_Pasteurized Milk._ In pasteurizing milk the aim is to destroy as many of the bacteria as possible without causing any chemical changes or without changing the flavor. One can pasteurize milk at home by placing it in an air-tight bottle, immersing the bottle to the neck in hot water, heating the water to 167 F. for twenty minutes, and then quickly cooling the milk to 50 F. by immersing the bottle in cold water. The rapid cooling lessens the cooked taste. The best dairies pasteurize the milk before it is marketed. _Sterilized Milk._ Milk is sterilized to destroy all bacteria, by heating it to 212 F. Sterilized milk remains sweet longer than pasteurized milk, but more chemical changes are produced and the flavor is changed, resembling that of boiled milk. Formerly borax, boric acid, salicylic acid, formalin, and saltpeter were used to keep the milk sweet, but this adulteration is now forbidden by the pure-food laws. _Malted milk_ is a dry, soluble food product in powder form, derived from malted barley, wheat flour (dextrin), and cow’s milk, containing the full amount of cream. The process of the extraction from the cereals is conducted at elevated temperatures so as to allow the active agents (enzymes) of the barley malt to effect the conversion of the vegetable protein and starches. The filtered extract, containing the derivatives of the malt, wheat, and the full-cream cow’s milk, is then evaporated to dryness _in vacuo_, the temperature being controlled so as to obviate any alteration of the natural constituents of the ingredients and so as to preserve their full physiological values. The strictest precautions are observed to insure the purity of the product. It contains: Fats 8.75 Proteins 16.35 Dextrin 18.80 Lactose and Maltose 49.15 (Total Soluble Carbohydrates) 67.95 Inorganic Salts 3.86 Moisture 3.06 Malted milk is free from germs. The starches and sugars are converted in the process of manufacture into maltose, dextrin, and lactose. The fats are in an absorbable condition, and it contains a high percentage of proteins derived from both the milk and the grains, as well as a marked percentage of mineral salts. It is readily soluble in water and is easily digested. The hydrochloric acid of the stomach coagulates or curds milk much as it is curded by many fruit and vegetable acids, such as those in lemons or tomatoes. Thus the milk forms into curds immediately on entering the stomach, the casein being at once precipitated by the rennin. This is the chief reason why it should be drunk slowly, otherwise too large curds will form, causing distress from pressure. * * * * * [Sidenote: Digestion of Milk] A part of the digestion of the casein is performed by pepsin in the stomach and a part by the trypsin of the pancreatic juice.