CKOSSING. 115 



suppose that the hereditary qualities of an animal attach 

 to the blood more than to any other fluid or to any 

 of the tissues of the body, or that the blood of a high- 

 bred horse is essentially different from that of another, 

 is entirely erroneous. The qualities of an animal de- 

 pend upon its organization and endowments, and the 

 blood is only the vehicle by which these are nourished 

 and sustained ; — moreover the blood varies in quality, 

 composition and amount, according to the food eaten, 

 the air breathed and the exercise taken. If one horse 

 is better than another it is not because the fluid in his 

 veins is of superior quality, but rather because his 

 structure is more perfect mechanically, and because 

 nervous energy is present in fitting amount and in- 

 tensity. 



For illustration, take two horses — one so built and 

 endowed that he can draw two tons or more, three miles 

 in an hour ; the other so that he can trot a mile in three 

 minutes or less. Let us suppose the blood coursing in 

 the veins of each to be transferred to the other ; would 

 the draft horse acquire speed thereby, or the trotter 

 acquire power ? Just as much and no more as if you 

 fed each for a month with the hay, oats and water in- 

 tended for the other. 



It is well to attend to pedigree, for thus only can we 



know what are the hereditary qualities, but it is not 

 11 



