216 THE BREEDING OF ANIMALS 



that we have two horses under consideration, of the same 

 ancestry. One horse has through germinal variation 

 been endowed with an ability to trot or run at a certain 

 speed without training. The other horse cannot attain 

 the same speed except as the result of long and careful 

 training. They have attained the same rate of speed, 

 but one has acquired this speed through the influence 

 of environment and this increased speed becomes, there- 

 fore, a mere modification. The other horse owes his 

 ability to go fast to a variation in the fundamental con- 

 stitution of the germ substance. The latter horse will 

 be the better breeder because germinal variations are 

 transmitted, and modifications which result from the 

 influence of environment are apparently not transmitted. 



