Although the stomach carries on a certain part of the work of digestion, its primary purpose, as we shall see presently, is to serve as a storage place into which a considerable amount of food can be placed in a few moments and so enable us to do our eating at three or four definite meals instead of little by little throughout the day. When we rise from table after any meal, we have in our stomachs roughly one-third of our total food supply for the day, the exact proportion depending, of course, on our individual habits as regards our distribution of food-taking among the three meals. During the two to four hours following the meal this accumulated material in the stomach will be passed along little by little to the small intestine, which is the real digestive organ of the body. In the course of this time there will be some additional digestion within the stomach, but not enough to prepare any foodstuffs for actual use by the tissues. The outlet from the stomach to the small intestine is guarded by [Illustration: THE ALIMENTARY CANAL _A_, stomach; _J_, _I_, small intestine; near _CC_, vermiform appendix; _AC_, _TC_, _DC_, large intestine; _R_, rectum. (Martin’s “Human Body”)] another sphincter similar to that which closes the opening between the esophagus and stomach. This sphincter is ordinarily closed tightly, relaxing occasionally to let a little food through into the small intestine. It is interesting to note, however, that the sphincter does not hold against some materials; for example, water that is drunk between meals passes rapidly from the stomach on into the small intestine. It is said that raw oysters, raw white of egg, and other materials of a similar consistency also pass the sphincter immediately. Most other kinds of food material cannot pass unless the sphincter actually relaxes.