A study to determine the effects of different types of vitamin D administration on young infants in St. Louis has been carried on for a period of twenty months, beginning in September 1937. The present report is confined to observations on the growth and development of the infants and on the incidence of rickets. Observations on the incidence of feeding difficulties, gastrointestinal disturbances and rashes will form the basis of a subsequent communication.
METHOD
Babies were selected from the wards of the St. Louis Maternity Hospital and the St. Louis City Hospital. They were normal, healthy infants weighing at least 5 pounds (2,268 Gm.) at birth, and the mothers were intelligent and willing to cooperate. Primiparas formed the largest part of the maternal group. Within a week after discharge from the hospital, each mother and child were visited by the trained nurse of the clinic. The nurse was capable and