albumen of the chyme is capable of being converted only into a loose and tender solid. In passing from its state in the egg to its state in the chyme, the albumen has combined with a portion of water which has entered as an essential ingredient into its composition. By this combination the compound is reduced from what may be called a strong to a weak state. This is the first action exerted by the stomach on most alimentary substances. They are changed from a concentrated to a diluted, from a strong to a weak state: the power by which the stomach effects this change is called its reducing power, and the agent by which it accomplishes it is the gastric juice; the essential ingredient of which has been shown to be muriatic acid, or chlorine (639, _et seq._). The muriatic acid obtained from the common salt of the blood is poured in the form of gastric juice into the stomach, dissolves the food, combines it with water, reduces it from a concentrated solid to a dilute fluid; and thus brings it into the condition proper for the subsequent part of the process. 2. A converting power. Since whatever be the varieties of food, the chyme invariably forms a homogeneous fluid, the stomach must be endowed with the power of transforming the simple alimentary principles into one another; the saccharine into the oily, and the oily into the albuminous. The transformation of the saccharine into the oleaginous principle is traceable out of the body in the conversion of sugar into alcohol, which is essentially an oil. That the same transformation takes place within the body is indubitable. The oleagenous and the albuminous principles are already so nearly allied in nature to animal substance that they do not need to undergo any essential change in their composition. 3. A completing power. When the alimentary substances have been reduced and formed into chyme, when the chyme has been converted into chyle, and when the chyle absorbed by the lacteals is transmitted to the mesenteric glands, it undergoes during its passage through these organs a process the direct reverse of that to which it is subjected in the stomach; for whereas it is the office of the stomach to combine the alimentary substances with water, it is one office of the mesenteric glands to remove the superfluous water of the chyle; to abstract whatever particles of matter may be contained in the compound which are not indispensable to it, and to concentrate its essential constituents; and consequently these organs exert on the digested aliment a completing, in contradistinction to a reducing power.