154 Dynamic Evolution 



generations of the opposite sex, that the sires 

 of sires were older than the sires of dams, 

 and that the dams of dams were older than 

 the dams of sires, and that this relationship 

 existed in the same way in the pedigrees of 

 stallions, pedigrees of mares, and pedigrees 

 of geldings. Also, that the distribution of 

 race records corresponds to the distribution 

 of ages — that is, the sires of sires were raced 

 more than the sires of dams, and the dams 

 of dams were raced more than the dams of 

 sires. The explanation of this is found in the 

 sexual character of energy acquired after 

 puberty, and the capability of an offspring 

 to transform such an inheritance into an 

 ordinary character when that offspring is of 

 the same sex as that of the parent which 

 acquired the energy. That this explanation 

 is the true one is evident from the fact that 

 a 2 : 10 trotter is produced only when there 

 is a combination of advantageous circum- 

 stances, and the general presence of this 

 relationship shows it to be advantageous. 

 In Holstein-Friesian cattle there is no such 



