The infant should be given a teaspoonful of cool water to drink two or three times a day, as the milk does not quench the thirst.  The water should be sterilized by boiling, and be kept in an air-tight flask.

At the end of the third month the intervals of nursing for the daytime should be three hours, and the last nursing at night should be at eleven o’clock, and the first nursing in the morning at five o’clock; thus allowing the mother an interval of six hours of unbroken sleep.

The best evidence of the proper nutrition of the child is a progressive gain in weight.  The child should be weighed every week.  A loss of a few ounces usually takes place during the first few days after birth, so that the child does well if at the end of the first week it weighs as much as it did at birth.  After the first week the weekly gain should not fall below five ounces.

The Wet-nurse.—­ When the mother for any reason whatever is not able to nurse her child, the best substitute is a wet-nurse.  Before she is employed the wet-nurse should always be carefully examined by a physician to insure her freedom from disease.  The best age is between twenty and thirty years, and the age of the child of the nurse should be at least within a month of that of the child to be nursed.  The best sign of the good health of the nurse and of the condition of her milk is furnished by the health of her own child.  The breasts should be well formed and the nipple of good shape.  It is well, if possible, to get a woman who has borne several children, as she will understand the care of the child better.  No woman who is not perfectly healthy is fit to be a wet-nurse; and even after she has been engaged her health and her habits must be watched over.

Artificia1 Feeding.—­ The first requisite in artificial feeding is that the milk shall be made to correspond as nearly as possible to that of the mother.  For this purpose the following formula, prepared by Rotch, of modified cow’s milk is considered the best: 

Milk            2 ounces
Cream           3 ounces
Water           10 drams
Milk-sugar   6 3/4 drams
Lime-water       1 ounce

To make one pint of the mixture for use in the twenty-four hours, take the milk and cream as soon as it comes in the morning, and mix as above directed.

No less important than the correct proportions of the ingredients, is freedom from disease germs and bacteria of putrefaction.  Complete sterilization is possible by prolonged boiling; but experience has proved that under prolonged exposure to a temperature near the boiling-point certain changes take place in the albuminoids of the milk which greatly impair its digestibility.  Full sterilization of milk for infant feeding has therefore practically been abandoned.  It has been found that milk heated to 167° F. for twenty minutes, and promptly chilled by placing on ice, remains practically sterile for twenty-four hours, and it is spared the injurious changes which take place at a higher temperature.  This process is known as Pasteurization.  The Arnold steam sterilizer affords a convenient method of sterilizing; if used with the cover removed, the steam chamber being open, the temperature of the steam chamber does not exceed 170° F.