These results obtained with this body of United States soldiers, living on a prescribed diet and exposed to the stress and strain of military discipline with its attendant duties, together with the gymnastic work and training required each day, confirm in every detail the conclusions arrived at with the preceding group of professional workers. Once accustomed to a more sparing proteid diet, less rich in nitrogen, each one of these subjects had no difficulty in maintaining body-weight on the simpler and lighter food provided. No great difficulty was experienced in establishing a condition of nitrogenous equilibrium with this lowered intake of proteid food, neither was it necessary to increase the amounts of non-nitrogenous foods (fats and carbohydrates) to accomplish this end. The bodies of these men were quite able to adjust themselves to a lowered proteid metabolism, and physiologically speaking, one might well conjecture whether we have not in this condition a nearer approach to the normal and ideal state of the body than when the latter is struggling daily with 118 grams of proteid food, reinforced by fats and carbohydrates correspondingly increased in amount. However this may be, the members of the soldier detail were able to live for five consecutive months with a proteid metabolism corresponding to 7 to 8 grams of nitrogen per day, with maintenance of body-weight and without discomfort or loss of bodily vigor. It was easy in most instances to prove the establishment of nitrogen equilibrium with a daily intake of 8.5 to 9.5 grams of nitrogen, and with a total fuel value of the daily food equal to 2500 to 2800 calories. In other words, a metabolism of less than 50 grams of proteid per day was quite sufficient for the needs of the body, and a fuel value of 2500 to 2600 calories was ample to meet the requirements of the men under the then existing conditions of bodily and mental activity. Are we not justified, therefore, in again asking the question, why should we hold and teach the doctrine that the healthy adult needs to metabolize 105 grams of proteid food daily? As Voit has well said, the smallest amount of food that will serve to maintain physiological equilibrium and keep up health and strength is the ideal diet. The eleven subjects of this Hospital detachment, who remained throughout the experiment, were apparently able to maintain physiological equilibrium and preserve their health and strength under the conditions of diet as described, thereby demonstrating the possibilities of a physiological economy corresponding to a saving of full fifty per cent or more in proteid food; a saving of possibly great physiological import, to say nothing of the possible economic and sociological importance of the saving. Further, we may add that the minimal proteid requirement as evidenced by the results of these experiments is more than fifty per cent lower than the figures quoted by