To compare the progress of digestion in the natural way with these results, Dr Beaumont, at the time of commencing the experiment just described, suspended a piece of the same beef, of equal weight and size, within the stomach by means of a string. At the end of the _first half hour_ it presented the same appearances as the piece in the vial; but when Dr Beaumont drew out the string at the end of _an hour and a half_, the beef had been completely digested and disappeared, making a difference of result in point of time of nearly seven hours. In both, the solution began on the surface, and agitation accelerated its progress by removing the external coating of chyme as fast as it was formed. When the experiment was repeated with chicken instead of beef, the solution was slower, from the greater compactness of the chicken not allowing the gastric fluid to penetrate its substance so readily. Had the beef and chicken been masticated before being subjected to experiment, the difference between them in the rapidity of digestion would probably have been less. To ascertain still more accurately the difference between _natural_ and _artificial_ digestion (the one _in_ and the other _out_ of the stomach), Dr Beaumont put twelve drachms of _recently-salted boiled beef_ into a vial, with the same number of drachms of fresh gastric juice obtained through the opening of the stomach after a fast of eighteen hours; and then placed the vial in a basin of water on a sand-bath, where he kept it at the heat of 100° Fahr., and continued to agitate it gently. Digestion soon commenced and went on uniformly for about six hours, when it ceased. One-half of the meat was then dissolved, and the texture of the remainder loosened and tender,--resembling the same kind of aliment when ejected from the stomach partly digested some hours after a meal, as frequently seen in cases of indigestion. On weighing the undissolved portion which remained after all action had ceased, six drachms and twelve grains of the beef were found to have been digested by twelve drachms, or nearly double its weight, of gastric juice. It thus appears that a given quantity of gastric fluid can digest only a relative proportion of meat; so that, when more is eaten than what there is juice sufficient to dissolve, stomachic disorder must necessarily follow. In this latter case, Dr Beaumont found that _the addition of fresh juice causes digestion to be resumed_.