Subsidiary evidence regarding the normal nitrogen excretion is supplied by the average excretion of nitrogen found with the class in physiology in the Harvard Medical School for a number of years past. In the absence of Professor Walter B. Cannon, we must rely upon lecture notes kindly placed at our disposal by Dr. T. M. Carpenter. From analyses of the urinary output of these groups of 40 or more medical students, collected for three successive days, in the years 1909 to 1915, inclusive, the following average values per man per day were obtained: 13.8, 12.0, 12.7, 13.3, 12.7, 12.2, and 12.2 grams of nitrogen excreted. These values are distinctly lower than one would expect when it is considered that the American is commonly believed to live upon the so-called Voit protein standard. The low values found by us with the Y. M. C. A. College students might perhaps be ascribed to the strong tendency at the present time to conserve on meat products, and incidentally on protein foods, the physiological thought in this case being undoubtedly profoundly influenced by the experiments of Professor Chittenden. On the other hand, the fact that the students at the Harvard Medical School have shown these low values since 1909 indicates that the earlier estimates of the American excretion of nitrogen must have been high. The values we find, therefore, are not surprisingly low, and this subsidiary evidence obtained with the medical students confirms our belief that the normal nitrogen excretion of the Y. M. C. A. College undergraduate is not far from 13 to 14 grams. The excessive physical exercise and probably larger amounts of food eaten by the students of the Springfield college, as compared with the students of the Harvard Medical School, would normally account for the slightly higher nitrogen output and protein level at which they were living.