The act of vomiting in man.

The mechanism of vomiting in mammals is highly complex, and some aspects of it are not well under-stood despite the many experimental studies which have been made, particularly in cats and dogs. For example, there is still room for debate about the gastric and intestinal movements during nausea, about the role of the stomach in vomiting, and about the mechanism of opening of the cardia. The reported studies of the act of vomiting in man are comparatively few. Most of these were fluoro-scopic studies of persons vomiting after a bismuth or barium meal and were made many years ago with x-ray apparatus which would today be regarded as primitive. It was unsuitable for taking radiographs during the act because the long exposure times would