The experiment commenced on October 4, 1903, and for a period of six months every detail bearing upon the nutrition and condition of the men under the gradually changed conditions was carefully observed. Every precaution to preserve the health and good spirits of the men was taken. Pure distilled water was sent to the quarters each morning, magazines and other periodicals were supplied through the courtesy of friends, occasional visits to the theatre were indulged in; in fact all that could be done to counterbalance any possible depressing influence from the partial restraints of the experiment was arranged for. [Illustration: _Showing a group of the soldiers at work in the gymnasium._] Regarding the details of the work; the twenty-four hours’ urine was collected by each man, also the fæces for each day, and these were subjected to chemical analysis with a view to following out the various changes in the amount and character of the proteid metabolism going on in the body as measured by the output of total nitrogen, uric acid, and phosphoric acid in the urine, and by the amount of nitrogen in the fæces with reference to the degree of digestion and utilization of the proteid foods ingested. During the first two weeks the ordinary army rations were given to the men; later a gradual change was made, accompanied by a reduction in the amount of proteid food, with some reduction likewise in the total fuel value of the food. All the food placed before each man was carefully weighed, and at the close of every meal any uneaten food was weighed and the amount subtracted from the initial weights. During the balance periods, when the income and output of nitrogen were carefully compared, the food materials were weighed with greater care and large samples of each article were taken for analysis, to determine the exact content of nitrogen. Every figure for nitrogen shown in the tables was verified by at least a duplicate chemical analysis so as to avoid any possibility of error.