Chapter I: Experiments with Professional Men (2)

Nitrogen Output.
Taken in. Nitrogen in Urine. Weight of Fæces (dry).

June 23 6.622 grams. 5.26 grams. 10.6 grams.
24 6.331 5.30 0.7
25 4.941 4.43 14.2
26 5.922 4.66 11.9
27 5.486 4.98 15.2
------ ------ ------
82.6 grams contain 6.08% N.
29.302 24.63 + 5.022 grams nitrogen.
------ ----------------------
29.302 grams nitrogen. 29.652 grams nitrogen.

Nitrogen balance for five days = -0.350 gram.
Nitrogen balance per day = -0.070 gram.

Average Intake.

Calories per day 1549.
Nitrogen per day 5.860 grams.

Examination of these figures makes quite clear that the body was still in nitrogen equilibrium, or essentially so, the minus balance being so small as to have little significance. The body-weight was still stationary, and yet during this balance period the average daily intake of nitrogen was only 5.86 grams, corresponding to 36.62 grams of proteid or albuminous food. Further, the average daily fuel value of the food was only 1549 calories, a trifle less than in the preceding period. The average daily output of nitrogen through the urine for this period was 4.92 grams, corresponding to the metabolism of 30.7 grams of proteid food. Hence, the results of this period confirm those of the preceding period and make it quite clear that this subject, with a body-weight of 57.5 kilos, can be maintained in body equilibrium, and in nitrogen equilibrium, on a daily diet containing only 5.8 grams of nitrogen and with a fuel value of about 1600 calories. Under these conditions, as in the last balance period, the daily amount of nitrogen metabolized was very small, averaging only 4.92 grams. Comparison of this figure with the accepted standard of 16 grams of nitrogen makes quite clear the extent of the physiological economy which is attainable by the body, and emphasizes also the extent of the unnecessary and worse than useless labor put upon the body by the prevalent dietetic habits of the majority of mankind.

It is of course understood that the low fuel value which sufficed to keep the writer in body equilibrium would not meet the requirements of a more active life, with greater physical labor. The writer has led a very busy life during the year of this experiment, but it has been mental activity rather than physical, although doubtless he has exercised as much as the ordinary professional worker not accustomed to athletic sports. The results of the experiment, however, make it quite clear that a man of the above body-weight, even though he lead a very active life—not involving great physical labor—can maintain his body in equilibrium indefinitely with an intake of 36 to 40 grams of proteid or albuminous food, and with a total fuel value of about 1600 calories. Further, it is to be understood that there is no special form of diet involved in the accomplishment of such a result. Scrutiny of the daily diet, tabulated in the two balance periods, will show the character of the food made use of. Personal likes and dislikes must naturally enter into the choice of any diet, and freedom of choice, freedom to follow the dictates of one’s appetite, with such regulation as comes from the use of reason and intelligence, are all that is necessary to secure the desired end. Physiological economy in nutrition is easily attainable and does not involve the adoption of vegetarianism. It does mean, however, temperance and simplicity in diet, coupled with intelligent regulation, which, however, soon becomes a habit and eventually leads to a moderation in diet which fully satisfies all the cravings of appetite as completely as it suffices to maintain the body in equilibrium and in a general condition of health and vigor.

Taking the data recorded above, we may now calculate the nitrogen requirement of the body per kilo of body-weight. With the body-weight placed at 57 kilos and with an average daily elimination of nitrogen for nearly nine months of 5.699 grams, or practically 5.7 grams, it is evident that the nitrogen metabolized per kilo of body-weight in the present instance was exactly 0.1 gram. If we take the lower figure of 5.40 grams of nitrogen, the average daily excretion from April 13 to June 27, we find the nitrogen requirement to be 0.0947 gram per kilo of body-weight. Translating these figures into terms of proteid or albuminous matter, they mean the utilization or metabolism of 0.625 gram of proteid matter daily per kilo of body-weight, under the conditions of life, activity, and general food consumption prevailing throughout this period of nearly nine months with this particular individual.

Whether we are justified in saying that this figure represents the _minimal_ proteid requirement of this particular individual is perhaps questionable, since the proteid or nitrogen requirement will of necessity vary somewhat with the amount of non-nitrogenous food consumed. Doubtless, the nitrogen metabolism could be reduced still lower by increasing the intake of non-nitrogenous food, but under the above conditions of life, following a plan of living both congenial and satisfactory, one that fully sufficed to keep the body in equilibrium and with the practice of a general physiological economy, we may say that the metabolism of 0.1 gram of nitrogen per kilo of body-weight was quite sufficient to meet all the requirements of the body. Health, strength, mental and physical vigor have been maintained unimpaired, and there is a growing conviction that in many ways there is a distinct improvement in both the physical and mental condition. Greater freedom from fatigue, greater aptitude for work, greater freedom from minor ailments, have gradually become associated in the writer’s mind with this lowered proteid metabolism and general condition of physiological economy. The writer, however, is fully alive to the necessity of caution in the acceptance of one’s feelings as a measure of physical or mental condition, but he has been keenly watchful for any and every sign or symptom during the course of these experiments, and is now strongly of the opinion that there is much good to be gained in the adoption of dietetic habits that accord more closely with the true physiological needs of the body. If a man of 57 kilos body-weight can maintain a condition of equilibrium, with continuance of health, strength, and vigor (to say nothing of possible improvement), with a daily consumption of say 40 grams of proteid food and sufficient non-nitrogenous food to yield 2000 calories, why should he load up his system each day with three times this amount of proteid food, with enough more fat and carbohydrate to yield 3000 plus calories?

Finally, the writer in summing up his own experience is inclined to say that while he entered upon this experiment simply with a view to studying the question from a purely scientific and physiological standpoint, he has become so deeply impressed with the great gain to the body by this practice of physiological economy, and his system has become so accustomed to the new level of nutrition that there is no desire to return to the more liberal dietetic habits of former years.

* * * * *

Obviously, it is not wise nor safe to draw too broad deductions from a single individual, nor from a single experiment even though it extends over a long period of time; consequently, we may turn our attention to other individuals with presumably different personality and different habits of life. The writer’s colleague, Dr. Lafayette B. Mendel, Professor of Physiological Chemistry in the Sheffield Scientific School, kindly volunteered to become a subject of experiment. With a body-weight of 76 kilos, 32 years of age, and of strong physique, he commenced to modify his diet about the middle of October, 1903, diminishing gradually the amount of proteid food with the results shown in the following tables, where are given, as in the preceding experiment, the amounts of nitrogen in the urine, as a measure of the quantity of proteid metabolized, uric acid, and other factors of interest in this connection.

The collection of data commenced on October 26, 1903. During some weeks the urine of each day was not analyzed by itself, but an aliquot part was taken from the 24 hours’ quantity, and at the end of a week the determinations were made on the mixture, thereby giving the average daily composition for the period. With Dr. Mendel, as in the writer’s case, there was no prescribing of food, but perfect freedom of choice. The appetite was satisfied each day, but with a gradual diminution of proteid food, especially of meat. Dr. Mendel appeared to accomplish the desired end best by keeping up a liberal allowance of non-nitrogenous food, and the total potential energy of the daily diet was not so greatly diminished as in the writer’s case. In other words, he appeared to need more food, but succeeded without great effort in reducing the proteid intake to nearly as low a level as in the preceding experiment. For the period of three months from January 4 to April 3, 1904, the average daily excretion of nitrogen amounted to 6.46 grams, which means the metabolism of 40.37 grams of proteid or albuminous food per day for this quarter of the year.

MENDEL.

+-----------+-------+--------------------------------------------------+
| | | |
| | | Urine. |
| | | |
| Date. | Body- +-------+------+-----------+-----------+-----------+
| |weight.|Volume.| Sp. | Nitrogen. | Uric Acid.| P₂O₅. |
| | | 24 | Gr. | | | |
| | |hours. | | | | |
+-----------+-------+-------+------+-----------+-----------+-----------+
| 1903 | kilos | c.c. | | grams | gram | grams |
| | | | | | | |
| Oct. 26 | 76.2 | 1310 | 1019 | 10.53 | | |
| 27 | 75.0 | 1650 | 1016 | 13.46 | 0.580 | 1.90 |
| 28 | 74.5 | 915 | 1023 | 11.03 | | |
| 29 | 74.5 | 825 | 1025 | 11.48 | 0.629 | 1.87 |
| 30 | 74.6 | 1330 | 1018 | 13.17 | | |
| 31 | 74.5 | 1045 | 1021 | 12.37 | | |
| Nov. 1 | 74.5 | 1030 | 1020 | 10.38 | 0.602 | 1.59 |
| 2 | | 1080 | 1017 | 9.59 | | |
| 3 | 74.5 | 1058 | 1016 | 8.86 | 0.528 | 1.63 |
| 4 | 74.5 | 975 | 1019 | 8.66 | | |
| 5 | 74.5 | 1030 | 1021 | 8.90 | 0.514 | 1.83 |
| 6 | | 1230 | 1015 | 8.11 | | |
| 7 | 74.6 | 1450 | 1016 | 8.18 | | |
| 8 | 74.0 | 970 | 1019 | 7.91 | 0.424 | 1.92 |
| 9 | 74.0 | 620 | 1028 | 7.72 | | |
| 10 | 74.0 | 543 | 1027 | 6.60 | 0.390 | 1.17 |
| 11 | 74.0 | 1160 | 1016 | 7.03 | | |
| 12 | 74.0 | 863 | 1024 | 5.37 | 0.422 | 1.52 |
| 13 | 74.0 | 1410 | 1015 | 8.12 | | |
| 14 | 74.0 | 1265 | 1017 | 8.04 | 0.494 | 1.94 |
| 16 | 74.0 | 760 | 1021 | 6.93 | | |
| 17 | 74.0 | 850 | 1021 | 7.34 | 0.393 | 1.50 |
| 18 | 74.0 | 757 | 1020 | 6.84 | 0.364 | |
| 19 | 74.0 | 720 | 1025 | 7.35 | 0.456 | 1.25 |
| 20 | 74.0 | 655 | 1027 | 7.23 | 0.474 | |
| 21 | 74.0 | 985 | 1021 | 7.44 | 0.397 | |
| 22 | 74.5 | 590 | 1026 | 7.65 | 0.395 | 1.20 |
| 23 | 74.5 | 1100 | |⎫ | | |
| 24 | 74.0 | 1200 | 1017 |⎪ | | |
| 25 | | 1030 | |⎪ | | |
| 26 | 74.0 | 850 | |⎬ 7.00 | 0.410 | 1.72 |
| 27 | | 935 | 1020 |⎪ daily | daily | daily |
| 28 | 74.5 | 870 | 1021 |⎪ average | average | average |
| 29 | 74.5 | 993 | 1017 |⎭ | | |
| 30 | 74.5 | 650 | 1023 |⎫ | | |
| Dec. 1 | 74.5 | 960 | 1018 |⎪ | | |
| 2 | | 790 | 1023 |⎪ | | |
| 3 | 74.0 | 880 | 1023 |⎬ 7.28 | 0.480 | 1.80 |
| 4 | | 1200 | 1016 |⎪ | | |
| 5 | 74.0 | 930 | 1021 |⎪ | | |
| 6 | | 1080 | 1019 |⎭ | | |
| 7 | 73.5 | 790 | 1023 |⎫ | | |
| 8 | 73.5 | 965 | 1025 |⎪ | | |
| 9 | 74.0 | 1130 | 1017 |⎪ | | |
| 10 | 73.0 | 630 | 1031 |⎬ 7.63 | 0.438 | 1.91 |
| 11 | 73.0 | 925 | 1019 |⎪ | | |
| 12 | | 1395 | 1014 |⎪ | | |
| 13 | 73.0 | 1010 | 1018 |⎭ | | |
| 14 | | 1030 | 1020 | 7.73 | | |
| 15 | 73.0 | 875 | 1021 | 7.88 | | |
| 16 | | 625 | 1027 | 6.48 |⎫ | |
| 17 | | 700 | 1027 | 7.60 |⎪ | |
| 18 | | 880 | 1022 | 8.39 |⎪ | |
| 19 | | 935 | 1020 | 7.68 |⎪ | |
| 20 | | 1075 | 1019 | 7.35 |⎪ | |
| 21 | | 523 | 1032 | 6.37 |⎬ 0.259 | 1.10 |
| 22 | | 1455 | 1017 | 8.99 |⎪ | |
| 23 | | 920 | 1021 | 8.33 |⎪ | |
| 24 | | 725 | 1025 | 8.56 |⎪ | |
| 25 | | 865 | 1024 | 8.51 |⎪ | |
| 26 | | 710 | 1027 | 7.54 |⎭ | |
| 27 | | 910 | 1026 |⎫ | | |
| 28 | | 830 | 1026 |⎪ | | |
| 29 | | 730 | 1027 |⎪ | | |
| 30 | | 670 | 1033 |⎪ | | |
| 31 | | 630 | |⎬ 7.64 | 0.438 | 1.16 |
| 1904 | | | |⎪ | | |
| Jan. 1 | | 550 | |⎪ | | |
| 2 | | 1030 | 1022 |⎪ | | |
| 3 | | 1020 | 1019 |⎭ | | |
| 4 | | 750 | 1021 | 5.63 |⎫ | |
| 5 | | 1030 | 1016 | 5.31 |⎪ | |
| 6 | 73.0 | 815 | 1023 | 5.77 |⎪ | |
| 7 | 72.7 | 930 | 1019 | 6.02 |⎬ 0.436 | 1.41 |
| 8 | 73.5 | 1135 | 1017 | 5.72 |⎪ | |
| 9 | 72.2 | 995 | 1020 | 6.39 |⎪ | |
| 10 | | 1175 | 1017 | 6.84 |⎭ | |
| 11 | 72.0 | 1050 | 1017 | 6.17 |⎫ | |
| 12 | 72.2 | 1230 | 1015 | 6.71 |⎪ | |
| 13 | 71.8 | 1250 | 1016 | 7.43 |⎬ 0.443 | 1.43 |
| 14 | 71.8 | 1140 | 1015 | 7.05 |⎪ | |
| 15 | | 965 | 1019 | 5.99 |⎪ | |
| 16 | | 860 | 1023 | 6.71 |⎭ | |
| 17 | | 1030 | 1018 | 5.81 |⎫ | |
| 18 | | 730 | 1028 | 5.74 |⎪ | |
| 19 | | 825 | 1023 | 6.58 |⎪ | |
| 20 | | 1035 | 1021 | 6.70 |⎪ | |
| 21 | | 725 | 1030 | 6.96 |⎬ 0.465 | 1.48 |
| 22 | | 815 | 1023 | 6.99 |⎪ | |
| 23 | | 950 | 1018 | 6.27 |⎪ | |
| 24 | 71.6 | 790 | 1025 | 5.93 |⎭ | |
| 25 | 71.3 | 740 | 1027 | 5.33 |⎫ | |
| 26 | | 600 | 1030 | 5.44 |⎪ | |
| 27 | | 965 | 1020 | 6.89 |⎪ | |
| 28 | | 1045 | 1015 | 6.33 |⎬ 0.429 | 1.29 |
| 29 | | 895 | 1017 | 6.28 |⎪ | |
| 30 | 70.6 | 660 | 1027 | 6.53 |⎪ | |
| 31 | | 905 | 1021 | 6.79 |⎭ | |
| Feb. 1 | 71.7 | 695 | 1025 | 5.13 |⎫ | |
| 2 | | 950 | 1023 | 6.84 |⎪ | |
| 3 | | 1210 | 1019 | 8.10 |⎪ | |
| 4 | 71.5 | 985 | 1020 | 6.74 |⎬ 0.451 | 1.40 |
| 5 | | 1155 | 1020 | 6.51 |⎪ | |
| 6 | 71.1 | 1035 | 1019 | 6.27 |⎪ | |
| 7 | 70.8 | 760 | 1025 | 6.98 |⎭ | |
| 8 | 70.5 | 800 | 1022 | 6.29 | | |
| 9 | 70.6 | 1150 | 1023 | 7.52 | 0.448 | |
| 10 | 70.4 | 770 | 1022 | 6.75 | 0.318 | |
| 11 | 69.2 | 520 | 1031 | 6.71 | 0.458 | |
| 12 | 69.4 | 565 | 1033 | 8.24 | 0.390 | |
| 13 | 69.4 | 560 | 1030 | 7.83 | 0.420 | |
| 14 | 69.2 | 690 | 1027 | 7.99 | 0.447 | |
| 15 | 69.5 | 680 | 1027 | 7.50 |⎫ | |
| 16 | | 995 | 1019 | 6.86 |⎪ | |
| 17 | | 1055 | 1018 | 5.63 |⎪ | |
| 18 | | 1185 | 1015 | 6.11 |⎬ 0.420 | |
| 19 | | 712 | 1025 | 5.72 |⎪ | |
| 20 | 70.5 | 1000 | 1021 | 7.38 |⎪ | |
| 21 | 70.6 | 1235 | 1014 | 5.93 |⎭ | |
| 22 | | 900 | 1018 | 6.16 |⎫ | |
| 23 | 70.2 | 840 | 1020 | 5.49 |⎪ | |
| 24 | | 875 | 1017 | 5.83 |⎪ | |
| 25 | 70.5 | 1450 | 1018 | 8.09 |⎬ 0.488 | |
| 26 | 70.2 | 1485 | 1015 | 6.68 |⎪ | |
| 27 | | 1300 | 1013 | 5.93 |⎪ | |
| 28 | 69.2 | 735 | 1022 | 5.91 |⎭ | |
| 29 | | 575 | 1030 | 6.21 |⎫ | |
| Mar. 1 | | 975 | 1019 | 7.51 |⎪ | |
| 2 | 70.5 | 1240 | 1015 | 7.29 |⎪ | |
| 3 | | 1400 | 1013 | 6.63 |⎬ 0.462 | |
| 4 | 70.2 | 1375 | 1016 | 7.34 |⎪ | |
| 5 | 69.9 | 1100 | 1017 | 7.06 |⎪ | |
| 6 | 70.0 | 960 | 1020 | 6.51 |⎭ | |
| 7 | 70.5 | 970 | 1017 | 5.53 |⎫ | |
| 8 | 70.9 | 1220 | 1015 | 5.56 |⎪ | |
| 9 | 70.9 | 1285 | 1015 | 5.70 |⎪ | |
| 10 | | 1000 | 1020 | 6.24 |⎬ 0.413 | |
| 11 | 70.8 | 1120 | 1017 | 5.98 |⎪ | |
| 12 | | 1285 | 1015 | 6.55 |⎪ | |
| 13 | 70.4 | 1110 | 1015 | 5.79 |⎭ | |
| 14 | 70.0 | 690 | 1024 | 5.92 |⎫ | |
| 15 | 70.6 | 1240 | 1017 | 7.29 |⎪ | |
| 16 | 70.8 | 1450 | 1016 | 7.47 |⎪ | |
| 17 | 70.2 | 780 | 1022 | 6.41 |⎬ 0.485 | |
| 18 | | 1230 | 1012 | 6.57 |⎪ | |
| 19 | 70.1 | 780 | 1027 | 6.41 |⎪ | |
| 20 | | 950 | 1020 | 6.21 |⎭ | |
| 21 | 70.7 | 1005 | 1020 | 6.36 |⎫ | |
| 22 | 70.9 | 1525 | 1014 | 6.50 |⎪ | |
| 23 | 70.6 | 825 | 1023 | 6.39 |⎪ | |
| 24 | 70.4 | 550 | 1029 | 6.07 |⎬ 0.527 | |
| 25 | | 1070 | 1018 | 6.93 |⎪ | |
| 26 | 70.8 | 1100 | 1017 | 6.40 |⎪ | |
| 27 | 70.6 | 1115 | 1016 | 5.82 |⎭ | |
| 28 | 70.2 | 1185 | 1015 | 6.22 |⎫ | |
| 29 | 70.5 | 1370 | 1014 | 6.58 |⎪ | |
| 30 | 70.3 | 1185 | 1016 | 6.26 |⎬ 0.389 | |
| 31 | 70.3 | 1325 | 1013 | 5.96 |⎪ | |
| Apr. 1 | | 1060 | 1016 | 6.30 |⎪ | |
| 2 | 70.6 | 1115 | 1016 | 6.42 |⎪ | |
| 3 | 70.3 | 1290 | 1013 | 6.39 |⎭ | |
| 4 | 70.0 | 845 | 1022 | 6.44 |⎫ | |
| 5 | | 1110 | 1020 | 6.39 |⎪ | |
| 6 | | 1055 | 1022 | 7.53 |⎪ | |
| 7 | | 575 | 1027 | 6.42 |⎬ 0.356 | 1.54 |
| 8 | | 650 | 1031 | 6.94 |⎪ | |
| 9 | | 795 | 1026 | 7.06 |⎪ | |
| 10 | | 1230 | 1020 | 7.01 |⎭ | |
| 11 | | 850 | 1021 | 5.61 |⎫ | |
| 12 | | 1005 | 1018 | 6.66 |⎪ | |
| 13 | | 695 | 1020 | 5.75 |⎪ | |
| 14 | 69.6 | 910 | 1027 | 5.79 |⎬ 0.419 | |
| 15 | 70.1 | 1000 | 1018 | 6.42 |⎪ | |
| 16 | 70.9 | 1590 | 1016 | 6.30 |⎪ | |
| 17 | 70.8 | 1250 | 1015 | 5.25 |⎭ | |
| 18 | 70.5 | 985 | 1020 | 5.79 |⎫ | |
| 19 | 70.7 | 1230 | 1016 | 5.90 |⎪ | |
| 20 | 70.5 | 1485 | 1014 | 5.70 |⎪ | |
| 21 | 70.1 | 1125 | 1023 | 7.09 |⎬ 0.453 | |
| 22 | 70.3 | 1665 | 1013 | 7.09 |⎪ | |
| 23 | 69.8 | 935 | 1023 | 6.06 |⎪ | |
| 24 | 69.7 | 1100 | 1018 | 6.07 |⎭ | |
| 25 | 69.6 | 935 | 1021 | 5.78 |⎫ | |
| 26 | 69.9 | 1000 | 1021 | 6.18 |⎪ | |
| 27 | 70.1 | 1295 | 1015 | 6.06 |⎪ | |
| 28 | 70.0 | 1425 | 1013 | 5.56 |⎬ 0.373 | |
| 29 | 70.2 | 990 | 1022 | 6.24 |⎪ | |
| 30 | 70.2 | 1100 | 1021 | 7.32 |⎪ | |
| May 1 | 70.0 | 1380 | 1014 | 5.96 |⎭ | |
| 2 | 69.8 | 1050 | 1016 | 5.35 |⎫ | |
| 3 | 69.8 | 700 | 1022 | 5.46 |⎪ | |
| 4 | 69.5 | 900 | 1019 | 6.48 |⎪ | |
| 5 | 69.6 | 750 | 1023 | 6.52 |⎬ 0.260 | |
| 6 | 69.7 | 1120 | 1019 | 7.26 |⎪ | |
| 7 | | 1010 | 1020 | 6.00 |⎪ | |
| 8 | | 1165 | 1015 | 6.01 |⎭ | |
| 9 | 69.7 | 880 | 1020 | 5.38 |⎫ | |
| 10 | 70.0 | 935 | 1019 | 5.22 |⎪ | |
| 11 | 69.6 | 1050 | 1017 | 6.05 |⎪ | |
| 12 | 69.8 | 950 | 1020 | 6.15 |⎬ 0.408 | |
| 13 | | 1060 | 1020 | 6.62 |⎪ | |
| 14 | 69.5 | 1520 | 1015 | 6.47 |⎪ | |
| 15 | 69.3 | 1345 | 1014 | 5.65 |⎭ | |
| 16 | 69.0 | 1230 | 1015 | 5.09 | | |
| 17 | 68.4 | 775 | 1019 | 5.11 | | |
| 18 | 69.2 | 660 | 1021 | 6.06 |⎫ | |
| 19 | 68.6 | 905 | 1018 | 7.17 |⎪ | |
| 20 | 69.4 | 685 | 1022 | 6.33 |⎪ | |
| 21 | 69.1 | 1142 | 1018 | 6.78 |⎪ | |
| 22 | 69.5 | 1055 | 1019 | 5.70 |⎬ 0.325 | |
| 23 | 69.6 | 1053 | 1018 | 5.75 |⎪ | |
| 24 | 69.8 | 895 | 1020 | 6.39 |⎪ | |
| 25 | 69.4 | 900 | 1018 | 6.05 |⎪ | |
| 26 | 69.7 | 725 | 1025 | 6.55 |⎪ | |
| 27 | 70.0 | 705 | 1026 | 7.36 |⎭ | |
| 28 | 71.0 | 1115 | 1020 | 8.23 |⎫ | |
| 29 | | 1370 | 1016 | 7.83 |⎬ 0.476 | |
| 30 | 69.7 | 740 | 1023 | 7.10 |⎭ | |
| 31 | | 1135 | 1017 | 5.93 | | |
| June 1 | | 1300 | 1018 | 6.86 | | |
| 2 | | 1420 | 1014 | 6.06 | | |
| 3 | 69.7 | 1447 | 1015 | 7.03 | | |
| 4 | | 1383 | 1016 | 5.97 | | |
| 5 | | 1530 | 1015 | 6.43 | | |
| 6 | | 870 | 1023 | 5.53 | | |
| 7 | | 1010 | 1013 | 4.91 | | |
| 8 | | 815 | 1019 | 5.53 | | |
| 9 | | 865 | 1019 | 6.59 | | |
| 10 | 69.7 | 1110 | 1015 | 6.36 | | |
| 11 | | 1410 | 1017 | 5.95 | | |
| 12 | 69.1 | 1510 | 1014 | 6.07 | | |
| 13 | | 1100 | 1016 | 5.94 | | |
| 14 | | 1090 | 1018 | 5.43 | | |
| 15 | | 1380 | 1017 | 6.46 | | |
| 16 | 70.0 | 1760 | 1014 | 6.55 | | |
| 17 | | 1755 | 1013 | 6.63 | | |
| 18 | | 1075 | 1026 | 6.06 | | |
| 19 | 70.0 | 1285 | 1016 | 6.55 | | |
| 20 | | 585 | 1022 | 5.44 | | |
| 21 | | 595 | 1024 | 6.93 | | |
| 22 | | 655 | 1023 | 7.07 | | |
| 23 | | 1230 | 1015 | 7.45 | | |
+-----------+-------+-------+------+-----------+-----------+-----------+
|Daily aver. from | | | | | |
| Nov. 10, 1903. | 1001 | 1020 | 6.53 | 0.419 | 1.46 |
+-------------------+-------+------+-----------+-----------+-----------+

From November 10, 1903, to June 23, 1904, a period of about seven months and a half, the average daily excretion of nitrogen through the urine was 6.53 grams. In other words, throughout this long period the average daily amount of proteid matter metabolized was 40.8 grams, only a little more than one-third the amount called for by the Voit standard. Until February, the body-weight gradually fell, but from the early part of February until the end of the experiment the body-weight remained practically stationary at 70 kilos. Dr. Mendel, however, from the necessities of his daily work in the laboratory was compelled to a much greater degree of physical activity than the subject of the preceding experiment, and consequently required a larger amount of non-nitrogenous food than the latter. Further, owing to his greater physical activity and the necessary variations in this daily activity, it was not so easy at first to attain equilibrium.

On February 9, a balance experiment of six days was commenced, with a careful comparison of the nitrogen intake and output. In the accompanying tables are shown all of the data. By scrutiny of these it will be seen that Dr. Mendel had adopted essentially a vegetarian diet. During this period of six days, however, he was not in nitrogen equilibrium, neither was he strictly in body equilibrium, since there was a distinct tendency for the body to fall off in weight. In this connection it may be mentioned that there is always a tendency during a balance experiment of this character for the subject to eat less than he is ordinarily accustomed to, owing to the tediousness of weighing every particle of food consumed. Further, for the same reason, and to avoid excess of chemical work in the analysis of samples of food, he is inclined to limit his diet to a few articles and thereby unconsciously restricts his intake of food, sometimes disastrously so.

_Tuesday, February 9, 1904._

Breakfast.—Bread 33 grams, sugar 20 grams, coffee and milk 210 grams.

Lunch.—Consommé 150 grams, sweet potato 170 grams, bread 135 grams, tomato 106 grams, coffee and milk 210 grams, sugar 20 grams.

Dinner.—Bread 75 grams, mashed potato 200 grams, string beans 91 grams, apple pie 282 grams, coffee and milk 210 grams, sugar 20 grams, water 100 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Bread 33 + 135 + 75 = 243 × 1.36 = 3.30 grams.
Sugar 20 + 20 + 20 = 60 × 0.00 = 0.00
Coffee (breakfast) 210 × 0.10 = 0.21
Consommé 150 × 0.38 = 0.57
Sweet potato 170 × 0.28 = 0.48
Tomato 106 × 0.19 = 0.20
Coffee (lunch) 210 × 0.15 = 0.32
Potato 200 × 0.36 = 0.72
String beans 91 × 0.26 = 0.24
Apple pie 282 × 0.49 = 1.38
Coffee (dinner) 210 × 0.099 = 0.21
------
Total nitrogen in food 7.63 grams.
Total nitrogen in urine 7.52

Fuel value of the food 2297 calories.

_Wednesday, February 10, 1904._

Breakfast.—Bread 37 grams, sugar 20 grams, coffee and milk 210 grams.

Lunch.—Bread 110 grams, sugar 7 grams, milk 250 grams, apple fritters 90 grams.

Dinner.—Bread 37 grams, sugar 21 grams, baked beans 100 grams, cranberry sauce 125 grams, coffee and milk 210 grams, molasses candy 54 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Bread 37 + 110 + 37 = 184 × 1.65 = 3.04 grams.
Sugar 20 + 7 + 21 = 48 × 0.00 = 0.00
Coffee (breakfast) 210 × 0.12 = 0.25
Milk 250 × 0.55 = 1.37
Apple fritters 90 × 0.45 = 0.40
Baked beans 100 × 1.40 = 1.40
Cranberry sauce 125 × 0.04 = 0.05
Coffee (dinner) 210 × 0.11 = 0.23
Candy 54 × 0.06 = 0.03
------
Total nitrogen in food 6.77 grams.
Total nitrogen in urine 6.75

Fuel value of the food 1673 calories.

_Thursday, February 11, 1904._

Breakfast.—Bread 40 grams, sugar 20 grams, coffee and milk 210 grams.

Lunch.—Bread 95 grams, sweet potato 130 grams, sugar 7 grams, milk 250 grams, peach preserve 93 grams.

Dinner.—Bread 90 grams, mashed potato 100 grams, tomato purée 135 grams, baked beans 75 grams, lemon pie 110 grams, coffee and milk 210 grams, sugar 21 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Bread 40 + 95 + 90 = 225 × 1.75 = 3.94 grams.
Sugar 20 + 7 + 21 = 48 × 0.00 = 0.00
Coffee (breakfast) 210 × 0.096 = 0.20
Sweet potato 130 × 0.31 = 0.40
Milk 250 × 0.51 = 1.27
Peach preserve 93 × 0.09 = 0.08
Potato 100 × 0.36 = 0.36
Tomato purée 135 × 0.33 = 0.45
Baked beans 75 × 1.30 = 0.98
Lemon pie 110 × 0.61 = 0.67
Coffee (dinner) 210 × 0.13 = 0.27
------
Total nitrogen in food 8.62 grams.
Total nitrogen in urine 6.71

Fuel value of the food 1828 calories.

_Friday, February 12, 1904._

Breakfast.—Bread 58 grams, sugar 21 grams, coffee and milk 210 grams.

Lunch.—Bread 120 grams, sugar 21 grams, custard 76 grams, milk 250 grams, coffee and milk 125 grams.

Dinner.—Bread 67.5 grams, sugar 21 grams, mashed potato 150 grams, lima beans 80 grams, coffee and milk 210 grams, apple dumpling 131 grams, molasses candy 27 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Bread 58 + 120 + 67.5 = 245.5 × 1.71 = 4.20 grams.
Sugar 21 + 21 + 21 = 63.0 × 0.00 = 0.00
Coffee (breakfast) 210.0 × 0.11 = 0.23
Custard 76.0 × 0.83 = 0.63
Milk 250.0 × 0.48 = 1.20
Coffee (lunch) 125.0 × 0.078 = 0.10
Potato 150.0 × 0.37 = 0.56
Lima beans 80.0 × 0.90 = 0.72
Coffee (dinner) 210.0 × 0.12 = 0.25
Apple dumpling 131.0 × 0.72 = 0.94
Candy 27.0 × 0.06 = 0.00
------
Total nitrogen in food 8.83 grams.
Total nitrogen in urine 8.24

Fuel value of the food 1929 calories.

_Saturday, February 13, 1904._

Breakfast.—Bread 47.5 grams, sugar 28 grams, coffee and milk 210 grams.

Lunch.—Bread 57 grams, sugar 40 grams, sweet potato 135 grams, quince preserve 73 grams, apple turnovers 118 grams, coffee and milk 310 grams.

Dinner.—Bread 59 grams, mashed potato 175 grams, peas 80 grams, apple pie 141.5 grams, sugar 21 grams, coffee and milk 210 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Bread 47.5 + 57 + 59 = 164.0 × 1.64 = 2.69 grams.
Sugar 28 + 40 + 21 = 89.0 × 0.00 = 0.00
Coffee (breakfast) 210.0 × 0.11 = 0.23
Sweet potato 135.0 × 0.37 = 0.50
Quince preserve 73.0 × 0.047 = 0.03
Apple turnovers 118.0 × 0.96 = 1.13
Coffee (lunch) 310.0 × 0.15 = 0.47
Potato 175.0 × 0.37 = 0.65
Peas 80.0 × 0.96 = 0.77
Apple pie 141.5 × 0.43 = 0.61
Coffee (dinner) 210.0 × 0.11 = 0.23
------
Total nitrogen in food 7.31 grams.
Total nitrogen in urine 7.83

Fuel value of the food 2057 calories.

_Sunday, February 14, 1904._

Breakfast.—Bread 50 grams, sugar 21 grams, banana 92.5 grams, coffee and milk 210 grams.

Lunch.—Bread 108.5 grams, sugar 28 grams, baked potato 165 grams, apple sauce 114 grams, coffee and milk 210 grams.

Dinner.—Bread 63 grams, sugar 28 grams, succotash 75 grams, mashed potato 200 grams, chocolate layer cake 80 grams, ice cream 73 grams, coffee and milk 210 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Bread 50 + 108.5 + 63 = 221.5 × 1.75 = 3.87 grams.
Sugar 21 + 28 + 28 = 77.0 × 0.00 = 0.00
Banana 92.5 × 0.002 = 0.19
Coffee (breakfast) 210.0 × 0.11 = 0.23
Baked potato 165.0 × 0.41 = 0.68
Apple sauce 114.0 × 0.029 = 0.03
Coffee (lunch) 210.0 × 0.10 = 0.21
Succotash 75.0 × 0.57 = 0.43
Mashed potato 200.0 × 0.37 = 0.74
Chocolate cake 80.0 × 0.75 = 0.60
Ice cream 73.0 × 0.58 = 0.42
Coffee (dinner) 210.0 × 0.11 = 0.23
------
Total nitrogen in food 7.63 grams.
Total nitrogen in urine 7.99

Fuel value of the food 2065 calories.

NITROGEN BALANCE.—_Mendel._

Nitrogen Output.
Taken in. Nitrogen in Urine. Weight of Fæces (dry).

Feb. 9 7.63 grams. 7.52 grams.
10 6.77 6.75
11 8.62 6.71
12 8.83 8.24 53 ⎫ contain 5.84%
⎬ N = 6.248 grm. N.
13 7.31 7.83 54 ⎭
14 7.63 7.99 39.2 contain 6.72%
N = 2.634
------ ------ ------ -----
146.2 8.882 grm. N.
46.79 45.04 + 8.882 grams nitrogen.
------ ----------------------
46.79 grams nitrogen. 53.92 grams nitrogen.

Nitrogen balance for six days = -7.13 grams.
Nitrogen balance per day = -1.19 grams.

Average Intake.

Calories per day 1975.
Nitrogen per day 7.83 grams.

In this balance period of six days the average daily intake of nitrogen was 7.83 grams, coupled with an average fuel value of the food per day of 1975 calories. This latter value was obviously too small for a man of Dr. Mendel’s body-weight, and doing the amount of physical work he was called upon to perform. Being on one’s feet in a laboratory six to eight hours a day, in addition to the ordinary activity of a vigorous man leading a strenuous life, necessitates the utilization and oxidation of considerable food material. The average daily output of nitrogen through the urine amounted to 7.50 grams, considerably above the average daily excretion for the seven months’ period. Still, under these conditions there was a minus balance of 7.13 grams of nitrogen for the six days’ period, indicating that the body was drawing upon its stock of proteid material to the extent of 1.19 grams of nitrogen per day. This does not necessarily mean that the body had need of that additional amount of proteid matter each day, but rather that the amount of total energy required was beyond the potential energy supplied by the food. There not being sufficient non-nitrogenous food at hand, the body was compelled to draw upon its own resources, and in so doing utilized some of its tissue proteid. This is made quite clear by the results of the second balance period shortly to be described.

It is evident, however, that while the body was not in nitrogen equilibrium for this particular period of six days, there must have been a general condition of both body and nitrogen equilibrium, otherwise the body-weight would not have remained practically stationary for so long a period as from February 7 to June 20.

Commencing May 18, a second nitrogen balance was attempted, in which, as in the preceding case, there was a careful comparison of income and output for seven days. There was as before a free choice of food, but it was essentially vegetable in character. A greater variety of foods was taken, however, and an effort was made to have the non-nitrogenous food somewhat more liberal in amount, though in as close harmony as possible with the desires of the appetite.

_Wednesday, May 18, 1904._

Breakfast.—Banana 92 grams, bread rolls 28 grams, cream 50 grams, coffee 150 grams, sugar 21 grams.

Lunch.—Bread 66 grams, soup 150 grams, farina 154 grams, sweet potato 123 grams, beans 70 grams, syrup 50 grams, coffee 150 grams, cream 50 grams, sugar 14 grams.

Dinner.—Bread 42 grams, consommé 100 grams, spinach 100 grams, mashed potato 250 grams, apple pie 97 grams, coffee 150 grams, cream 50 grams, sugar 21 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Banana 92 × 0.23 = 0.212 grams.
Bread rolls 28 × 1.66 = 0.465
Cream 50 × 0.46 = 0.230
Coffee 150 × 0.066 = 0.099
Sugar 21 × 0.00 = 0.000
Bread 66 × 1.60 = 1.056
Soup 150 × 0.41 = 0.615
Farina 154 × 1.09 = 1.678
Sweet Potato 123 × 0.32 = 0.394
Beans 70 × 0.34 = 0.238
Syrup 50 × 0.024 = 0.012
Coffee 150 × 0.057 = 0.086
Cream 50 × 0.46 = 0.230
Sugar 14 × 0.00 = 0.000
Bread 42 × 1.80 = 0.756
Consommé 100 × 0.38 = 0.380
Spinach 100 × 0.53 = 0.530
Mashed potato 250 × 0.38 = 0.950
Apple pie 97 × 0.43 = 0.417
Coffee 150 × 0.06 = 0.090
Cream 50 × 0.46 = 0.230
Sugar 21 × 0.00 = 0.000
------
Total nitrogen in food 8.668 grams.
Total nitrogen in urine 6.060

Fuel value of the food 2359 calories.

_Thursday, May 19, 1904._

Breakfast.—Banana 102 grams, bread rolls 50 grams, coffee 150 grams, cream 50 grams, sugar 21 grams.

Lunch.—Bread 57 grams, egg omelette 20 grams, hominy 137 grams, syrup 68 grams, potatoes 128 grams, coffee 100 grams, sugar 21 grams, cream 50 grams.

Dinner.—Tomato purée 200 grams, bread 24 grams, fried sweet potato 100 grams, spinach 70 grams, Indian meal 100 grams, syrup 25 grams, coffee 100 grams, sugar 21 grams, cream 40 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Banana 102 × 0.23 = 0.235 grams.
Bread rolls 50 × 1.54 = 0.770
Coffee 150 × 0.06 = 0.090
Cream 50 × 0.47 = 0.235
Sugar 21 × 0.00 = 0.000
Bread 57 × 1.60 = 0.912
Egg Omelette 20 × 1.58 = 0.316
Hominy 137 × 0.20 = 0.274
Syrup 68 × 0.024 = 0.016
Potatoes 128 × 0.49 = 0.627
Coffee 100 × 0.06 = 0.060
Cream 50 × 0.47 = 0.235
Sugar 21 × 0.00 = 0.000
Tomato purée 200 × 0.53 = 1.060
Bread 24 × 1.74 = 0.418
Sweet potato 100 × 0.38 = 0.380
Spinach 70 × 0.56 = 0.392
Indian meal 100 × 0.20 = 0.200
Syrup 25 × 0.024 = 0.006
Coffee 100 × 0.06 = 0.060
Sugar 21 × 0.00 = 0.000
Cream 40 × 0.47 = 0.188
------
Total nitrogen in food 6.474 grams.
Total nitrogen in urine 7.170

Fuel value of the food 2072 calories.

_Friday, May 20, 1904._

Breakfast.—Sliced orange 140 grams, coffee 100 grams, cream 30 grams, sugar 21 grams.

Lunch.—Bread 28 grams, mashed potato 250 grams, lima beans 40 grams, coffee 100 grams, sugar 21 grams, cream 30 grams, fried hominy 115 grams, syrup 48 grams.

Dinner.—Bread 19 grams, consommé 150 grams, string beans 140 grams, mashed potato 250 grams, rice croquette 93 grams, cranberry jam 95 grams, coffee 100 grams, sugar 21 grams, cream 30 grams, syrup 25 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Sliced orange 140 × 0.20 = 0.280
Coffee 100 × 0.06 = 0.060
Cream 30 × 0.44 = 0.132
Sugar 21 × 0.00 = 0.000
Bread 28 × 1.71 = 0.479
Mashed potato 250 × 0.30 = 0.750
Lima beans 40 × 0.76 = 0.304
Coffee 100 × 0.06 = 0.060
Sugar 21 × 0.00 = 0.000
Cream 30 × 0.44 = 0.132
Fried hominy 115 × 0.57 = 0.656
Syrup 48 × 0.024 = 0.012
Bread 19 × 1.97 = 0.374
Consommé 150 × 0.59 = 0.885
String beans 140 × 0.36 = 0.504
Mashed potato 250 × 0.34 = 0.850
Rice croquettes 93 × 1.06 = 0.986
Cranberry jam 95 × 0.03 = 0.029
Coffee 100 × 0.06 = 0.060
Sugar 21 × 0.00 = 0.000
Cream 30 × 0.44 = 0.132
Syrup 25 × 0.024 = 0.006
------
Total nitrogen in food 6.691 grams.
Total nitrogen in urine 6.330

Fuel value of the food 1915 calories.

_Saturday, May 21, 1904._

Breakfast.—Banana 153 grams, coffee 150 grams, sugar 21 grams, cream 30 grams.

Lunch.—Bread 25 grams, potato croquette 229 grams, Indian meal 109 grams, tomato 123 grams, syrup 48 grams, coffee 100 grams, sugar 14 grams, cream 20 grams.

Dinner.—Bread 31 grams, bean soup 100 grams, fried potato 200 grams, bacon 5 grams, lettuce-orange salad 47 grams, prunes 137 grams, coffee 100 grams, sugar 21 grams, cream 25 grams, banana 255 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Banana 153 × 0.23 = 0.352 grams.
Coffee 150 × 0.06 = 0.090
Sugar 21 × 0.00 = 0.000
Cream 30 × 0.43 = 0.129
Bread 25 × 1.82 = 0.455
Potato croquette 229 × 0.71 = 1.626
Indian meal 109 × 1.09 = 1.188
Tomato 123 × 0.17 = 0.209
Syrup 48 × 0.024 = 0.012
Coffee 100 × 0.06 = 0.060
Sugar 14 × 0.00 = 0.000
Cream 20 × 0.43 = 0.086
Bread 31 × 1.62 = 0.502
Bean soup 100 × 1.21 = 1.210
Fried potato 200 × 0.60 = 1.200
Bacon 5 × 3.05 = 0.153
Lettuce-orange salad 47 × 0.21 = 0.099
Prunes 137 × 0.16 = 0.219
Coffee 100 × 0.06 = 0.060
Sugar 21 × 0.00 = 0.000
Cream 25 × 0.43 = 0.108
Banana 255 × 0.23 = 0.587
------
Total nitrogen in food 8.345 grams.
Total nitrogen in urine 6.780

Fuel value of the food 2485 calories.

_Sunday, May 22, 1904._

Breakfast.—Banana 220 grams, orange 60 grams, coffee 100 grams, sugar 21 grams, cream 25 grams.

Lunch.—Bread 35 grams, potato 300 grams, fried rice 160 grams, syrup 63 grams, ice cream 84 grams, coffee 100 grams, sugar 14 grams.

Dinner.—Cream of celery soup 100 grams, bread 21 grams, mashed potato 250 grams, spinach 40 grams, French fried potato 100 grams, strawberry short-cake 120 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Banana 220 × 0.23 = 0.506 grams.
Orange 60 × 0.20 = 0.120
Coffee 100 × 0.06 = 0.060
Sugar 21 × 0.00 = 0.000
Cream 25 × 0.45 = 0.113
Bread 35 × 1.57 = 0.550
Potato 300 × 0.30 = 0.900
Fried rice 160 × 0.75 = 1.200
Syrup 63 × 0.024 = 0.015
Ice cream 84 × 0.53 = 0.445
Coffee 100 × 0.06 = 0.060
Sugar 14 × 0.00 = 0.000
Cream of celery soup 100 × 0.33 = 0.330
Bread 21 × 1.91 = 0.401
Mashed potato 250 × 0.37 = 0.925
Spinach 40 × 0.55 = 0.220
French fried potato 100 × 0.57 = 0.570
Strawberry short-cake 120 × 0.50 = 0.600
------
Total nitrogen in food 7.015 grams.
Total nitrogen in urine 5.700

Fuel value of the food 2321 calories.

_Monday, May 23, 1904._

Breakfast.—Banana 229 grams, coffee 125 grams, sugar 21 grams, cream 25 grams.

Lunch.—Bread 58 grams, apple sauce 125 grams, scrambled egg 15 grams, consommé 75 grams, fried potato 170 grams, rice croquette 197 grams, syrup 68 grams, coffee 100 grams, sugar 21 grams, cream 30 grams.

Dinner.—Bread 72.5 grams, vegetable soup 100 grams, potato croquette 198 grams, bacon 7 grams, string beans 120 grams, water ice 77 grams, coffee 100 grams, cream 30 grams, sugar 14 grams, banana 270 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Banana 229 × 0.23 = 0.527 grams.
Coffee 125 × 0.06 = 0.075
Sugar 21 × 0.00 = 0.000
Cream 25 × 0.45 = 0.113
Bread 58 × 1.63 = 0.945
Apple sauce 125 × 0.02 = 0.025
Scrambled egg 15 × 2.07 = 0.311
Consommé 75 × 0.65 = 0.488
Fried potato 170 × 0.60 = 1.020
Rice croquette 197 × 0.61 = 1.202
Syrup 68 × 0.024 = 0.016
Coffee 100 × 0.06 = 0.060
Sugar 21 × 0.00 = 0.000
Cream 30 × 0.45 = 0.135
Bread 72.5 × 1.75 = 1.269
Soup 100 × 0.70 = 0.700
Potato croquette 198 × 0.77 = 1.525
Bacon 7 × 3.28 = 0.230
String beans 120 × 0.22 = 0.264
Water ice 77 × 0.006 = 0.005
Coffee 100 × 0.06 = 0.060
Cream 30 × 0.45 = 0.135
Sugar 14 × 0.00 = 0.000
Banana 270 × 0.23 = 0.621
------
Total nitrogen in food 9.726 grams.
Total nitrogen in urine 5.750

Fuel value of the food 2756 calories.

_Tuesday, May 24, 1904._

Breakfast.—Orange 100 grams, rolls 37 grams, rice 50 grams, syrup 25 grams, coffee 125 grams, sugar 21 grams, cream 50 grams.

Lunch.—Bread 77 grams, cream of celery soup 125 grams, mashed potato 270 grams, tomato sauce 50 grams, farina croquette 191 grams, syrup 78 grams, coffee 75 grams, cream 20 grams, sugar 7 grams.

Dinner.—Bread 49 grams, tomato soup 200 grams, French fried potato 200 grams, spinach 50 grams, farina croquette 276 grams, syrup 100 grams, coffee 100 grams, sugar 14 grams, cream 50 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

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.

* * * * *