1. The gastric and intestinal phases of gastric secretions were selectively evoked before and after the removal of the antral mucosa in four dogs provided with a special cannula that allowed complete separation of the stomach and duodenum without interrupting neural connexions between them. 2. The gastric phase induced by 5% liver extract meal administered into the stomach at various distension pressures (ranging from 0 to 15cm H2O) resulted in an increase in acid output to about 56% of the histamine maximum and in a marked rise in serum gastrin. 3. Following resection of the antral mucosa, the gastric acid response to meal of liver extract was reduced by about 50% and serum gastrin response was completely eliminated. Exogenous gastrin (G-17) given during the gastric phase induced by such a meal in dogs with antral mucosectomy failed to restore acid output to pre-resection level. 4. Intestinal perfusion of meal of liver extract in graded amounts stimulated gastric acid secretion to about 30% of histamine maximum acid output and raised significantly serum gastrin level. 5. Antral mucosectomy abolished almost completely both gastric acid and serum gastrin response to intestinal meal of liver extract. 6. Exogenous gastrin given during the intestinal meal of liver extract failed to restore acid output to the pre-resection level, suggesting that this procedure greatly reduced the secretory capacity of the oxyntic glands. 7. We conclude that the antral gland area plays an important role in the gastric phase and that it is a prerequisite for the intestinal phase of gastric secretion.