The oesophagus terminates in the stomach, which has two orifices, the cardiac, or upper, and the pyloric, or lower. The stomach has three coats, - the serous, the muscular, and the mucous. While the food is in the stomach the gastric juice acts on it. The stomach now churns it up and gradually liquefies it, and thus fits it for passing on to the small intestines and for absorption into the blood.

Composition Of Gastric Juice

The water holds the other ingredients in solution. The hydrochloric acid acidulates the food and prevents fermentation. Its absence or lessening or excess causes troubles of one kind or another. Pepsin is part of the organic matter of the juice. It is called a hydrolytic ferment or enzyme. The pepsin transforms the acidulated proteids, such as exist in meats, eggs, and similar foods, into new forms that can be absorbed into the blood.

Rennin is another organic matter in the juice. It has the power of coagulating the casein of milk. Stomach digestion is a complex process, involving many glands, cells, etc. The chief action of the gastric juice is to transform the proteids into peptones. They are the final product of the digestion of proteids, - that is, meats and such. It takes the stomach from three to five hours to digest an average meal. Much depends on the composition of the food taken. As the food is digested in the stomach it passes into the intestines through the pylorus.

Whipped eggs, raw, should digest in one hour and twenty minutes; soft-boiled in three hours; hard-boiled in three hours and a half; barley soup in one hour and a half; bean soup in three hours; chicken soup in three hours; mutton soup in three hours and a half; raw oysters in three hours; stewed oysters take a half hour longer; broiled lamb chops in two hours and a half; veal chops in four hours; roast pork, over five hours; broiled beefsteak in three hours; roast turkey in two hours and twenty-five minutes; chicken, boiled, in four hours, and stewed in two hours and three-quarters; roast duck in four hours; beef liver in two hours; fried sausage in three hours and a quarter.

There is much difference in the time of digesting the various vegetables. It takes boiled cabbage four hours and a half; boiled turnips three hours and a half; boiled parsnips two hours and a half; boiled beets three hours and three-quarters; boiled beans two hours and a half; boiled green corn three hours and three-quarters; roasted potatoes (white) two hours and a half; boiled white potatoes three hours and a half. This shows baking to be the proper method of cooking white potatoes.