In conformity with this view, Dr Beaumont mentions, that, when St Martin swallowed a mouthful of any tenacious food after the digestion of the preceding meal was considerably advanced, he always saw it first pass towards the great curvature of the stomach, and then disappear. In a minute or two it re-appeared, more or less broken down, and _mixed with the general alimentary mass_; and in a short time longer it was so much changed as entirely to lose its identity. From these and numerous other facts, Dr Beaumont infers, that “there is a perfect admixture of the whole ingestæ during the period of alimentation and chymification;” and that “the whole contents of the stomach until chymification be nearly complete, exhibit a heterogeneous mass of solids and fluids--hard and soft, coarse and fine, crude and chymified--all intimately mixed, and circulating promiscuously through the gastric cavity, like the mixed contents of a close vessel, gently agitated or turned in the hand.” (P. 112.) As we proceed we shall meet with various indirect proofs of these statements being correct. If Dr Beaumont’s observations on this subject are accurate, we may expect to find that chymification commences _on the surface of each individual fragment_ of the food, and is not confined to the outer surface of the entire alimentary mass, as stated by Dr Philip. Such, accordingly, is the fact. When Dr Beaumont extracted a portion of the food through the opening half an hour or an hour after eating, he invariably found it composed of perfectly formed chyme and particles of food intimately mixed and blended; and in these experiments every portion of the aliment was already so completely supplied with gastric juice, that its chymification proceeded till the whole was digested with no other aid than that of the requisite heat and agitation. When a meal is taken before the preceding one is out of the stomach, digestion is observed to be disturbed. Dr Wilson Philip explains this by stating, that the newly swallowed food becomes imbedded in, and occupies the centre of, the older and half-digested mass, where it remains distinct and untouched till the former meal is entirely disposed of. A more logical explanation, however, and one more in harmony with facts, is offered by Dr Beaumont, who ascribes the disturbed digestion to _the supply of gastric juice having been entirely taken up by the first meal_, and to the stomach, now comparatively exhausted, being unable to secrete a fresh supply for the second--seeing that, in ordinary circumstances, its vessels secrete only enough to meet the real wants of the system. Dr Beaumont adduces in confirmation of this view, the fact that many children, and most cooks, are in the habit of eating _small_ quantities of food almost every hour or two without their digestion suffering materially, because then the amount of gastric juice secreted is quite equal to the chymification of the _whole_ quantity taken.