Transfer of proteins from the yolk to the chick embryo.

Abstract

THE transfer of antibodies from the mother to the fœtus in certain mammals, and from the hen to the egg yolk and thence to the embryo in birds, is well established. Whether proteins other than antibodies are thus transferred is still open to question. Despite our lack of knowledge on this topic, it is generally thought, as Buxton1 recently pointed out, that proteins pass from the blood or tissues of the hen as hydrolytic products which are reassembled into proteins within the ovum. Because of the proteolytic activity of the yolk sac and its contents, a similar mechanism is supposed to account for the passage of protein from the yolk into the circulation of the embryo.