I. Chicks were reared in germ-free and conventional environments on diets devoid of one of each of the following vitamins: riboflavine, pantothenic acid, vitamin Be, vitamin B,,, folic acid, nicotinic acid, thiamine or biotin. When marked signs of deficiency began to appear the birds were killed. The livers and caecal contents were removed and assayed microbiologically for the vitamin omitted f...
