With a view to testing some of these points and thereby broaden the scope of the investigation and enhance the value of the study, a group of eight students in the University, all trained athletes, was secured. These men volunteered to aid in the study, and at considerable self-sacrifice gave intelligent and hearty co-operation in all ways possible. The men were under observation from January 15, 1904, to the middle of June, 1904, a period of five months. From January 15 the urine was collected daily, and for a period of ten days the regular diet of the men was adhered to without any deviation whatever, with a view to ascertaining the extent of the proteid metabolism characteristic of each individual. No restrictions whatever in diet were suggested, but the ordinary food that the men were accustomed to eat while in training was taken. After this period the men were instructed to diminish somewhat the intake of proteid food, and in following out this plan most of the men diminished quite appreciably the quantity of food consumed at breakfast time, and in some cases stopped taking food of any kind at breakfast other than a cereal, with possibly coffee. No specific diet was imposed, but the men, being willing collaborators in the experiment, gradually cut down the intake of proteid food, diminishing likewise in considerable measure the total volume of food for the twenty-four hours. [Illustration: STAPLETON _Photograph taken in the middle of the experiment, in April._] The following brief description of the men, taken from Dr. Anderson’s report of their physical condition, to be referred to later, will suffice to make clear the characteristics (as athletes) of these subjects of study: Mr. G. W. Anderson is a foot-ball, base-ball, and basket-ball player, as well as a crew man (not Varsity). Well built and an all round athlete. 26.5 years of age. Mr. W. L. Anderson, a “Y” athlete (hurdler), the captain of the Yale Gymnastic Team, University Gymnastic Champion, and American Collegiate Gymnastic Champion. 21.5 years of age. Mr. H. S. Bellis, a member of the Y. G. A., a gymnast and acrobat and in constant training. 26 years of age. Dr. W. H. Callahan, Medical Assistant at the Gymnasium, in daily practice in the gymnasium; bowling, hand-ball, and running. 27 years of age. Mr. M. Donahue, a very muscular and versatile athlete, a foot-ball player and a Varsity basket-ball player. 25 years of age. Mr. C. S. Jacobus, a “Y” athlete, a noted long-distance man, and one of the best University runners. 22.3 years of age. Mr. H. R. Schenker, an active member of the Y. G. A., a point winner and intercollegiate competitor in gymnastics. 22 years of age. Mr. John Stapleton, a wrestler and gymnast. A professional, a man of large body and great strength. 24 years of age.