Nitrogen balance for seven days = +2.663 grams. Nitrogen balance per day = +0.380 gram. Average Intake. Calories per day 2448. Nitrogen per day 8.192 grams. In this period of seven days the average daily intake of nitrogen was 8.192 grams, or only 0.36 gram per day more than in the first balance period, while the average fuel value of the food amounted to 2448 calories per day. Yet the average daily output of nitrogen through the urine for this period was 6.31 grams, or 1.2 grams per day less than in the first balance experiment. Further, under the conditions of this balance experiment, the body was laying up 0.380 gram of nitrogen per day, _i. e._, showing a plus balance of 2.66 grams of nitrogen for the seven days’ period. Again, it is to be noted that the average daily amount of nitrogen metabolized, 6.31 grams, was 0.22 gram less than the average daily nitrogen excretion for the entire seven months’ period, 6.53 grams. Evidently, this subject was quite able to maintain nitrogen equilibrium with a metabolism of only 6.31 grams of nitrogen per day, on a daily diet having a fuel value of about 2400 calories. Indeed, taking into account the amount of the plus nitrogen balance, it is evident that the daily food was somewhat in excess of the real requirements of the body, under the then existing conditions of body-weight and bodily activity. Again, we would call attention to the thorough utilization of the food in this experiment, emphasizing at the same time the voluminous character of the diet, together with its largely vegetable nature. The contrast between the diet made use of by Dr. Mendel and that used by the subject of the first experiment is quite striking, since the latter employed a much more concentrated diet with an average fuel value of only 1600 calories. Yet with a total intake of 57.343 grams of nitrogen for the seven days of Dr. Mendel’s balance period, 10.5 grams only passed out through the rectum, or 18.3 per cent, while in the second nitrogen balance of the first subject, with the more concentrated diet, 17.1 per cent of the total ingested nitrogen appeared in the fæces. In view of the great divergence in the character and volume of the intake, it is rather remarkable there should be so little difference in the relative utilization of the two diets.