Milk is prepared by predigestion with pepsin (peptonizing), or with pancreatin (pancreatinizing). Milk is peptonized by adding some powdered pepsin, or solution of pepsin, to fresh milk slightly acidulated (hydrochloric acid); or it is pancreatin-ized by adding pancreatic extract or solution of pancreatin to the fresh milk, with sodium bicarbonate (fifteen grains of the sodium bicarbonate to the pint).

Milk is preserved by the method of sterilization, or Pasteurization. Milk, heated up to the boiling point—to 212° Fahr.—becomes sterile because all ferments or organisms are inhibited or destroyed at that temperature. To accomplish this result, the milk in bottles or jars is placed in steam chambers, the temperature of which is, of course, at 212° Fahr. Such milk has, however, the taste of boiled milk, and various changes occur in it in consequence of which the casein is less digestible in the juices of the stomach and intestines, the emulsioniz-ing and absorption of the fat is rendered slower, and, according to Leeds, the amylolytic ferment is destroyed. If the milk is allowed to remain too long at 212° Fahr. the lactose is converted in part into caramel, whence the milk assumes a brownish hue.

Pasteurized milk is prepared by raising the temperature of the milk for fifteen to twenty minutes to 160° or 170° Fahr. The bottles containing the milk are immersed for the required period in water at the temperature named. The milk so prepared is but little changed, but it will keep for a day or two only.

Condensed milk has been briefly referred to, but some further details are necessary, since this has become an important food for infants and various invalids. Milk is condensed by depriving it of its water by means of slow and moderate heat in vacuo. The varieties of condensed milk are due to differences in the mode of preparation. All the water evaporated, and the residue mixed with a large (60 to 75) percentage of sugar, a dry granular mixture results. The usual form is a soft solid about the consistence of honey, and containing 30 to 45 per cent of sugar. Swiss condensed milk is a mixture of cow's and goat's milk. One form is evaporated by sufficient heat to render it aseptic, and no sugar is required. Put while hot in cans and hermetically sealed it remains fresh for months—even years.

Condensed cream is a product like condensed milk, and is a mixture of milk and cream.

Humanized milk is a preparation of cow's milk made in imitation of human. The preparation of Meigs is a good one; it is as follows:

Cream...........................................   2 tablespoonfuls.

Milk.............................................   1 tablespoonful.

Lime-water.......................................   2 tablespoonfuls.

Water...........................................   3 tablespoonfuls.

Milk sugar.......................................   1/2 teaspoonful.