If the baby is not being adequately nourished, he will present exactly the opposite picture, in some or all of these respects. He will be unwilling to stop nursing after the normal length of time and will give evidence of being not satisfied when taken from the breast. He may be listless and fretful and sleep badly. He will not gain weight as he should and he may vomit or have colic after nursing. To ascertain whether or not such a baby is getting enough milk it is customary to weigh him, without undressing him, before and after each nursing. Each fluid ounce of milk will increase his weight one ounce. If the baby is not obtaining a normal amount of milk at each nursing, he is often given enough modified milk after each meal to supply the shortage, but at the same time an effort is made to increase the supply of breast milk by improving the mother’s personal hygiene, as described in Chapter IX. The amount which the baby needs at each feeding varies, not only according to his weight and age, but also according to his vigor and activity and therefore must be estimated for each baby. A very general estimate of the amount taken by the average, well baby at each feeding, is about as follows: First week 1½ to 2½ ounces Second and third week 2 to 4 ounces Fourth to ninth week 3 to 4½ ounces Tenth week to fifth month 3½ to 5 ounces Fifth to seventh month 4½ to 6½ ounces Seventh to twelfth month 6½ to 9 ounces =Artificial Feeding.= There is no entirely adequate substitute for satisfactory maternal nursing, and any other food that is given to the young baby is at best a makeshift. Considering the baby’s delicacy, therefore, and his urgent needs, no pains should be spared to make any artificial food that is given to him, as satisfactory as possible. And no matter what it costs, he should have only the freshest, cleanest and purest milk that can be bought. In preparing and giving artificial food it must be borne in mind that normal breast milk has the following characteristics: 1. It is exactly right in quantity, quality and proportion. 2. It is fresh, clean and sweet. 3. It is free from bacteria. 4. It tends to protect the baby from infection. 5. It definitely protects him from certain nutritional diseases. Cows’ milk, suitably modified, is apparently the best available substitute for mother’s milk, but it must first meet certain requirements and then be handled with scrupulous cleanliness and care, if it is to be satisfactory. The requirements are that the milk shall be: 1. Whole milk. It must not be altered by the removal of cream nor the addition of such preservatives as salicylic acid, formaldehyde or boracic acid. 2. Its composition must not vary greatly from day to day.