Part 9
Orange 100 × 0.20 = 0.200 grams. Bread rolls 37 × 1.64 = 0.607 Rice 50 × 0.36 = 0.180 Syrup 25 × 0.024 = 0.006 Coffee 125 × 0.06 = 0.075 Sugar 21 × 0.00 = 0.000 Cream 50 × 0.45 = 0.225 Bread 77 × 1.66 = 1.278 Celery soup 125 × 0.48 = 0.600 Mashed potato 270 × 0.26 = 0.702 Tomato sauce 50 × 0.23 = 0.115 Farina croquette 191 × 0.74 = 1.413 Syrup 78 × 0.024 = 0.019 Coffee 75 × 0.06 = 0.045 Cream 20 × 0.45 = 0.090 Sugar 7 × 0.00 = 0.000 Bread 49 × 1.82 = 0.892 Tomato soup 200 × 0.19 = 0.380 French fried potato 200 × 0.46 = 0.920 Spinach 50 × 0.54 = 0.270 Farina croquette 276 × 0.76 = 2.098 Syrup 100 × 0.024 = 0.024 Coffee 100 × 0.06 = 0.060 Sugar 14 × 0.00 = 0.000 Cream 50 × 0.45 = 0.225 ------ Total nitrogen in food 10.424 grams. Total nitrogen in urine 6.390
Fuel value of the food 3229 calories.
NITROGEN BALANCE.—_Mendel._
Nitrogen Output. Taken in. Nitrogen in Urine. Weight of Fæces (dry).
May 18 8.668 grams. 6.06 grams. 14 grams. 19 6.474 7.17 39 20 6.691 6.33 30 ------ 21 8.345 6.78 83 contain 6.06% N = 5.03 grm. N. 22 7.015 5.70 23 9.726 5.75 38 24 10.424 6.39 57 ------ ------ ------ 95 contain 5.76% N = 5.47 grm. N. ------ 10.50 grm. N. 57.343 44.18 + 10.50 grams nitrogen. ------ ---------------------- 57.343 grams nitrogen. 54.68 grams nitrogen.
Nitrogen balance for seven days = +2.663 grams. Nitrogen balance per day = +0.380 gram.
Average Intake.
Calories per day 2448. Nitrogen per day 8.192 grams.
In this period of seven days the average daily intake of nitrogen was 8.192 grams, or only 0.36 gram per day more than in the first balance period, while the average fuel value of the food amounted to 2448 calories per day. Yet the average daily output of nitrogen through the urine for this period was 6.31 grams, or 1.2 grams per day less than in the first balance experiment. Further, under the conditions of this balance experiment, the body was laying up 0.380 gram of nitrogen per day, _i. e._, showing a plus balance of 2.66 grams of nitrogen for the seven days’ period. Again, it is to be noted that the average daily amount of nitrogen metabolized, 6.31 grams, was 0.22 gram less than the average daily nitrogen excretion for the entire seven months’ period, 6.53 grams. Evidently, this subject was quite able to maintain nitrogen equilibrium with a metabolism of only 6.31 grams of nitrogen per day, on a daily diet having a fuel value of about 2400 calories. Indeed, taking into account the amount of the plus nitrogen balance, it is evident that the daily food was somewhat in excess of the real requirements of the body, under the then existing conditions of body-weight and bodily activity.
Again, we would call attention to the thorough utilization of the food in this experiment, emphasizing at the same time the voluminous character of the diet, together with its largely vegetable nature. The contrast between the diet made use of by Dr. Mendel and that used by the subject of the first experiment is quite striking, since the latter employed a much more concentrated diet with an average fuel value of only 1600 calories. Yet with a total intake of 57.343 grams of nitrogen for the seven days of Dr. Mendel’s balance period, 10.5 grams only passed out through the rectum, or 18.3 per cent, while in the second nitrogen balance of the first subject, with the more concentrated diet, 17.1 per cent of the total ingested nitrogen appeared in the fæces. In view of the great divergence in the character and volume of the intake, it is rather remarkable there should be so little difference in the relative utilization of the two diets.
Finally, taking the average daily excretion of nitrogen through the kidneys from November 10 to June 23, as a measure of the nitrogen metabolized daily, viz., 6.53 grams, and taking the body-weight at 70 kilos, it is plain to see that the nitrogen metabolized per kilo of body-weight throughout this experiment was 0.093 gram, closely similar to the result obtained with the first subject. In other words, both of these subjects, though widely different in body-weight, under different degrees of physical activity, and living on different forms of diet, seemingly required for the maintenance of equilibrium essentially the same amount of nitrogen per kilo of body-weight; viz., with the first subject 0.0947 gram, if we take the lower figure of the last two months, and 0.093 gram with the second subject.
Regarding the fuel value of the daily food, Dr. Mendel with a body-weight of 70 kilos, during the second balance period, apparently utilized on an average 34.9 calories per kilo of body-weight daily, while the first subject, of 57 kilos body-weight, made use of only 28 calories per kilo. The fuel value of the daily food must, however, as is well known, vary greatly with differing degrees of physical activity, from which arises the necessity for corresponding variation in the amounts of non-nitrogenous foods ingested.
* * * * *
Dr. Frank P. Underhill, instructor in physiological chemistry in the Sheffield Scientific School, is another subject of experiment who volunteered to study on himself the effects of a lowered proteid intake. Prior to the experiment he was in the habit of eliminating from 16 to 16.5 grams of nitrogen per day through the kidneys, representing the usual 105 grams of proteid food metabolized.
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.
+-------+-------+-----------------------+-----------------------+-------+ | | Body- | Urine. | Fæces. | Total | | Date. |weight.+-------+-----+---------+------+------+---------+ Nitro-| | | |Volume.| Sp. |Nitrogen.|Moist.| Dry. |Nitrogen.| gen. | | | | | Gr. | | | | | | +-------+-------+-------+-----+---------+------+------+---------+-------+ | 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.
UNDERHILL.