MORPPIOLOGY OF MILK. 375 



It also teaches that inheritance is a force as uniform in its 

 action, and as invariable, as is the law of gravity; like grav- 

 ity, its action is modified and interfered with by opposing 

 forces which disguise oftentimes its phenomena. As gravity 

 acts alike on the feather and the bullet, so does inheritance 

 act alike on all animals. In vitality, we have such a com- 

 plexity of phenomena that a right interpretation is oftentimes 

 difficult, if not impossible ; yet the grand law of inheritance, 

 the propagation of qualities possessed by ancestors, may be 

 disguised in individuals, but cannot be denied to the race. 



It is to this universal law of inheritance, as modified by 

 other laws, the resultant of whose forces is the animal form, 

 that we are to seek the explanation of the variations that occur 

 between members of the same species, breeds, families and 

 individuals. 



Those features of animal form, that are readily cognizable 

 are usually more changed by the breeders' art than other fea- 

 tures which are not so readily noted. Consequently, the 

 grazing-breeds have been brought to a greater uniformity and 

 perfection than have the dairy-breeds, as the changes to be 

 desired have been more clearly indicated in the beginning 

 and recognized in the achievement. Changes in the dairy- 

 breeds are to be understandingly brought about by breeders 

 and farmers who have a practical belief in the universality of 

 law — that inheritance of form is not more important in modi- 

 fying the shape of body, than it is in determining the products 

 from the animal. 



Whether a cow's milk is better fitted for the making of 

 butter or cheese, or for any other purpose, is largely deter- 

 mined by inheritance, as is also the amount she will give ; the 

 manner in which she will give it ; the economy with which 

 she will produce it from her food, and the effect of the pro- 

 duction upon the health of the animal. 



Milk is the product of the mammary gland, and is a fluid 

 intended for the nourishment of the infant animal. It con- 

 tains, therefore, all the elements needed for nutrition and 

 growth ; chemically, is a perfect food ; in practice, will sup- 

 port life from infancy to maturity. 



In composition it varies greatly in the amount of its proxi- 

 mate constituents, dependent somewhat on the individual cow, 



