On August 25, a radical change was made in the diet, by reducing the amount of meat to 70 grams daily, thereby lowering the intake of nitrogen to 4.76 grams, or 0.27 gram per kilo of body-weight; the cracker dust and lard being kept at essentially the same levels as before. This diet was continued through the next balance period, the dog in the meantime gaining in body-weight, and showing for the second balance period an average gain by the body of half a gram of nitrogen per day. The food was then altered by substituting bread for the cracker dust, but so adjusted that the nitrogen and fuel values of the day’s food remained practically unchanged. There was still, however, a gain in body-weight and a slight gain in body nitrogen. At the close of the third balance period, the diet was again altered, one-half of the meat being replaced by milk, while cracker dust was substituted for the bread. The morning meal consisted of 170 grams of milk, 86 grams of cracker dust, and 18 grams of lard, while the afternoon meal was composed of 35 grams of meat, 63 grams of cracker, and 35 grams of lard. The day’s ration, however, still contained 4.76 grams of nitrogen and had a fuel value of 1249 calories. This diet was maintained until November 20, when the animal was again placed on a daily ration of meat (69 grams), bread (166 grams), and lard (80 grams), with a total fuel value of 1228 calories and 4.77 grams of nitrogen. This was continued until December 2, the dog still showing a plus nitrogen balance, but with a little loss in body-weight. On December 2, the diet was again changed by substituting milk for a portion of the meat, but the nitrogen and fuel values were maintained at the same level as before. After a week, December 9, the food was modified as follows: the morning meal contained 170 grams of milk, 110 grams of rice, and 11 grams of lard, while the afternoon meal was composed of 35 grams of meat, 81 grams of rice, and 30 grams of lard. The total nitrogen content of the day’s ration was 4.07 grams, while the fuel value was 1255 calories. At this time, the animal weighed 17.1 kilograms, consequently the intake of nitrogen had been reduced to 0.23 gram per kilo of body-weight, while the fuel value stood at 73 calories per kilogram. This diet was continued until February 9, the balance period, between January 2 and 11, showing that the animal was in nitrogen equilibrium, in spite of the material reduction in the intake of proteid, and that body-weight was increasing. The next balance period, January 30 to February 8, showed still further gain in weight with continuance of nitrogen equilibrium. On February 9, the diet was changed by returning to 70 grams of meat, 158 grams of cracker dust, and 60 grams of lard, with a daily intake of 0.28 gram of nitrogen per kilo of body-weight.