In analyzing the effect of the factors of the bread-potato-fruit diet Hindhede found that an exclusive bread diet gave a urine which exhibited a strong tendency to deposit uric acid, and notes that the Russian peasant, who works fourteen to sixteen hours daily and lives almost exclusively upon bread, frequently has gravel. On the other hand, potatoes when ingested yield a urine which is very slightly acid, often on the border-line of alkalinity, and one which has a very great solvent power over uric acid.

It is a curious fact that the potato, long proscribed by many physicians, has decided therapeutic value. Some one has remarked, "One meets the potato today in the very best circles".

1 Hindhede: "Skan. Archiv fur Physiologic," 1912, xxvii, 87.

Hindhede1 reports the following results upon the daily nitrogen balance after giving various forms of bread during periods of eight days:

These results show a favorable utilization of bread protein.

Concerning the utilization of potato protein Hindhede2 reports the following remarkable experiment: An individual partook of a diet of 2 to 4 kilograms of potatoes with some margarin daily during a period of nearly three hundred days. The potatoes were well boiled in water and the water in which they were cooked was drunk on account of valued salts therein contained. The rule was to eat only when hungry. Potatoes could be eaten at the rate of 100 grams in four minutes. Stools were passed once every three or four days, but there was no constipation. During a period of one hundred and seventy-eight days 6.05 grams of nitrogen and 3725 calories were contained in the daily diet, and there occurred an average daily loss of body nitrogen of 0.42 gram. During a second period of ninety-five days, when mechanical work was performed, there were 8.45 grams of nitrogen and 4900 calories in the daily diet and the daily loss of body nitrogen was 0.36 gram. During these ninety-five days the food supply consisted of 350 kilograms of potatoes and 22 kilograms of fat taken in the form of margarin.

Hindhede states that he "feels weak" after taking much meat.

One may pass now to the other side of the story.

Lichtenfelt3 shows that while there is no statistical difference in the height of individuals as due to occupation, still the people of southern Italy are not so large nor so well developed physically as their fellows of northern Italy. He explains this stunted growth as due to a low protein and calorific intake in the food.

1 Hindhede: "Skan. Archiv fur Physiologie," 1913, xxviii, 165.

2 Hindhede: Ibid., 1913, xxx, 97.

3 Lichtenfelt: "Pfluger's Archiv," 1905, cvii, 57.

Albertoni and Rossi1 describe how the poorest Italian peasants in southern Italy live on cornmeal, green stuffs, and olive oil, and have done so for generations. There is no milk, cheese, or eggs in their dietary. Meat in the form of fat pork is taken three or four times a year. Cornmeal is taken as "polenta," or is mixed with beans and oil, or is made into corn-bread. Cabbage or the leaves of beets are boiled in water and then eaten with oil flavored with garlic or Spanish pepper. The average elimination of urinary nitrogen of 13 persons in three families when taking this diet was for men 8.1 and for women 6.7 grams of nitrogen daily. The investigators, furthermore, considered a family of 8 individuals of whom 2 were children. The annual income was 424 francs or $84. Of this, 3 cents per day per adult was spent for food and the remaining 3/5 cent daily was spent for other purposes. The addition of 100 to 200 grams of meat daily to the diet of each of these individuals increased their muscular power, and the investigators believed that such an addition was essential to mental health as well.

The position of the food extremists was powerfully attacked by Rubner,2 whose general tone was in advocacy of variety in the dietary of man in accordance with the then prevailing habits and certainly without attempting to conform to a protein minimum. Since the outbreak of the war, with the food restrictions which have accompanied it, Rubner has become convinced that a restricted protein dietary is without harmful influence. This information has been given the author through a reliable source. For Rubner's ideas of practical food reform see p. 570.

Hirschfeld3 finds that the actual ration of a German soldier contains 98 grams of protein, with no untoward results. He states that writers on economics, who believe the German populace underfed because they do not have 118 grams of protein daily, are unduly pessimistic.

1 Albertoni and Rossi: "Archiv fur experimentelle Pathologie und Phanna-kologie," 1908, Supplement, p. 20.

2 Rubner: "Ueber moderne Ernahrungsreformen," Berlin, 1914.

3 Hirschfeld: "Archiv fur Physiologie," 1903, p. 380.

Although, as has been stated, the battleground has been over the allowance of 118 grams in Voit's dietary, it will be surprising to many to learn that Voit himself said little on the subject. He1 showed that a vegetarian can live in nitrogenous equilibrium on a diet containing 48.5 grams of protein and that an active working man weighing 74 kilos may get along on less than 118 grams. He discouraged the tendency to eat meat in excess. He also discouraged the practice of vegetarians who overload the digestive tract with the coarser kinds of vegetable foods which leave large indigestible residues.

It is not to be denied that 50 grams of protein (containing 8 grams of nitrogen) are apparently able to maintain the adult body machine in perfect repair. Vegetarians, fruitarians2 (who live on fruit and nuts), and vigorous adults, who largely exclude protein from the diet, are evidently able to live in health and strength upon this quantity. It must be, however, that more than this amount is advisable during growth or convalescence from wasting disease, or during the muscular hypertrophy which accompanies preliminary training for athletic effort.

Abderhalden3 mentions the fact that since various body tissues are constructed of different proteins, therefore a large variety of amino-acids in sufficient quantity must be available for their proper replenishment. Hence, it is reasonable to assume that an excess of food protein is essential to supply the special amino-products for the synthesis of the characteristic proteins of the blood-serum and those of the different organs.

It is certain that large ingestion of protein in hot weather increases the heat production with accompanying increase in perspiration (p. 235). Meat should therefore be avoided in hot weather. In cold weather such an extra heat production may produce a pleasurable sensation of warmth. Dr. Folin, in personal conversation with the writer, said that a dietary of carbohydrates, fat, and low protein was easily borne by an individual during the summer, but during the winter the man complained of his sensitiveness to cold when taking the same diet.

1 Voit: "Zeitschrift fur Biologie," 1889, xxv, 278.

2 Jaffa: U. S. Department of Agriculture, 1903, Bulletin No. 132.

3 Abderhalden: "Zentralblatt fur d. ges. Physiol, und Path. d. Stoffwech-sels," 1906, i, 225.