Abstract
1. The secretory response to stimulation of the vagus nerves has been examined in the pig and compared with that in the dog under similar experimental conditions.2. In the pig, stimulation of the vagus nerves caused a profuse flow of pancreatic juice with a high content of bicarbonate, in addition to a secretion of digestive enzymes; atropine suppressed the secretion of enzymes but failed to diminish the flow of bicarbonate-rich juice.3. Intra-arterial injections of acetylcholine closely imitated the effects of stimulation of the nerves, with the difference that both the flow of juice and the secretion of enzymes were abolished together by atropine.4. Stimulation of the nerves and injections of acetylcholine were effective after resection of the stomach and intestine: these stimuli can therefore act directly on the pancreas, independently of the release of gastro-intestinal hormones.5. In the dog, the pancreas differed from that of the pig in that stimulation of the vagus nerves and injections of acetylcholine acted predominantly on the secretion of enzymes and caused only a sparse flow of juice. Atropine annulled all these effects together.6. The results show that the vagus nerves can exert a much wider control of the secretion of pancreatic juice in the pig than in the dog. Possible mechanisms for this action are discussed.