The Relation of Cholesterol to Vitamin D

IN continuation of our work on the molecular groupings essential for the successful activation of sterols by ultraviolet light [Rosenheim and Webster, 1926] we had the privilege of collaborating with Prof. Windaus of G6ttingen in the examination of various isomers of cholesterol, recently prepared by him, and of other sterols. The details of this work which gave entirely negative results [see also Hess and Windaus, 1926] we hope to publish shortly in con- junction with Prof. Windaus.