The response of the cardia to section and stimulation of nerves and to the adm. of autonomic drugs was studied in 53 barbitalized dogs. Stimulation of the cervical vagus causes relaxation of the cardia, followed by contraction. The fibers producing contraction are cho-linergic, they travel in the main trunks of the vagus nerve. The inhibitory mechanism is within the wall of the lower esophagus. Two possible hypotheses are discussed as to the nature of this inhibitory mechanism. Interference with this inhibitory mechanism by bilateral vagotomy in the neck is followed by cardiospasm due to predominance of the sympathetic which is motor in its effect on the cardia. Ergot-amine causes relaxation of the cardia.