The proteid of milk is composed of lactalbumin and caseinogen. Lactalbumin is soluble in water, and as there is a larger percentage of this constituent in human than in cow's milk, the former during digestion forms into succulent curds; while the latter, containing more caseinogen, forms into dense cheesy curds.
Cow's milk, to form a typical infant food, needs to be modified. In many large cities throughout the United States, laboratories, with accompanying farms in outlaying districts, have been established to furnish proper infants' food. While human milk is self-modifying, thus meeting the needs of the child in the different stages of its growth and development, its composition varies but little during the period of lactation.
The modification of laboratory milk needs to be changed from time to time according to a physician's formula, lime-water being added to neutralize the acid present in cow's milk. Human milk is sterile, while cow's milk, in the hands of the consumer, contains many varieties of bacteria; therefore it was formerly thought advisable to sterilize the modified product; but sterilization has been largely superseded by pasteurization, and this is not deemed necessary or advisable, where fresh milk can be procured from a reliable source, except in cases of bowel trouble or in extremely hot weather.
A child should not remain at the breast for more than fifteen or twenty minutes at each feeding. Never wake a healthy baby during the night for feeding. It is sometimes necessary during the day, as a young child is quite liable to turn night into day; but by persistent effort this may be overcome before it is an established habit.
If for any reason the mother is unable to nurse her child, she must make a decision between a wet nurse and artificial feeding. Cow's milk is best adapted for artificial infant feeding, although in its composition it is not as nearly like human milk as the asses' or the mare's. Cows can be kept more easily under strict control than most animals, and when carefully stabled, fed, watered, and
