The food of many very young infants is cow's milk, although there is wide agreement among pediatricians that human milk is preferable. However, since the latter often is not supplied, it would be highly desirable to be able to modify cow's milk to provide a formula more nearly comparable to human milk in composition. The papers of this series present a comprehensive picture of the vitamin contents of human and bovine milks. Any approach to the problem of modifying cow's milk so that the formula will be a more adequate substitute for the food Nature intended must be based on a thorough knowledge of the composition of these two sources of infant nourishment.
In comparing the milks secreted by the cow and the human being, certain species differences should be borne in mind. The cow has been bred for many generations with the objective of obtaining animals which will produce