ON PROGRESSION. 207 



particular motions to which they have been 

 most accustomed with greater facility than 

 others. Thus horses which have been kept 

 solely to trotting, cannot gallop so fast as they 

 can trot, nor for so long a continuance. But 

 the same powers which enable them to excel in 

 the trot, would also have rendered them fast 

 gallopers, if they had been employed in that 

 action. Hence it is that particular stallions ac- 

 quire the reputation of getting fast trotters, or 

 high leapers ; for as every person who breeds a 

 colt from horses of this description concludes 

 that these qualities must be specifically generated 

 with him, he constantly exercises him in these 

 pursuits, until the muscles which are principally 

 employed acquire a superior strength to the rest 

 of the body, and furnish the animal with the 

 desired quality^ 



Tht 



