The occurrence and characters of the secretion are described. Atropine sulphate (gr. 1/100) depresses this secretion in greater or less degree; larger doses (gr. 1/50-1/25) inhibit it completely by paralysis of the vagal endings. The fasting secretion is probably identical with the "psychical secretion" of Pavlov; secretion occurring during inhibition of the fasting secretion corresponds to the "chemical secretion." The diminution in gastric acidity after atropine is due to (a) inhibition of fasting secretion. (b) facilitation of duodenal regurgitation, with neutralization of acid. The relation between the chloride and acidity curves is discussed, and arguments adduced in favor of a secretion of neutral chloride by the stomach. Evidence of incomplete mixing of the stomach contents is advanced, though the differences in composition of samples withdrawn simultaneously from various parts of the stomach are not as a rule sufficient to invalidate the test-meal results.