In addition to the amounts here mentioned, water is required. The following estimate is made by K. Vierordt for an adult in 24 hours; 120 gm. albumen, 90 gm. fat, 330 gm. carbohydrates, 2818 gm. of water. A fair average to be drawn from these estimates is, albumen 41⁄2 ounces (128 gm.), fat 3 ounces (90 gm.), carbohydrates 1 lb. (480 gm.) water 51⁄2 pints (2720 c.c.), as a minimum diet for an adult male doing moderate manual labor.

To determine this quantity of different foods it is necessary to know the composition of ordinary food-stuffs. In the following table is presented some of these facts:

Beef-tea boiled only half an hour, Dr. Haig states, does not contain so much uric acid as that given in the table. Hence it is probable that prolonged cooking and the digestive and metabolic processes would yield larger percentages of uric acid in the meat foods than the figures here given represent. Tea, coffee and cocoa do not contain uric acid, but do contain xanthin compounds which are equivalent to uric acid. It is usually considered that a healthy person requires the formation of 3 to 31⁄2 grains of urea per pound of body weight daily. As albumen furnishes one-third its weight of urea, it is easy to calculate the amount of albumen required in the food. Haig estimates that a man weighing 140 lbs. requires 10 oz. of bread, 2 oz. of oatmeal, 2 pints of milk, 11⁄2 oz. of pulses, 11⁄2 oz. of cheese, which in connection with other cereals, fruits, vegetables, etc., will furnish his quota of urea.

VII. The relative value of foods is shown in the following table from Scammell. (The figures represent percentages.)

The following table giving the potential energy of foods is useful in

this connection.

VIII.-TABLE OF ENERGY ESTIMATED IN FOOT TONS INSTEAD OF
CALORIES (YEO).

Energy developed by one ounce of the following foods when oxidised
in the body.

It is not enough to know the amount of food required to sustain the
body; we must also know something about the digestibility of foods. If
disease of the stomach exists whereby digestion is retarded, even though it
is finally accomplished, easily digestible food should be advised. In func-
tional dyspepsia, atony of the stomach, chronic gastritis and dilatation of
the stomach food ought to be prescribed which will not require several
hours to digest. The following table by Beaumont, showing the digestibil-
ity of various alimentary substances in the stomach is most valuable :
IX-TIME REQUIRED TO DIGEST CERTAIN FOODS.