---

• n  a fat-soluble vitamin that prevents rickets

• Abbott Laboratories of Chicago and Parke, Davis fortified A-rich halibut liver oil with viosterol (a concentrated Vitamin D), called the product haliver (portmanteau for halibut .
• No amount of cod-liver oil, viosterol, ultraviolet light or sunlight improved their condition.
• At Philadelphia Alfred Fabian Hess of Manhattan and associates advised milk from cows fed with irradiated yeast or viosterol as an excellent general preventive.

• vitamin D
• calciferol
• ergocalciferol
• cholecalciferol
• D