Weaning is rendered easier by selecting a nursing-bottle which has the nipple in the shape of the breast. Care should be taken that the hole in the nipple is not too large, supplying more milk than the stomach can take care of as it comes, and so causing stomachic disorder. The nursing bottle should at all times be kept thoroughly clean by rinsing in hot water and washing in hot soapsuds. The milk for the child's bottle should, wherever possible, be what is called "certified," that is, the milk from a herd of cows which have been declared by the proper authorities to be all in good health, and which have been milked under sanitary conditions. This milk is delivered in clean, sealed bottles, preventing the admission of any dirt or deleterious substance from the time it leaves the dairy till opened. The milk for the baby should not be purchased from the can. Milk that has been sterilized, that is, bottled and put in boiling water for an hour, is not so good for the baby as pasteurized milk; that is, milk kept at something less than the boiling point for half an hour, since the higher temperature causes the milk to lose some of the qualities beneficial to the child. Since cow's milk differs in its constituents from mother's, having more fat and less sugar, there will be need at first to modify the cow's milk, weakening and sweetening it somewhat. One good recipe for modifying cows' milk is: One part milk, two parts cream, two parts lime-water, three parts sugar water, the sugar water being made by putting two even teaspoonfuls of sugar of milk in a pint of water. Condensed milk, which is often used as a substitute for cows' milk, is not nearly so good, since it has lost in the process of condensation one of the most important elements, that which forms bone tissue. Accordingly, babies fed upon condensed milk are apt to be "rickety," and they lack in general power to resist disease, which is primarily the mark of a baby fed on mother's milk, and to a slightly lesser degree, one fed upon cows' milk. The stomach grows very rapidly during infancy, increasing from a capacity of one ounce soon after birth to eight ounces at the end of the year, and this should be taken into account by the increase of the amount supplied it. After the first week, a baby should increase in weight at the rate of one pound a month for the first six months. If he falls behind this rate and remains healthy, more sugar and fat may be introduced into his milk. If, however, he fails to gain weight and is sickly, the milk should be diluted and modified so as to make it easier of digestion.