The composition of oats varies somewhat from that of wheat, rye and barley. They contain a larger proportion of both fat and proteids, and form a desirable food if correctly prepared. The objection to oats as an article of diet is the hasty manner in which they are usually prepared, which converts them into a gummy mass of gelatinized starch, entangled with the peculiar gummy proteid of the oat grain. Thus prepared the oat is a most prolific source of disturbed digestion. [Sidenote: Corn] Corn is the cheapest material capable of nourishing the human body that is produced in the temperate zone. It is less digestible, and more deficient in the salts than the group of grains thus far mentioned. It is very wholesome, however, but in no way superior to other grains. In the future corn will probably play an increasing part in the problem of feeding the world, as a cheap source of carbohydrates, and for the purpose of manufacturing glucose. [Sidenote: Rice] In all tropical and semi-tropical countries rice occupies the same position that corn does in the temperate zone. It is more deficient in proteids and in fat than any other food grain, while the starch of rice is more easily digested than any other form of cereal starch. This grain, however, is almost entirely devoid of mineral constituents, and for this reason it is productive of serious nutritive derangements when indulged in too freely. This deficiency can be overcome by taking a liberal quantity of green salads, or fresh vegetables, whenever rice is eaten. [Sidenote: Buckwheat] Buckwheat is a grain whose consumption is very limited, owing to the fact that it is dark in color. It compares favorably with wheat and corn as to nutritive elements, and is now much used as a winter food by the northern people. USES OF GRAINS The use of grains as an article of food may be considered under three headings: 1 As a source of energy 2 As a source of nitrogen 3 Grain as a remedial food; that is, as a source of cellulose or roughness, for the regulation of intestinal action (1) GRAIN AS A SOURCE OF ENERGY [Sidenote: Too much grain consumed] All grains are composed largely of starch, therefore the question of energy to be derived from this source is one of assimilation and use. The use of grains in the diet deserves the most careful consideration, and the study should not be confined to any particular grain, but to the entire group, and especially to the method of preparation, and the quantity that should be consumed under the varying conditions of age, temperature of environment, and work or activity. The conventional American diet contains such an abnormal quantity of grain-starch, and the methods of preparation are so unnatural, that the Food Scientist, in practise, will find many people whose digestive organs have become so deranged that he may deem it necessary to prohibit grain-starch almost entirely.