What now do the nitrogen figures show regarding the amount of proteid material metabolized each day? It will be remembered that the Voit standard calls for 118 grams of proteid or albuminous food daily, of which 105 grams should be absorbable, in order to maintain the body in a condition of nitrogen equilibrium, and in a state of physical vigor and general tone. This would mean a daily excretion through the urine of at least 16 grams of nitrogen. The daily output of nitrogen in the case under discussion, however, was 5.699 grams for a period of nearly nine months. This amount of nitrogen excreted through the urine means only 35.6 grams of proteid metabolized, or about one-third the amount called for by the Voit standard, or the standards generally adopted as expressing man’s daily requirement of proteid food. But was the body in nitrogenous equilibrium on this small amount of proteid food? Naturally, this question might be answered in the affirmative, on the basis of the constancy in body-weight for the period from October to June, but more decisive proof is needed. The question was therefore settled by a careful comparison of the income and output, in which all the food eaten was carefully weighed and analyzed, while the nitrogen of the urine and fæces was determined with equal accuracy. The first experiment of this character to be quoted is for the week commencing March 20, a period of six days. Following are the diets made use of each day, the weights of the various food-stuffs being given in grams. Likewise is shown the nitrogen content of the several food-stuffs for each day, and also a comparison of the nitrogen intake with the output of nitrogen through the urine: _Sunday, March 20, 1904._ Breakfast, 7.45 A. M.—One cup coffee, _i. e._, coffee 137.5 grams, cream 30.5 grams, sugar 9 grams. Dinner, 1.30 P. M.—Stewed chicken 50 grams, mashed potato 131 grams, biscuit 49 grams, butter 13 grams, chocolate pudding 106 grams, one small cup coffee, _i. e._, coffee 64 grams, sugar 12 grams, cheese crackers 29 grams. Supper, 6.30 P. M.—Lettuce sandwiches 56 grams, biscuit 35 grams, butter 6 grams, one cup tea, _i. e._, tea 170 grams, sugar 7 grams, sponge cake 47 grams, sliced oranges 82 grams. Food. Grams. Per cent Nitrogen. Total Nitrogen.