In the following paper evidence has been brought forward to show how necessary it is that an infant should receive not only sufficient, but also proper, nourishment during the first year of its life. For not only is this necessity shown when we consider the results of improper feeding revealed by a study of the tables of infantile mortality, but also when we remember that a high infantile mortality rate means a high damaged life percentage, a circumstance of most serious import when affecting girls, who must be the mothers of the children of the future. The study of the composition of human milk must be the foundation of all our knowledge regarding the normal food of an infant. The variations to which human milk may be liable must be studied, the constituents of the milk investigated, and the effect on the infant of either an excess or diminution of the proteid, fat, and sugar, contained in that milk, determined. We shall then be in a position to consider the attributes of a perfect food, the influence which such a food exercises on the human economy, and to lay down some standard by which we can judge the various milk substitutes and foods, and compare our conclusions with the results obtained by actual clinical experience. Cow's milk and its modifications will also be discussed in regard to its suitability for infant feeding, also the various patent and proprietary foods. The necessity for breast feeding having been established, the various rules to be observed during that period, and the signs of successful feeding, will be indicated. The indications for weaning will be briefly stated, and the best methods of artificial feeding considered. Finally, the general conclusions of our investigations will be stated.