Dr. Underhill, at the beginning of the experiment, July 1, 1903, was twenty-six years of age and weighed 67.6 kilos. For a period of two weeks, from July 14 to August 2, he gradually reduced the intake of proteid food as well as the total amount of food consumed, doing this in part by diminishing the quantity eaten at breakfast, and in smaller measure at the two other meals of the day. During this period of two weeks, the urine and fæces were analyzed with the results shown in the accompanying table. Regarding the extent of proteid metabolism, it will be seen that the nitrogen content of the urine fell from 14.28 grams per day down to 5 to 6 grams per day. Having reached this level, the subject maintained it throughout the summer of 1903, occasional analyses being made to demonstrate the level of nitrogen excretion.
| Date. | Body- weight. | Urine. | Fæces. | Total Nitrogen. | |||||
|---|---|---|---|---|---|---|---|---|---|
| Volume. | Sp. Gr. | Nitrogen. | Moist. | Dry. | Nitrogen. | ||||
| 1903. | c.c. | grams. | grams. | grams. | grams. | grams. | |||
| July | 14 | 67.6 | 1300 | 1018 | 14.28 | 156.0 | 30.5 | 1.59 | 15.8 |
| 15 | 67.6 | 1095 | 1020 | 11.72 | 70.0 | 17.0 | 0.80 | 12.52 | |
| 16 | 67.1 | 860 | 1021 | 11.72 | 182.5 | 44.5 | 2.12 | 13.84 | |
| 17 | 66.9 | 675 | 1022 | 9.39 | 134.0 | 43.0 | 2.05 | 11.44 | |
| 18 | 66.3 | 865 | 1021 | 10.45 | 57.5 | 20.0 | 0.95 | 11.40 | |
| 19 | 65.7 | 785 | 1021 | 10.34 | 170.0 | 41.0 | 1.95 | 12.29 | |
| 20 | 65.7 | 740 | 1024 | 10.34 | 76.0 | 35.0 | 1.66 | 12.00 | |
| 21 | 65.7 | 910 | 1017 | 11.61 | 96.0 | 32.0 | 1.52 | 13.13 | |
| 22 | 65.7 | 900 | 1013 | 9.50 | 56.0 | 31.0 | 1.75 | 11.25 | |
| 23 | 65.3 | 600 | 1017 | 8.65 | 41.0 | 14.0 | 0.79 | 9.35 | |
| 24 | 65.0 | 640 | 1013 | 6.65 | 151.0 | 33.0 | 1.86 | 8.51 | |
| 25 | 65.3 | 690 | 1012 | 6.01 | 86.0 | 29.0 | 1.63 | 7.64 | |
| 26 | 65.3 | 410 | 1023 | 6.65 | 57.0 | 19.0 | 1.06 | 7.71 | |
| 27 | 65.7 | 530 | 1017 | 6.75 | 202.0 | 33.0 | 1.86 | 8.61 | |
| 28 | 65.7 | 610 | 1013 | 5.49 | 155.0 | 26.0 | 1.46 | 6.95 | |
| 29 | 66.4 | 620 | 1017 | 5.96 | 121.0 | 26.0 | 1.46 | 7.42 | |
| 30 | 66.3 | 700 | 1016 | 5.80 | 233.0 | 48.0 | 2.71 | 8.51 | |
| 31 | 65.8 | 1265 | 1010 | 6.70 | 211.0 | 36.0 | 2.03 | 8.73 | |
| Aug. | 1 | 65.3 | 1240 | 1009 | 6.23 | 172.0 | 23.0 | 1.29 | 7.52 |
| 2 | 65.3 | 760 | 1016 | 6.75 | 214.0 | 27.0 | 1.42 | 8.17 | |
| 11 | 65.3 | 500 | 1017 | 6.44 | 152.0 | 22.0 | 1.34 | 7.78 | |
| 12 | 65.3 | 405 | 1024 | 6.86 | 70.0 | 15.0 | 0.91 | 7.77 | |
| 13 | 65.3 | 540 | 1019 | 6.23 | 90.0 | 10.0 | 0.61 | 6.84 | |
In connection with the accompanying table of results, attention is called to the composition of the fæces with special reference to their content of nitrogen. The point to be emphasized is the gradual increase in the percentage content of fæcal nitrogen, associated with the changed diet and the general diminution of food intake. This is well illustrated by the following figures, giving the percentage of nitrogen in the dry fæces for the three periods of July 14-21, July 22-30, and August 11-13:
| July 14-21, | 4.77 | per | cent | Nitrogen |
| July 22-30, | 5.65 | ” | ” | ” |
| Aug. 11-13, | 6.11 | ” | ” | ” |
The diminished amount of fæcal discharge means naturally not only a smaller intake of food, but implies also a greater utilization of the food ingested, and as a result the increased percentage of nitrogen in the discharges shows itself because of the relatively larger preponderance of nitrogenous secretions from the intestinal tract.
The latter part of September, 1903, Dr. Underhill attempted to return to his original methods of living, but found difficulty in consuming the daily quantities of food he had formerly been in the habit of taking. From October 11 to October 25, 1903, however, he raised the consumption of proteid food to such a degree that the nitrogen excretion through the urine averaged from 10 to 12 grams per day. After this date he fell back to the lower proteid intake, and from that period to June 23, 1904, he maintained a low level of proteid metabolism without detriment to his bodily vigor, and, as he believes, with a distinct betterment.
The following tables of results extending from October 11, 1903, to June 23, 1904, show the data collected.