CALCIFICATION OF THE TWORT MOUSE CARCINOMA (IN VIVO) BY MEANS OF VIOSTEROL

Although great strides have been made in the knowledge concerning calcium metabolism during the last decade, many things connected with it remain unexplained. Studies have been greatly stimulated by the discovery of a concentrated form of vitamin D in irradiated ergosterol, the preparation of a potent parathyroid extract and the biologic action of ultraviolet rays. Careful chemical studies and admirable dietary regimens have added much to previous information. Even such a substance apparently so far removed from the problem as lead has, in the expert hands of Aub, his co-workers,¹ and others, yielded facts of much value in its relation to calcium metabolism. However, in the present study we are concerned only with the first mentioned agent, namely, viosterol. Summaries of the present knowledge on this subject may be found in readable form in Cantarow's monograph on calcium² and in Peters and Van Slyke's excellent textbook on quantitative