The accumulation of antibodies in the stomach contents of foetal rabbits.

Antibodies can be detected in the amniotic fluid and in stomach contents of rabbit foetuses exposed to immune serum following injection into the uterine lumen or into the maternal circulation. It is shown that the positive reactions obtained with foetal stomach contents were due to the presence of specific antibodies derived from the immune sera to which the foetuses were exposed. By means of injections of immune rabbit and bovine sera into the embryonic membranes of 24-day rabbit foetuses, it was demonstrated that the antibodies in the stomach contents are derived from the amniotic fluid and not from the foetal circulation. There is a pronounced tendency for antibodies to be concentrated in the stomach, concen­trations of 32 and 64 times the titre of the amniotic fluid being observed. Although anti­bodies of rabbit origin readily pass through the yolk-sac splanchnopleur into the foetal circulation, they do not do so through the stomach wall in detectable amounts.