Armed with letters of recommendation to the President and to the Secretary of War from General Wood, and an invitation from Surgeon-General O’Reilly to call on him if coöperation on his part were desired, the writer returned to the United States and consulted with Professors Chittenden and Bowditch relative to the desirability of army coöperation. It was believed to be just the thing wanted to facilitate the inquiry, and the writer proceeded to Washington to effect the combination. General O’Reilly had already had the matter under consideration and was quite ready to draw up a project for presentation to the Secretary of War when Mr. Root should return to Washington from his summer vacation. Twenty privates and three non-commissioned officers of the Hospital Corps of the United States Army under command of Dr. Lieutenant Wallace DeWitt are now quartered at New Haven in coöperation with the staff of the Sheffield Scientific School. It is the intention to learn, if possible, how little nitrogen is necessary to secure the best human efficiency; and also, if possible, to ascertain some measure of the evil effects of an excess of nitrogenous food as well as excess of food in general upon human efficiency. The writer is grateful for the good fortune of being able to be of service in a development of interest in a subject which is of vital importance to the human race. He has enjoyed the benefits of an economic nutrition and knows its value. The practical proof of a subject of personal application must come from such personal application. Each person must be his own doctor and his own scientist in the matter of his alimentation or he runs the risk of running amuck in his health economy. There is not so much to learn, neither is there very much to do to insure right alimentation, perfect digestion, and continuous good health; but the little required of us must be attended to with no lapses of attention.—HORACE FLETCHER.] PHYSIOLOGICAL ECONOMY IN NUTRITION BY RUSSELL H. CHITTENDEN _Director of the Sheffield Scientific School of Yale University_