ConclusionsExtensive gastric resection (75%) in dogs when accompanied by a long afferent duodenojejunal loop is followed by a high incidence of spontaneous gastrojejunal ulcer. When histamine in beeswax is administered to such dogs, stomal ulcer occurs regularly. When gastro-intestinal continuity is reestablished by a short afferent duodenal loop in the Billroth II plan of operation, stomal ulcer after extensive gastric resection (75%) can not be provoked even when histamine in beeswax is administered.It is obvious that a short afferent duodenal loop is an important component of a satisfactory operation when gastric resection on the Billroth II plan of operation is invoked in the surgical treatment of ulcer.