Turning now to a second subject, designated as dog No. 3, the experiment with which lasted for nearly an entire year, the following general statements may be made. The animal was a small black and white fox terrier, weighing on July 6, 1905, 6.5 kilograms. It was a nervous, affectionate little creature, far less phlegmatic than the animal just described, always on the alert for a petting, and unceasingly active. For these reasons, it seemingly required per kilogram of body-weight a little more food than the preceding animal; a fact also in harmony with the general law that small animals, per unit of body-weight, need more food than larger ones. The diet made use of was of the same general character as employed with the preceding animal, and was changed from time to time to give requisite variety and to insure freedom from too great monotony. The accompanying table, showing daily averages during the twelve balance periods, gives all necessary information regarding the outcome of the experiment.

Subject No. 3. August 19, 1905.

Subject No 3 November 18. 1905.

Subjtct No. 3. April.24. 1906.

Subject No. 3 June 27 1906.

Subject No. 8. Daily Averages

It will be observed that daring 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 0.31-0.38 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.

Subject No. 18. Daily Averages

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.

Subject No. 13 January... 1906.

Subject No. 13. February 27, 1906.

Subject No. 13. April 24, 1906.

Subject No. 13. June 19, 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. 15. Daily Averages

Results of the same general tenor with dogs No. 15 and No. 20 are seen in the appended tables, while the accompanying photographs testify clearly to the general good condition of the animals up to the end of the experiments. In No. 20 particularly, the great gain in body-weight is to be noted, even though the fuel value of the food was reduced as low as 64 calories per kilo, with the nitrogen intake at 0.28 gram per kilo daily. Plainly, the day's food could have been diminished still more, with perfect safety to both body and nitrogen equilibrium.

Subject No. 90. Daily Averages