The transmission of vitamin A from parents to young in mammals

IN an earlier paper [Dann, 1932] a preliminary investigation of the factors controlling the transmission of vitamin A from mammalian mothers to their young was described, most of the work being done upon the rat. One of the conclusions reached, which is further examined in the present communication, was that " the amount of vitamin A in the liver of the foetal rat at birth is small and subject to little variation. It cannot be increased by giving large amounts of carotene to the mother before or during pregnancy." The provitamin A, carotene, was used in those experiments because at that time no rich concentrate of vita- min A was available in the quantities required. Since the publication of the earlier paper, however, concentrates of vitamin A have become available in large quantities, and it has been thought advisable to repeat the work upon the rat using vitamin A itself in the diet. The repetition (described below) led to a con- clusion similar to that reached from the earlier work, namely that the amount of vitamin A in the liver of the foetal rat remains small even when the parent doe receives large amounts of vitamin A before or during gestation.