The newborn infant has a store of iron already on hand, derived from the mother through the placenta before birth. After the birth, and through the nursing period, the child receives a certain amount of iron from the mother's milk. This supply is not altogether reliable, however, since any disturbance of the digestion will tend to interfere with its absorption, and consequently deprive the organism of what would otherwise be used for the building up of the blood supply. Thus it is clearly indicated that the infant's safest source of iron is from the mother during the pre-natal period. This supply must necessarily come from her diet during this time, and is made possible by regulating day by day the iron bearing foods in her dietary. After the original store of iron is reduced to that of the adult (after the child has tripled in birth-weight, generally at 12 or 13 months), and during the remainder of the growth period, it is very necessary to regulate the iron-bearing food in the diet, in order to insure the child of an adequate amount to cover the demands made by the increasing blood supply. VITAMINES Up to a few years ago it was believed a complete diet should contain an adequate amount of protein of a proper type, a sufficient amount of calcium, phosphorus and iron, and enough carbohydrates and fats to furnish the body with sufficient fuel to cover its energy expenditures. This belief was proved to be incorrect a number of years ago by Dr. Hopkins of England. In making certain feeding experiments with rats, Dr. Hopkins showed that some substance or substances present in milk, other than those already mentioned, was essential for the growth of the animal; that animals deprived of this material grew for a time, but gradually ceased to do so. Later on, Osborne, Mendel, McCollum and Davis discovered a like substance in butter fat; and still later Dr. McCollum found the same growth stimulating material, or one very like it, existing in the leaves of plants. These scientists found, upon investigation, that there were probably two substances in milk--one soluble in the fat, the other in the protein-free and fat-free whey--both of which were essential for normal growth. In 1911 Dr. Funk discovered in rice polishings a substance which he believed to be a cure and preventive of Beri-beri; to this substance, which is now believed to be identical with the second substance found in milk, he gave the name "vitamine." Dr. Funk's name "Vitamine" is now accepted to cover a number of substances essential to growth, and for the prevention and cure of certain diseases. To the first two has been added a third member of the vitamine family, which has proved to be a cure and preventive of scurvy. These substances are called--on account of the substances in which they are soluble--"Fat soluble A," "Water soluble B," and "Water soluble C." The table on page 496 shows the sources from which these factors may be obtained. The four plus system is used by Dr. Eddy to