Pepsin, pure, 128 grains.

Simple elixir, 16 fluidounces.

Acetic acid, 2 fluidrachms.

Mix them together and shake occasionally during a period of not less than twenty-four hours. Do not filter unless absolutely necessary. The acid usually employed to effect the solution of pepsin (hydrochloric acid) is substituted in this case by acetic acid. We do this in order to obtain a simple elixir of pepsin more compatible with certain iron salts and with ammonio-citrate of bismuth. Hydrochloric acid may be necessary in connection with pepsin to effect the artificial solution of coagulated albumen, but we are by no means convinced that it is a necessity when the pepsin is in the stomach. Indeed, the probabilities are that the gastric juice supplies the acid principle, even in very dyspeptic persons, and reports from those who use dry pepsin corroborate the inference.

Each fluidrachm (teaspoonful) of the finished elixir contains two grains of saccharated pepsin.

The formula first brought to our notice for elixir of pepsin appeared in the Druggists' Circular, 1869. Fresh rennet was employed, with salt, wine, and aromatics. The formula we present contains the proportion of pepsin recommended by the American Pharmaceutical Association, 1873.