TOPICS: Dietary experiments with a detail of soldiers from the United States army. General character of the army ration. Samples of the daily dietary adopted. Rate of nitrogen metabolism attained. Effect on body-weight. Nitrogen balance with lowered proteid consumption. Influence of low proteid on muscular strength of soldiers and athletes. Effect on fatigue. Effect on physical endurance. Fisher’s experiments on endurance. Dangers of underfeeding. Dietary observations on fruitarians. Observations on Japanese. Recent dietary changes in Japanese army and navy. Observations of Dr. Hunt on resistance of low proteid animals to poisons. Conclusions. General acceptance of a new theory, or a new point of view, can be expected only when there is an adequate amount of scientific evidence on which the theory can safely rest. Facts cannot be ignored, and the larger the amount of supporting evidence the more certain becomes the general truth of the theory to which it points. Corroborative evidence, therefore, is always desirable, and he who would open up a new point of view must be zealous in accumulating facts to uphold his position. Critics there are without number who are ever ready to pick flaws in an argument or overturn a theory, especially if the one or the other stands opposed to their own point of view. This, however, is highly advantageous for the advance of sound knowledge, since it necessarily prompts the advocate to search in all directions for added data, by which he can build a bulwark of fact sufficient to defy just criticism. Further, the true scientific spirit demands persistent and painstaking effort in the search after truth, that error and misconception may be avoided. In harmony with these ideas, our attempt to ascertain the real needs of the body for proteid food led us to enlarge our evidence by a series of experiments with still another body of men, _i. e._, a detail of soldiers from the United States army.[61] This was a somewhat more difficult and ambitious undertaking, since the number of subjects involved was larger, and because with this group of men we could not expect quite that high degree of intelligent co-operation afforded by the preceding subjects. Still, this very fact was in a sense an added inducement, since it offered the opportunity of experimenting with a body of men who naturally would not take kindly to anything that looked like deprivation, and whose continued co-operation could be expected only by satisfying their natural demands for food. If this could be accomplished by an intelligent prescription in their daily diet, and the experiment brought to a successful conclusion, with maintenance of body-weight, nitrogen equilibrium, health, strength, and general vigor; with an intake of proteid food essentially equal to that adopted by the preceding subjects, corroborative evidence of the highest value would be obtained.