Not only is the greatest care taken that the milk used shall be pure and sterilized ready for use, but these laboratories are equipped by special machinery which separates the important elements of the milk-- namely, the fat, the milk-sugar, and the proteids. So that the physician can modify the proportions of these various ingredients of the milk to meet the necessity of the age and requirements of the infant. When the milk contains too little sugar, the infant does not gain as rapidly in weight as it would otherwise do. Too much sugar in the milk is indicated by colic, thin, green, or acid stools, or eructations of gas from the stomach. An excess of fat in the milk is indicated by vomiting; too little fat causes constipation with dry hard stools. Proteids in excess are a prolific cause of colic and also of diarrhea. Prescription blanks are furnished the physician, who fills out the percentages of fat, milk-sugar, proteids, and alkalinity, to suit the age, weight, and general condition of the child. He orders also the amount to be given at each feeding, and the number of feedings to be given in the twenty-four hours. Each bottle contains just the amount to be given at one feeding. All that the mother needs to do is to place the bottle in a receptacle containing warm water, until the milk has attained a temperature of 99∞ F., remove the cotton stopper, and put on the nipple, when it is ready for use. The Nursing Bottle.-- This should be of clear glass, with a rounded bottom, and of such a shape as is easy to clean; so that no particles will cling around a corner which cannot be reached. The graduated bottle is the most convenient, as it enables the quantities of each of the materials used in the preparation of the feeding to be mixed in the bottle, doing away with the trouble of measuring before putting into the bottle. Rubber Nipples.-- Two nipples should be kept for alternate use, and no nipple should be used longer than two weeks. A soft rubber of conical shape is best, with an opening at the top which is not too large, so that the milk will not flow through, as it is desirable that the child should obtain the milk by suction. So soon as the feeding is over, the nipple should be removed from the bottle, and brushed on both sides with a stiff brush. It should then be put in cold water, where it is kept until it is again wanted. The baby should be fed slowly, from ten to twenty minutes being taken for each feeding. Sucking from an empty bottle or with a nipple in the mouth should never be permitted, as in this way the baby draws air into its stomach, which will result in colic. Each flask should contain only enough for one feeding.