+----------------+-------+------+-------+--------+-------+-------+-------+------+ It will be observed that during the first three months the animal showed a tendency to gain in weight slightly, recalling that its initial weight on July 6 was 6.5 kilograms. Later, the weight fell off a little, but in March it showed an upward movement, though very gradual. With the amount of proteid food given, it is evident that the animal needed about 80 calories per kilo to maintain a condition of body-equilibrium. Nitrogen equilibrium was practically maintained throughout the larger portion of the twelve months, but evidently the animal required 0.31–0.33 gram of nitrogen per kilogram of body-weight. Attention may be directed, in view of the results reported by Munk regarding loss of the power of absorption and utilization of proteid food, to the figures showing the average daily output of nitrogen through the excrement. It is plain from the data presented, that this animal was not suffering from any trouble of this order; indeed, the utilization of proteid food throughout the entire experiment was exceedingly complete, as shown by the relatively small loss of nitrogen through the excrement, thus implying vigorous and unimpaired digestion, together with thorough absorption of the products formed. The accompanying photographs show the appearance of the animal on August 19, 1905, November 18, 1905, April 3 and June 27, 1906, the close of the experiment. [Illustration: _Subject No. 3._ _August 19, 1905_] [Illustration: _Subject No. 3._ _November 18, 1905_] [Illustration: _Subject No. 3._ _April 24, 1906_] [Illustration: _Subject No. 3._ _June 27, 1906_] Passing now to the third subject, we have an experiment of somewhat shorter duration, viz., of nine months, but sufficiently long to afford ample opportunity for any deleterious effect to manifest itself. The initial weight of the dog, No. 13, was 14.5 kilograms on September 14. The lowest intake of nitrogen was 0.26 gram per kilo of body-weight per day, while the fuel value of the daily food was during one period reduced to 55 calories per kilo. A daily proteid consumption equalling 0.30 gram of nitrogen per kilo, with a total fuel value in the day’s food of 66–70 calories per kilo, was clearly quite sufficient to maintain nitrogen equilibrium and body-weight; indeed, toward the end of the experiment, the animal commenced to gain in weight quite noticeably on the above diet, and was laying by fairly large amounts of nitrogen daily. The accompanying table gives the average daily nitrogen exchange, etc., of the nine balance periods, while the photographs, taken on the dates indicated under each, show the appearance of the animal at various times. SUBJECT No. 13. DAILY AVERAGES