Peas and beans differ from the other vegetable food-products thus far considered, in that they are rich in nitrogenous matter. They are frequently spoken of as good substitutes for meat. Their chief nitrogenous constituent is legumin, a protein, which in many of its chemical reactions resembles casein. They also contain much carbohydrate and little fat. Beans and peas are not quickly digested, and, as ordinarily cooked and eaten, are not very perfectly absorbed from the intestine. If they are simply boiled, a large plateful will not be disposed of by the stomach for from four to five hours. Forty per cent, of their protein will be lost in the intestine. However, if they are eaten after they have been ground to a fine flour, only 8 or 9 per cent, will be lost. They are most digestible when made into mush or prepared as a puree. They are highly nutritious, but should be supplemented by fats. String-beans and wax beans are eaten when young, and the pod as well as the bean is eaten. The former consists largely of cellulose. It contains little nourishment and is not easy to digest. Beans, especially dried beans, are likely to cause flatulence. This is in large part due to their slow digestion. They also contain sulphur and form sul-phureted hydrogen in the alimentary canal.

The following table of analyses, taken from a bulletin of the United States Department of Agriculture, gives the composition of this important group of foods:

Composition Of Fresh And Dried Legumes Compared With That Of Other Foods