{Butter. } {Cream. {Butter-milk.} Water. Milk. { {Buttery and cheesy residuum.} {Skimmed milk. {Curd. {Sugar of milk. } Pure {Whey. {Salts. } water. It may be stated, in other words, that milk is composed chiefly of caseine, or curd, which gives it its strength, and from which cheese is made; a butyraceous or oily substance, which gives it its richness; a sugar of milk, to which it owes its sweetness, and a watery substance, which makes it refreshing as a beverage; together with traces of alkaline salts, from whence are derived its flavor and medicinal properties; and that these constituents appear in proportions which vary in different specimens, according to the breed of the animal, the food, the length of time after parturition, etc. Milk becomes sour, on standing exposed to a warm atmosphere, by the change of its sugar of milk into an acid known as lactic acid; and it is owing to this sugar, and the chemical changes to which it gives rise, that milk is susceptible of undergoing all degrees of fermentation, and of being made into a fermented and palatable but intoxicating liquor, which, by distillation, produces pure alcohol. This liquor is extensively used in some countries. The arrack of the Arabs is sometimes made from camel’s milk. The Tartars make most of their spirituous liquors from milk; and for this purpose they prefer mare’s milk, on account of its larger percentage of sugar, which causes a greater and more active fermentation. The liquor made from it is termed milk-wine, or khoumese. It resembles beer, and has intoxicating qualities. The process of manufacture is very simple. The milk, being allowed first to turn sour, is then heated to the proper temperature, when it begins to ferment; and in a day in summer, or two or three days in winter, the process is completed, and the liquor may be kept several weeks without losing its good qualities. The admirable though complicated organization of the udder and teats of the cow has already been explained, in speaking of the manner of milking. But it may be said, in general, that the number of stomachs or powerful digestive organs of the ruminants is wonderfully adapted to promote the largest secretions of every kind. The udder of the cow, the more immediate and important receptacle of milk, and in which other milk-vessels terminate, is divided into two sections, and each of these sections is subdivided into two others, making four divisions, each constituting in itself, to some extent, an organ of secretion. But it is well known that, as a general thing, the lateral section, comprising the two hind teats, usually secretes larger quantities of milk than the front section, and that its development, both external and internal, is usually the greatest.