This investigation was undertaken for the purpose of determining the amount of irradiated dry yeast necessary for the cure of rickets in children and of making a comparison of the antirachitic potency of such yeast with that of cod liver oil by means of clinical findings. Yeast, which is one of the richest known sources of ergosterol, is easily given antirachitic potency by means of exposure to ultraviolet rays. This study was carried out experimentally by Hess and his collaborators1 in 1924, and although the products yielded encouraging results in the preliminary tests the therapeutic uses of irradiated yeast have not been clinically determined. Its advantages appear to be its relative cheapness and the ease with which it may be administered, on account of both its consistency and its flavor.
Few clinical tests of irradiated yeast have been made. Kon and Mayzner2 in Warsaw, Poland, carried out a