Prior to the introduction of insulin, diabetes mellitus in children ran a rapidly progressive course, often proving fatal within six months after the symptoms had become sufficient to lead to a correct diagnosis. With rigid dietetic treatment and intelligent care, it was occasionally possible to prolong the life of the older children for two or three years. However, the diet on which life was sustained was inadequate for normal growth and development in these children. Consequently, the typical diabetic child on dietetic treatment in the preinsulin days was much undernourished and stunted in growth, if the mildness of his disease permitted his survival. Insulin has revolutionized the treatment of diabetes in patients of every age, but the most striking and encouraging results have been obtained in the treatment of the disease in children. Now it is possible to supply the immediate metabolic requirements of these children so that they not