The external secretion of the pancreas after a radical operation of stomach cancer with complete removal of the regional lymphnodes was studied in dogs with following results. 1. Cutting the coeliac nerves or the coeliac and vagus nerves was followed by decrease of external secretion of the pancreas and the absence of effects of insulin which should promote external secretion of the pancreas. But 2 months or less after the operation it was normally secreted and insulin injection normally promoted its secretion. 2. Cutting autonomic nerves did not affect the volume of pancreatic juice secreted in response to the soap in the jejunum. 3. It is considerd that the humoral mechanism of external secretion of tho pancreas normally exists after cutting autonomic nerves, while the control of these nerves is lost, and the mechanism of nevous control recovers its normal function 2 months at most after the operation.