we are after, 

 and while we must look for the product 

 through its factors, any consideration of a 

 factor which does not look ultimately to the 

 product will fail in its object. 



At the time this investigation was made 

 there had been 180 animals which had 

 trotted a mile in 2 : io or less. These horses 

 were born between 1874 and 1898, with 

 average dates of conception in 1889 for mares 



