To the action of vitamin D. Kreitmair and Moll (Münch. med. Woch., 1928, No. 15)

While most hormones are known to cause poisoning in humans and animals in large doses, vitamins, which also show their specific action in the smallest doses, were previously considered quite harmless. Since it has been discovered that vitamin D is nothing more than ergosterol activated by ultraviolet rays, it has been possible to manufacture this vitamin in unlimited large quantities and to check experimentally the question of hypervitaminosis.