111.  Vegetable Foods.  This is a large and important group of foods, and embraces a remarkable number of different kinds of diet.  Vegetable foods include the cereals, garden vegetables, the fruits, and other less important articles.  These foods supply a certain quantity of albumen and fat, but their chief use is to furnish starches, sugars, acids, and salts.  The vegetable foods indirectly supply the body with a large amount of water, which they absorb in cooking.

112.  Proteid Vegetable Foods.  The most important proteid vegetable foods are those derived from the grains of cereals and certain leguminous seeds, as peas and beans.  The grains when ground make the various flours or meals.  They contain a large quantity of starch, a proteid substance peculiar to them called gluten, and mineral salts, especially phosphate of lime.  Peas and beans contain a smaller proportion of starch, but more proteid matter, called legumin, or vegetable casein.  Of the cereal foods, wheat is that most generally useful.  Wheat, and corn and oatmeal form most important articles of diet.  Wheat flour has starch, sugar, and gluten—­nearly everything to support life except fat.

Oatmeal is rich in proteids.  In some countries, as Scotland, it forms an important article of diet, in the form of porridge or oatmeal cakes.

Corn meal is not only rich in nitrogen, but the proportion of fat is also large; hence it is a most important and nutritious article of food.  Rice, on the other hand, contains less proteids than any other cereal grain, and is the least nutritious.  Where used as a staple article of food, as in India, it is commonly mixed with milk, cheese, or other nutritious substances.  Peas and beans, distinguished from all other vegetables by their large amount of proteids—­excel in this respect even beef, mutton, and fish.  They take the place of meats with those who believe in a vegetable diet.

113.  Non-proteid Vegetable Foods.  The common potato is the best type of non-proteid vegetable food.  When properly cooked it is easily digested and makes an excellent food.  It contains about 75 per cent of water, about 20 per cent of carbohydrates, chiefly starch, 2 per cent of proteids, and a little fat and saline matters.  But being deficient in flesh-forming materials, it is unfit for an exclusive food, but is best used with milk, meat, and other foods richer in proteid substances.  Sweet potatoes, of late years extensively used as food, are rich in starch and sugar.  Arrowroot, sago, tapioca, and similar foods are nutritious, and easily digested, and with milk furnish excellent articles of diet, especially for invalids and children.

Explanation of the Graphic Chart.  The graphic chart, on the next page, presents in a succinct and easily understood form the composition of food materials as they are bought in the market, including the edible and non-edible portions.  It has been condensed from Dr. W. O. Atwater’s valuable monograph on “Foods and Diet.”  This work is known as the Yearbook of the U.S.  Department of Agriculture for 1894.