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. KEY: 1, percentage of nutrients; 2, fuel value of 1 pound in calories. The unit of heat, called a _calorie_, or gramme-degree, is the amount of heat which is necessary to raise one gramme (15.43 grains) of water one degree centigrade (1.8° Fahr.). A, round beef; B, sirloin beef; C, rib beef; D, leg of mutton; E, spare rib of pork; F, salt pork; G, smoked ham; H, fresh codfish; I, oysters; J, milk; K, butter; L, cheese; M, eggs; N, wheat bread; O, corn meal; P, oatmeal; Q, dried beans; R, rice; S, potatoes; T, sugar. This table, among other things, shows that the flesh of fish contains more water than that of warm-blooded animals. It may also be seen that animal foods contain the most water; and vegetable foods, except potatoes, the most nutrients. Proteids and fats exist only in small proportions in most vegetables, except beans and oatmeal. Vegetable foods are rich in carbohydrates while meats contain none. The fatter the meat the less the amount of water. Thus very lean meat may be almost four-fifths water, and fat pork almost one-tenth water.