Experiments on vitamin A

Abstract

These experiments relate chiefly to questions concerning the storage of vitamin A in the body and the bearing of this upon methods of examining foods to determine their relative richness in vitamin A.Even at weaning time young animals may already have a considerable store of vitamin A in the body and thus be able to continue to grow for some time upon a diet carefully freed from vitamin A but adequate in all other respects. Young rats separated from their mothers at a uniform “weaning” age of four weeks show very different growth curves and survival periods on the same experimental diet free from vitamin A, according to the vitamin A content of the mother's diet. The differing stores of vitamin A in the bodies of experimental animals, even at early ages, has undoubtedly been a very large factor, not fully appreciated, in previous experiments dealing with this vitamin and in attempts to determine the vitamin A content of different foods.The body can also store vitamin A at later ages. Thus two male rats of...