In illustration of the influence of the FIRST condition. I may refer to the experiments already mentioned as having been made by Spallanzani, Stevens, and others, to shew the solvent power of the gastric juice on food even out of the body. Spallanzani states, that when small portions of well-masticated beef or mutton are placed in a vial with a due proportion of gastric juice, and the requisite temperature and gentle agitation are secured by placing the vial in the arm-pit, the appearances presented at the end of a few hours are extremely analogous to those observed in the natural process of chymification; the meat being in both cases converted into the soft greyish mass of a pultaceous consistence called chyme. Dr Beaumont, who was well aware of the importance of Spallanzani’s researches, and of the almost universal adoption of his views by succeeding physiologists till confidence in their accuracy was for a time shaken by the bold and fallacious assertions of Montégre, felt that the opportunity afforded him by St Martin’s wound for verifying or disproving the experiments on which these views were founded, was much too valuable to be lost. He therefore entered upon a long series of investigations, of which the following is an imperfect, though I hope instructive, abstract. To test the reality of the solvent powers ascribed to the gastric juice, Dr Beaumont withdrew from St Martin’s stomach about one ounce of it, obtained after a seventeen hours’ fast, by introducing first a thermometer to induce the secretion, and then a gum-elastic tube to carry it off. Into this quantity, placed in a vial, he introduced a piece of _boiled recently-salted beef_, weighing three drachms. He then corked the vial tightly, and immersed it in water raised to the temperature of 100°, which he had previously ascertained to be the heat of the stomach when the secretion was going on. In _forty minutes_, digestion had distinctly commenced on the surface of the beef. In _fifty minutes_, the fluid became quite opaque and cloudy, and the texture of the beef began to loosen and separate. In _sixty minutes_, chyme began to be formed. In _one hour and a half_, the muscular fibres hung loose and unconnected, and floated about in shreds. In _three hours_, they had diminished about one-half. In _five hours_, only a few remained undissolved. In _seven hours_, the muscular texture was no longer apparent; and in _nine hours_ the solution was completed.