=Top-Milk.=—When the milk has been standing at rest three or four hours, the top-milk will be considerably richer than the rest. If such rich milk is wanted for any particular purpose it may be poured off, to be eaten with cereals, berries, etc. In twelve hours most of the cream will rise and may be skimmed off, although thirty-six or even forty-eight hours may be required to get all that can be obtained by setting. The half-skimmed milk left when the top-milk has been removed after 3 to 6 hours’ setting will still contain 2% or more of butter-fat and is very good for drinking; even the skim milk from which the cream has been taken after 12 hours’ setting is still an excellent beverage, provided it is sweet. Perfectly skimmed, almost entirely fatless, milk may be used in various ways in cooking, to make up for lack of protein in many other food products. But care must be taken that it is pure and sweet, or rather, its condition, sweet or sour, must be under the perfect control of the housekeeper. If a sample of milk will stand scalding or even boiling without curdling, it is usually fresh and in good condition for any use. On the other hand, if it curdles by scalding, it is beyond control and it may or may not make good sour milk, depending on the bacteria working in it. MILK FOR INFANTS [Illustration] Comparing cow’s milk with mother’s milk, it will be seen that the latter contains less protein, about the same percentage of fat and more carbohydrates than the former. A comparison may be made from the following table of average composition in round figures: ──────────────┬───────┬───────┬───────┬───────┬───────┬───────┬─────── │ │ │ │ │ │ │ Fuel │ Water │ Total │Protein│ Fat │ Milk- │Mineral│ value │ │solids │ │ │ sugar │matters│per lb. ──────────────┼───────┼───────┼───────┼───────┼───────┼───────┼─────── │ Per │ Per │ Per │ Per │ Per │ Per │Calories │ cent │ cent │ cent │ cent │ cent │ cent │ ──────────────┼───────┼───────┼───────┼───────┼───────┼───────┼─────── Mother’s Milk │ 87 │ 13 │ 2 │ 4 │ 6.5 │ 0.5 │ 316 ──────────────┼───────┼───────┼───────┼───────┼───────┼───────┼─────── Cow’s Milk │ 87 │ 13 │ 3.25 │ 4 │ 5 │ 0.75 │ 312 ──────────────┴───────┴───────┴───────┴───────┴───────┴───────┴─────── =Modifying Milk.=—Undiluted cow’s milk is too rich in protein and in salts for infants and, when fed without modification, must be diluted with an equal amount of water during the first two or three months. Such dilution, however, also reduces the percentage of fat, which should remain the same, and of carbohydrates, which should be increased. In order to modify or “humanize” cow’s milk so as to make its composition nearly the same as that of mother’s milk, simple dilution with water is therefore not sufficient.