In the autumn of 1895 I received from Professor M'Ewen several samples of gastric juice marked “Chalmers' Gastrostomy.” The samples were obtained under most favourable circumstances, being drawn off through an aperture made in the abdomen and stomach of the patient; the juice was almost pure, and nearly free from suspended matter. My analysis was mainly directed towards ascertaining whether or not free hydrochloric acid was a constituent of the fluid, and the following were the reactions I employed:—

(1) With methyl violet the sample gave a distinct blue coloration, showing the presence of a mineral acid. Supposing the acidity to be due to lactic acid, this reaction would not take place, as on trying a dilute solution of lactic acid with this reagent no blue colour was produced.

(2) On treating an alcoholic solution of phloroglucin and vanillin (1 grm. of the former and ½ grm. of the latter made up with 50 cc.'s rectified spirits) with the gastric juice and evaporating slowly on a water-bath, a red colour was produced. Dilute hydrochloric acid gave the same result; lactic acid none.

In the opinion of some authorities the presence of free hydrochloric acid is attributed to the decomposition on evaporation of the chlorides present in the gastric juice by free lactic acid. With a view to ascertain whether this could happen or not, I evaporated solutions of chloride of calcium and lactic acid with both of the above reagents with a negative result.