Previous studies from this laboratory, as well as elsewhere, have indicated that the antrum of the stomach is the chief or sole source of the gastric-secretion-stimulating hormone, gastrin. Complete excision of the gastric antrum in dogs practically abolishes the secretion of gastric juice from a vagusdenervated Heidenhain pouch.1 Exclusion of the antrum from the alimentary tract produces a similar reduction in secretion from the Heidenhain pouch, and this is restored if the antrum is replaced in its normal position or transplanted to the duodenum as a diverticulus. Transplantation of the antrum to the colon produces a marked hypersecretion of gastric juice from the Heidenhain pouch. On the other hand, transplantation of similar pouches fashioned from the corpus or fundus of the stomach into the duodenum or colon produces no stimulation of secretion.2 If the antrum is converted into a vagus-denervated isolated pouch in an animal also provided with