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. DAILY AVERAGES
| Date. | Body- weight. | Food. | Output. | Nitro- gen Balance + or – | ||||
|---|---|---|---|---|---|---|---|---|
Total | Nitro- | Fuel | Nitro- | Nitro- | Nitro- | |||
1905 | kilos | grams | gram | calories | grams | gram | gram | gram |
| July 18-July 28 | 6.8 | 5.88 | 0.84 | 79.0 | 5.58 | 0.43 | 0.05 | –0.18 |
| Aug. 15-Aug. 24 | 7.1 | 3.44 | 0.49 | 77.4 | 3.35 | 0.17 | 0.13 | –0.21 |
| Sept. 6-Sept. 15 | 6.9 | 2.11 | 0.30 | 80.0 | 1.93 | 0.21 | 0.07 | –0.10 |
| Oct. 8-Oct. 17 | 6.9 | 2.10 | 0.30 | 80.0 | 1.83 | 0.20 | 0.07 | 0 |
| Nov. 22-Dec. 1 | 6.0 | 1.83 | 0.31 | 80.0 | 1.48 | 0.21 | 0.11 | +0.03 |
1906 | ||||||||
| Jan. 2-Jan. 11 | 5.6 | 1.63 | 0.29 | 81.0 | 1.54 | 0.17 | 0.08 | –0.16 |
| Jan. 30-Feb. 8 | 5.5 | 1.63 | 0.30 | 82.0 | 1.60 | 0.15 | 0.05 | –0.17 |
| Feb. 27-Mar. 8 | 5.5 | 1.78 | 0.32 | 84.0 | 1.66 | 0.17 | 0.05 | –0.10 |
| Mar. 27-Apr. 5 | 5.7 | 1.98 | 0.34 | 81.0 | 1.75 | 0.21 | 0.06 | –0.04 |
| Apr. 24-May 3 | 5.7 | 1.98 | 0.34 | 83.0 | 1.68 | 0.13 | 0.13 | +0.04 |
| May 22-May 31 | 5.8 | 1.98 | 0.34 | 80.0 | 1.77 | 0.13 | 0.11 | –0.03 |
| June 17-June 26 | 6.0 | 1.98 | 0.33 | 77.0 | 1.53 | 0.21 | 0.07 | +0.17 |
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.
Subject No. 3. August 19, 1905
Subject No. 3. November 18, 1905
