VOMITING OF PREGNANCY

The antiperistaltic contractions of the stomach play only a secondary role in the mechanism of vomiting; the expulsion of matter is the result of the energetic compression of the stomach due to contraction of the abdominal muscles. Magendie demonstrated this with his well known experiment in which he provoked vomiting with an intravenous injection of an emetic in an animal whose stomach had been removed and a bladder used in its place.