Modern science has discovered no better food for infants than mother’s milk, and no substitute more satisfactory in general than suitably modified cow’s or goat’s milk. Under modern conditions of life, particularly in cities where milk has to be transported over long distances, and where much time necessarily elapses before the milk can be placed in the hands of the consumer, there is serious danger of contamination of the milk with disease germs. In all enlightened communities this danger is fully recognized, and the entire milk supply, so far as possible, but that part of it destined for the feeding of children in particular, is safeguarded by all available means. A fairly reliable index to the degree of enlightenment of any community is the quality of the milk which its children receive. One recent discovery of considerable importance, and incidentally an interesting illustration of the way in which correct procedure may be hit upon in advance of the scientific knowledge which justifies it, is the finding that orange juice contains one of the dietary accessories, known as vitamines, essential to health, and present in raw milk, but destroyed when milk is heated. For years, physicians had recommended orange juice for babies. It is of vital importance when the milk must be pasteurized. Both the heartbeat and the breathing in the young child are much more rapid than in the grown person. It is believed that this quickness of heart action and of breathing rate are related to the smaller size of the infant as compared with the adult and are of no very marked significance. At any rate it is true in general that the smaller the animal the more rapidly does its heart beat and the more quickly does it breathe. A very noticeable fact about young children is the susceptibility to all sorts of influences of the mechanism by which the breathing is controlled. Every passing interest reflects itself in heightened breathing. Violent emotion often leads to such extreme overbreathing as to drain the child’s blood of considerable of its store of carbon dioxide, whereupon the rapid breathing gives place to prolonged holding of the breath. Many a young mother has been seriously alarmed by the length of time her offspring in a tantrum is able to refrain from drawing its breath. Contrary to the appearance of things, which would indicate that the child is holding its breath out of spite, and in the hope of getting even with its parent, the cessation of breathing is largely or wholly automatic, indicating the way in which nervous and chemical influences have interacted to suspend the respiration.