In June, 1924, it was announced by Hess, and in September of the same year by Steenbock, that inert substances can be endowed with antirachitic potency by means of ultraviolet irradiation.1 Less than two years later, Windaus and Hess2 and Rosenheim and Webster3 shed further light on this subject by showing that it is ergosterol which undergoes this remarkable metamorphosis. During the short period which has followed, much has been learned and the advance has been steady and significant, but this aspect of pharmacology is so novel that it is not surprising that much remains to be explored and elucidated.
As is true of nutritional disorders in general, so of rickets the most important realm of therapeutics is that of prevention. With this goal in view we attempted the absolute prevention of rickets in sixty infants, from 4 to 12 months of age, by giving, in the