MILKING QUALITIES ARTIFICIAL. 181 



passes into the mammary glands, but especially upon the activity 

 of those glands, but the quality is governed more by the internal 

 structure of the animal. 



In subjecting the animal naturally wild, to a state of domes- 

 tication so as to modify its form and system, we do it at the 

 expense of certain qualities for the sake of attaining other 

 qualities better calculated to promote our immediate interests. 

 The vitality or vigor of constitution is weakened as well as the 

 reproductive power, but the formation of fat or the tendency to 

 produce meat, and the profitable yield of milk may be largely 

 increased. Now as these qualities, the extraordinary develop- 

 ment of which is due to domestication, are artificial, there is 

 a constant tendency to revert to the natural condition, so that 

 constant care is required to preserve what we have gained, by 

 careful selection of individual animals from which to breed, 

 especially to see that the male comes from a stock or family 

 remarkable for the production of milk. 



It has been found that animals that possess a strong tendency 

 to secrete fat in the system seldom unite with it a strong ten- 

 dency to secrete milk. Indeed the reverse is commonly true, 

 and there is a marked deficiency in the formation of milk. 

 When food is taken into the system, the first process is that 

 of digestion, then follows the separation or preparation of nutri- 

 tive parts for entering into the circulation of the blood. Indi- 

 vidual animals differ greatly in the completeness with which this 

 process is effected. In some there is a much greater loss of food 

 than in others, and the completeness and economy with which this 

 separation of the fatty elements of the food is effected varies 

 according to the internal structure and organism of the animal 

 itself. Perhaps it is owing in part to the fact that one animal 

 masticates, and grinds up, and digests its food more perfectly 

 than another. 



Milk is secreted from the blood. If the blood is thin and 

 poor and but slightly charged with the rich elements taken up 

 in the food, the milk is of necessity poor and watery, and the 

 quality will usually bear an intimate relation to the quantity 

 produced. If the organization of two animals is such that they 

 separate or eliminate the fatty elements of the food and store it 

 away in the blood equally well, they accomplish the first step in 

 the process of conversion of food with equal economy, and, so far 

 as this goes, it is the same whether the subsequent use to be 



