The Oxidative Destruction of Vitamins a and E

It is generally accepted that vitamin A as found in butter fat and cod liver oil is easily destroyed. Heating and aerating these fats for a short time or exposing them to air at room temperature for a longer period uusually deprives them of every trace of vitamin A. During such treatment the fats absorb oxygen and a long series of partial oxidation products is recognized as accompanying the more or less undefined condition of rancidity so developed. A destruction of vitamin E as found in butter fat was first indicated by our experiments 1 on milk rations. These showed that 50 per cent of whole milk powder supplemented with 8 per cent of casein, 2 per cent of mineral salts, 5 per cent of yeast and 35 per cent of starch was adequate for growth and reproduction of rats, but that when appreciable quantities of lard, from 15 to