The United States Department of Agriculture has for several years been conducting a series of experiments to determine the dietary value of different foods.

Nine dietary studies and thirty-one digestion experiments were carried on. In the majority of the dietary studies, and all but one of the digestion experiments, fruit and nuts constituted all, or almost all, of the diet. The results of the investigation emphasise the fact that both fruit and nuts should be considered as true foods rather than food accessories. The subjects were two women, three children, two elderly men, and two university students. The men all did hard manual labor during a part of the time, the students working to support themselves while pursuing their studies.

The fare given in these experiments was in every case one that would appeal to any normal appetite. It embraced honey, tomatoes, apples, bananas, cantaloupe, grapes verdal, cornichon, tokay, muscat, scarlet haws, pears, pomegranates, persimmons, oranges, strawberries, watermelons, figs, almonds, and peanut butter. The only animal foods allowed were cottage cheese and eggs ; and these in limited quantities. The cost of such a diet varied from 15 to 18 cents a day. Comparative experiments were carried along in which animal foods were employed under the usual conditions of living, and in these the daily cost ran from 26 to 30 cents. It was found that the food eaten supplied about 60 per cent, of the protein usually secured by the average meat diet, while health and strength continued the same, if not improved, and in two or three cases there was a slight gain in flesh and weight.

One of the chief objects of the series of experiments was to furnish data as to the value of nuts as food. Fruits contain little protein, and nuts are relied on in the fruitarian plan of eating to balance the ration. Fruits are rich in carbohydrates, and nuts in fat. A pound of peanuts, which costs 7 cents, furnishes 1,000 calories of energy at a cost of 3 1/2 cents, and protein at a cost of 36 cents per pound. A porterhouse steak costs for the same result respectively 22 1/2 cents and $1.31, when the steak can be bought for 25 cents per pound.

The average price per pound of the protein of nuts ranges higher than the corresponding average of meats; but the cost per pound of peanut protein is lower than for meats, fish, eggs, milk, diary produce, and prepared cereals. The only foods which furnish protein at a less cost than peanuts are flour and dried beans. According to Prof. Jaffa's experiments, nuts are the cheapest source of energy for the fruitarian, the peanut ranging far ahead of any other variety.