Physiological economy in nutrition, with special reference to the minimal proteid requirement of the healthy man

I. EXPERIMENTS WITH PROFESSIONAL MEN.

Reading edition

Before proceeding with a detailed account of the experimental work, it may be well again to emphasize that what is especially desired is to ascertain how far, if any, the intake of proteid food can be diminished without detriment to the body, i. e., with maintenance of nitrogen and body equilibrium and without impairment of bodily and mental vigor. Further, if a lower proteid standard than that generally adopted can be established, it is desirable to ascertain whether it can be maintained indefinitely, or for a long period of time, without loss of strength and vigor. Obviously, it is of primary importance that we should know quite definitely what the minimal proteid requirement of the healthy man per kilo of body-weight really is, and the experimental work about to be detailed has aimed especially to determine whether it is possible to materially lower the amount of daily proteid food, without detriment to the bodily health and with maintenance of physical and mental vigor.

The writer, fully impressed with his responsibility in the conduct of an experiment of this kind, began with himself in November, 1902. At that time he weighed 65 kilos, was nearly 47 years of age, and accustomed to eating daily an amount of food approximately equal to the so-called dietary standards. Recognizing that the habits of a lifetime should not be too suddenly changed, a gradual reduction was made in the amount of proteid or albuminous food taken each day. In the writer’s case, this resulted in the course of a month or two in the complete abolition of breakfast, except for a small cup of coffee. A light lunch was taken at 1.30 P. M., followed by a heavier dinner at 6.30 P. M. Occasionally, however, the heartier meal was taken at noontime, as the appetite suggested. It should be added that the total intake of food was gradually diminished, as well as the proteid constituents. There was no change, however, to a vegetable diet, but a simple introduction of physiological economy. Still, there was and is now a distinct tendency toward the exclusion of meat in some measure, the appetite not calling for this form of food in the same degree as formerly. At first, this change to a smaller amount of food daily was attended with some discomfort, but this soon passed away, and the writer’s interest in the subject was augmented by the discovery that he was unquestionably in improved physical condition. A rheumatic trouble in the knee joint, which had persisted for a year and a half and which only partially responded to treatment, entirely disappeared (and has never recurred since). Minor troubles, such as “sick headaches” and bilious attacks, no longer appeared periodically as before. There was greater appreciation of such food as was eaten; a keener appetite and a more acute taste seemed to be developed, with a more thorough liking for simple foods. By June, 1903, the body-weight had fallen to 58 kilos.

During the summer the same simple diet was persisted in—a small cup of coffee for breakfast, a fairly substantial dinner at midday and a light supper at night. Two months were spent in Maine at an inland fishing resort, and during a part of this time a guide was dispensed with and the boat rowed by the writer frequently six to ten miles in a forenoon, sometimes against head winds (without breakfast), and with much greater freedom from fatigue and muscular soreness than in previous years on a fuller dietary. The test of endurance and fitness for physical work which the writer thus carried out “on an empty stomach” tended to strengthen the opinion that it is a mistake to assume the necessity for a hearty meal because heavy work is about to be done. It is certainly far more rational from a physiological standpoint to leave the hearty meal until the day’s work is accomplished. We seemingly forget that the energy of muscular contraction comes not from the food-stuffs present at the time in the stomach and intestinal tract, but rather from the absorbed material stored up in the muscles and which was digested and absorbed a day or two before. Further, it is to be remembered that the very process of digestion draws to the gastro-intestinal tract a large supply of blood, and that a large amount of energy is needed for the processes of secretion, digestion, absorption, and peristalsis, which are of necessity incited by the presence of food in the stomach and intestine, thereby actually diminishing the amount of energy available at the place where it is most needed. Why, then, draw upon the resources of the body just at a time, or slightly prior to the time, when the work we desire to perform, either muscular or mental, calls for a copious blood supply in muscle or brain, and when all available energy is needed for the task that is to be accomplished?

We are too wont to compare the working body with a machine, the boiler, engine, etc., overlooking the fact that the animal mechanism differs from the machine in at least one important respect. When we desire to set machinery in operation we must get up steam, and so a fire is started under the boiler and steam is generated in proportion as fuel is burned. The source of the energy made use of in moving the machinery is the extraneous combustible material introduced into the fire-box, but the energy of muscular contraction, for example, comes not from the oxidizable food material in the stomach, but from the material of the muscle itself. In other words, in the animal body it is a part of the tissue framework, or material that is closely incorporated with the framework, that is burned up, and the ability to endure continued muscular strain depends upon the nutritive condition of the muscles involved, and not upon the amount of food contained in, or introduced into, the stomach. All physiologists will, I think, acknowledge the soundness of this reasoning, but how few of us apply the principle in practice. It is perfectly logical to begin the work of the day with a comparatively empty stomach,—after we have once freed ourselves from the habit of a hearty breakfast,—and in the writer’s experience both mental and physical work have become the easier from this change of habit. The muscle and the brain are given opportunity to repair the waste they have undergone, by the taking of food at times when the digestive processes will not draw upon the energy that in activity is needed elsewhere.

Further, it is easy to understand why on a restricted diet, especially of proteid foods, there should be a diminished sense of fatigue in connection with vigorous or continued muscular work, and why at the same time there should be an increased power of endurance, with actual increase of strength. With a diminished intake of proteid food there is a decreased formation of crystalline nitrogenous waste products, such as uric acid and the purin bases, to say nothing of other bodies less fully known, which circulating through the system are undoubtedly responsible, in part at least, for what we term fatigue. We need not consider here whether the sense of fatigue is due to an action of these substances upon the muscles themselves, upon the motor nerves or their end-plates, or upon the central nervous system; it is enough for the present purpose to emphasize the probable results of their presence in undue amount. Lastly, we may emphasize what is pretty clearly evident to-day, viz., that the energy of muscular contraction comes preferably from the oxidation, not of the nitrogenous or proteid constituents of the muscles, but of the non-nitrogenous components of the tissue; another reason why excess of proteid food may be advantageously avoided. Moreover, proteid food stimulates body metabolism in general, and hence undue amounts of proteid in the diet augment unnecessarily the metabolism or combustion of the non-nitrogenous material of the muscle, thereby destroying what would otherwise be preserved as a source of energy in muscular contraction, when the muscles are called upon for the performance of their daily functions.

On the writer’s return to New Haven in the fall of 1903, he was surprised to find that his body-weight was practically the same as early in July. In the period between November, 1902, and July, 1903, the body had lost 8 kilos under the gradual change of diet, but from July to October, 1903, the weight had apparently remained stationary, from which it might fairly be assumed that the body had finally adjusted itself to the new conditions.

What now was the condition of the body as regards nitrogen metabolism? To answer this question the entire twenty-four hours’ urine was collected practically every day, from October 13, 1903, to June 28, 1904, representing a period of nearly nine months. This daily output through the kidneys was analyzed each day with special reference to the total nitrogen,[31] as a measure of the amount of proteid material metabolized. Total volume of the urine, specific gravity, uric acid, phosphoric acid, indican, and other points were also considered, the more important results being indicated in the following tables.

CHITTENDEN.

Date. Body-weight. Urine.

Volume. 24 hours. Sp. Gr. Nitrogen. Uric Acid. P₂O₅.

1903 kilos c.c. grams gram grams

Oct. 13 57.5 380 1027 5.46 0.376 1.10

14 550 1027 6.51

15 400 1022 5.40 0.352 1.02

16 500 1027 6.45

17 57.4 477 1030 6.40

18 670 1027 7.20 0.406 1.10

19 435 1027 6.13

20 465 1028 6.83 0.476 0.92

21 450 1029 6.51

22 465 1027 6.14 0.370 0.96

27 445 1023 5.52 0.385 0.79

28 405 1027 5.08

Nov. 1 390 1029 5.68 0.372 0.42

2 530 1027 6.33

3 470 1027 5.92 0.412 0.75

4 425 1028 5.88

5 375 1029 4.93 0.330 0.79

7 545 1028 6.57

8 57.4 456 1029 5.82 0.371 0.65

9 415 1027 5.43

10 615 1025 6.45 0.430 1.17

11 410 1028 4.80

12 580 1026 5.64 0.371 1.02

13 584 1027 5.82

14 505 1029 6.36

15 405 1028 5.80 0.384 0.73

16 425 1027 5.43

17 455 1028 5.27 0.367 0.76

18 575 1027 6.62

19 447 1027 5.34 0.389 0.77

20 480 1029 6.00

21 57.5 400 1029 5.71

22 382 1029 5.52 0.379 0.97

23 57.7 350 1029 5.33

24 422 1029 6.43 0.400

25 435 1030 5.79

26 57.6 445 1030 6.09 0.430 1.01

27 430 1030 6.17

29 454 1027 5.66 0.420 0.93

30 455 1023 5.56

Dec. 1 420 1028 5.31 0.450 0.92

2 465 1027 6.17

3 430 1027 5.34 0.350 0.82

4 365 1029 4.77

5 430 1030 5.83

6 515 1028 5.90 0.393 1.08

7 400 1028 5.57

8 390 1028 4.99 0.328 1.02

9 405 1030 5.17

10 57.6 370 1026 4.64 0.308 0.90

11 327 1030 4.65 0.325 1.11

12 390 1027 5.16 0.346 1.01

13 429 1029 5.66

14 360 1030 4.84

15 295 1029 4.32 0.291 0.82

16 445 1029 6.27

17 390 1032 5.59 0.358 0.73

18 420 1030 5.62

19 415 1027 5.03

20 57.5 390 1030 5.71 0.402 0.78

21 360 1023 4.25

22 360 1030 5.13 0.342 0.79

23 400 1031 5.08

24 435 1030 6.44

25 450 1029 5.13 0.329 0.77

26 465 5.55

27 470 5.53

28 535 8.18

29 535 7.67

30 656 9.68

31 57.6 490 1031 7.61 0.455 0.92

1904

Jan. 1 415 1030 6.41

2 490 1031 6.56

3 460 1030 5.91 0.319 0.79

4 58.1 430 1030 5.72

5 570 1028 6.36 0.402

6 445 1028 5.68

7 510 1028 5.91 0.367 0.99

8 420 1028 5.37

9 650 1027 7.29

10 635 1024 6.32 0.414 0.99

11 410 1028 4.87

12 450 1027 6.48

13 410 1027 5.34 0.435

14 532 1028 6.22 0.502

15 530 1028 5.98

16 515 1030 6.18

17 537 1030 6.73 0.429

18 57.8 395 1029 5.09

19 450 1030 5.72 0.427

20 420 1026 4.76

21 410 1029 5.26 0.401

22 485 1029 5.41

23 440 1031 5.07

24 485 1029 5.61 0.407

25 545 1027 6.18

26 485 1028 6.69 0.440

27 435 1028 5.64

28 490 1029 6.18 0.423

29 450 1029 5.68

30 475 5.59 0.376

31 490 6.61

Feb. 1 490 1030 6.47

2 57.5 400 1031 6.12 0.219

3 415 1030 5.85

4 545 1027 6.77 0.327

5 450 1030 5.64

6 485 1027 6.01

7 450 1026 5.62

8 57.4 415 1027 5.88

9 540 1026 6.67 0.449

10 410 1029 5.61

11 600 1025 6.70

12 430 1029 5.57 0.437

13 415 1028 5.50

14 480 1028 6.42 0.497

15 395 1030 4.95

16 500 1029 5.97 0.364

17 450 1030 5.62

18 57.3 430 1030 5.86 0.279

19 450 1029 6.21

20 455 1027 5.46

21 500 1027 6.16 0.424

22 445 1028 5.15

23 455 1027 5.63

24 420 1028 6.27

25 560 1027 6.28 0.403

26 630 1026 6.27

27 570 1026 6.87

28 515 1028 6.27 0.496

29 450 1030 5.43

Mar. 1 450 1027 6.02

2 445 1029 5.15

3 590 1028 6.30

4 415 1029 5.40

5 57.5 425 1027 5.48

6 548 1025 5.92 0.370

7 400 1029 4.68

8 530 1028 5.77

9 560 1028 5.84

10 560 1028 5.64

11 495 1028 5.79

12 515 1021 6.80

13 520 1029 6.43 0.370

14 600 1025 6.12

15 520 1026 5.87

16 57.5 525 1026 5.13

17 490 1026 4.97

18 450 1027 5.08

19 500 1024 5.85

20 500 1022 5.91 ⎫ 0.321 daily average 1.20 daily average

21 57.4 430 1025 5.52 ⎪

22 458 1033 5.94 ⎬

23 57.2 400 1029 5.61 ⎪

24 57.3 365 1029 4.31 ⎪

25 420 1029 5.39 ⎭

26 57.5 435 1027 5.85

27 595 1026 6.33

28 545 1027 6.00

29 435 1028 4.86

30 575 1026 6.26

31 495 1026 5.26

Apr. 1 570 1026 6.33

2 440 1030 6.07

3 487 1026 6.11 0.375

4 410 1028 5.78

5 390 1028 5.38

6 56.8 490 1028 5.56

7 56.5 530 1027 5.69

8 440 1029 5.41

9 465 1019 6.05

10 56.8 500 1029 6.00 0.382

11 500 1028 6.18

12 56.4 475 1029 5.55 0.366 0.870

Daily average for six months 466 1027 5.82 0.386 0.899

13 545 1029 6.77

14 440 1027 5.89

15 500 1028 5.91

16 485 1028 5.49

17 405 1029 5.99 0.393

18 465 1029 6.11

19 510 1030 7.68

20 430 1031 6.99

21 56.6 615 1029 8.67

22 320 1030 5.03

23 57.1 355 1032 5.72

24 455 1027 5.97

25 380 1027 4.93

26 450 1028 4.97 0.366

27 600 1025 6.62 0.553

28 56.9 385 1029 5.66 0.507

29 415 1029 5.28 0.488

30 56.9 462 1029 5.59 0.413

May 1 486 1027 5.54 0.409

2 405 1028 4.11 0.320

3 57.1 505 1027 5.48

4 456 1026 5.27

5 380 1026 4.88

6 530 1027 6.30

7 470 1024 5.44

8 57.6 460 1027 5.07

9 460 1026 4.28

10 57.4 493 1028 5.26

11 415 1029 4.61

12 530 1029 5.98

13 415 1031 4.72

14 57.2 405 1031 4.98 0.468

15 500 1029 5.31

16 505 1027 5.03

17 650 1020 5.69

18 550 1027 5.81

19 560 1027 6.05

20 615 1027 6.64

21 56.9 380 1032 5.20 0.421

22 475 1028 5.73

23 378 1028 4.60

24 383 1029 4.48

25 535 1025 5.14

26 56.9 355 1028 4.37

27 435 1026 4.93

28 57.5 555 1028 5.99 0.397

29 57.7 565 1027 6.27

30 700 1020 5.50

31 500 1025 5.13

June 1 630 1023 5.41

2 510 1020 4.16

3 530 1023 5.25

4 57.6 390 1029 5.25

5 400 1025 4.87

6 430 1027 5.16

7 480 1028 5.15

8 410 1027 4.95

9 420 1026 4.51

10 395 1026 4.27

11 57.5 510 1030 5.91

12 530 1027 5.95

13 57.6 485 1027 5.35

14 470 1030 5.16

15 560 1024 4.91

16 57.6 390 1029 5.26

17 408 1027 5.17

18 57.9 412 1030 5.07

19 458 1025 5.44

20 58.0 380 1026 4.49

21 480 1023 5.04

22 57.8 580 1025 6.16

23 57.9 535 1025 5.26 ⎫ 0.397 daily average 1.08 daily average

24 57.6 570 1024 5.30 ⎪

25 410 1027 4.43 ⎬

26 57.4 400 1027 4.66 ⎪

27 57.4 405 1027 4.98 ⎭

Daily average from Oct. 13, 1903 468 1027 5.69 0.392 0.904

Daily average from April 13 to June 27 5.40

June 28 57.5 595 1026 6.75

Scrutiny of the tables shows that during this period of nine months the body-weight was practically constant. The daily volume of urine was exceptionally small and fairly regular in amount, the average daily output for the nine months being 468 c.c. It is a noticeable fact that with a diminished intake of proteid food there is far less thirst, and consequently a greatly decreased demand for water or other fluids. Further, in view of the small nitrogenous waste there is no need on the part of the body for any large amount of fluid to flush out the kidneys. The writer has not had a turbid urine during the nine months’ period. With heavier eating of nitrogenous foods, an abundant water supply is a necessity to prevent the kidneys from becoming clogged, thereby explaining the frequent beneficial results of the copious libations of mineral waters, spring waters, etc., frequently called for after, or with, heavy eating. Obviously, a small volume of urine each day means so much less wear and tear of the delicate mechanism of the kidneys. Somewhat noticeable, in a general way, is the apparent relationship between the volume of the urine and the nitrogen output, in harmony with the well-known diuretic action of urea. The specific gravity of the urine shows variation only within narrow limits, the daily average for the nine months being 1027.

Uric acid is noticeably small in quantity, the average daily output for the nine months’ period, based upon the determinations made, being only 0.392 gram.

Chief interest, however, centres around the figures for total nitrogen, since these figures give for each day the extent of the proteid metabolism; i. e., the amount of proteid material broken down in the body each day in connection with the wear and tear of the bodily machinery. To fully grasp the significance of these data, it should be remembered that the prevalent dietary standards are based upon the assumption that the average adult must metabolize each day at least 16 grams of nitrogen. Indeed, that is what actual analysis of the urine indicates in most cases. If now we look carefully through the figures shown in the above tables, covering a period from October 13, 1903, to June 28, 1904, it is seen that the daily nitrogen excretion is far different from 16 grams. Indeed, the figures for nitrogen are exceedingly low, and, moreover, they vary little from day to day. The average daily output of nitrogen through the urine for the entire period of nearly nine months is only 5.699 grams.

For the first six months the average daily excretion amounted to 5.82 grams of nitrogen, while from April 12 to June 28 the average daily excretion of nitrogen was 5.40 grams, thus showing a slight tendency downward. On the whole, however, there is shown a somewhat remarkable uniformity in the daily excretion. Thus, the average daily excretion for the month of November was 5.79 grams of nitrogen, for the month of March 5.66 grams, thus showing very little difference in the output of nitrogen through the kidneys in these two periods, three months apart. In other words, the extent of proteid katabolism was essentially the same throughout the entire nine months, implying that the amount of proteid food eaten must have been fairly constant, and that the body had adapted itself to this new level of nutrition from which there was no tendency to deviate. There was no weighing out of food and no attempt to follow any specified diet. The greatest possible variety of simple foods was indulged in, and the dictates of the appetite were followed with the single precaution that excess was avoided. In other words, it was temperance in diet, and not prohibition. Yet it is equally true, in the writer’s case at least, that the appetite itself unconsciously served as a regulator, since there was, as a rule, no necessity to hold the appetite in check to avoid excess. Doubtless, the writer’s knowledge of the general composition of food-stuffs has had some influence in the choice of foods, and thereby aided in bringing about this somewhat remarkable uniformity in the daily output of nitrogen for such a long period of time on an unrestricted diet.

What now do the nitrogen figures show regarding the amount of proteid material metabolized each day? It will be remembered that the Voit standard calls for 118 grams of proteid or albuminous food daily, of which 105 grams should be absorbable, in order to maintain the body in a condition of nitrogen equilibrium, and in a state of physical vigor and general tone. This would mean a daily excretion through the urine of at least 16 grams of nitrogen. The daily output of nitrogen in the case under discussion, however, was 5.699 grams for a period of nearly nine months. This amount of nitrogen excreted through the urine means only 35.6 grams of proteid metabolized, or about one-third the amount called for by the Voit standard, or the standards generally adopted as expressing man’s daily requirement of proteid food. But was the body in nitrogenous equilibrium on this small amount of proteid food? Naturally, this question might be answered in the affirmative, on the basis of the constancy in body-weight for the period from October to June, but more decisive proof is needed. The question was therefore settled by a careful comparison of the income and output, in which all the food eaten was carefully weighed and analyzed, while the nitrogen of the urine and fæces was determined with equal accuracy. The first experiment of this character to be quoted is for the week commencing March 20, a period of six days.

Following are the diets made use of each day, the weights of the various food-stuffs being given in grams. Likewise is shown the nitrogen content of the several food-stuffs for each day, and also a comparison of the nitrogen intake with the output of nitrogen through the urine:

Sunday, March 20, 1904.

Breakfast, 7.45 A. M.—One cup coffee, i. e., coffee 137.5 grams, cream 30.5 grams, sugar 9 grams.

Dinner, 1.30 P. M.—Stewed chicken 50 grams, mashed potato 131 grams, biscuit 49 grams, butter 13 grams, chocolate pudding 106 grams, one small cup coffee, i. e., coffee 64 grams, sugar 12 grams, cheese crackers 29 grams.

Supper, 6.30 P. M.—Lettuce sandwiches 56 grams, biscuit 35 grams, butter 6 grams, one cup tea, i. e., tea 170 grams, sugar 7 grams, sponge cake 47 grams, sliced oranges 82 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 64 + 137 = 201.5 × 0.042 = 0.085 gram.

Cream 30.5 × 0.41 = 0.125

Sugar 12 + 9 + 7 = 28.0 × 0.00 = 0.000

Chicken 50.0 × 4.70 = 2.350

Mashed potato 131.0 × 0.30 = 0.393

Biscuit 35 + 49 = 84.0 × 1.49 = 1.251

Butter 13 + 6 = 19.0 × 0.10 = 0.019

Chocolate pudding 106.0 × 0.86 = 0.911

Cheese crackers 29.0 × 2.54 = 0.737

Lettuce sandwich 56.0 × 0.92 = 0.515

Tea 170.0 × 0.048 = 0.082

Sponge cake 47.0 × 0.98 = 0.461

Sliced orange 82.0 × 0.073 = 0.060

Total nitrogen in food 6.989 grams.

Total nitrogen in urine 5.910

Fuel value of the food 1708 calories.[32]

Monday, March 21, 1904.

Breakfast, 7.45 A. M.—Coffee 119 grams, cream 30 grams, sugar 9 grams.

Lunch, 1.30 P. M.—One shredded wheat biscuit 31 grams, cream 116 grams, wheat gems 33 grams, butter 7 grams, tea 185 grams, sugar 10 grams, cream cake 53 grams.

Dinner, 6.30 P. M.—Pea soup 114 grams, lamb chop 24 grams, boiled sweet potato 47 grams, wheat gems 76 grams, butter 13 grams, cream cake 52 grams, coffee 61 grams, sugar 10 grams, cheese crackers 16 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 119 + 61 = 180 × 0.042 = 0.076 gram.

Cream 30 + 116 = 146 × 0.41 = 0.600

Sugar 9 + 10 + 10 = 29 × 0.00 = 0.000

Shredded wheat biscuit 31 × 1.62 = 0.502

Tea 185 × 0.048 = 0.089

Wheat gems 33 + 76 = 109 × 1.46 = 1.591

Butter 7 + 13 = 20 × 0.10 = 0.020

Cream cake 53 + 52 = 105 × 0.97 = 1.018

Pea soup 114 × 1.00 = 1.140

Lamb chop 24 × 4.54 = 1.090

Sweet potato 47 × 0.18 = 0.085

Cheese crackers 16 × 2.54 = 0.410

Total nitrogen in food 6.621 grams.

Total nitrogen in urine 5.520

Fuel value of the food 1713 calories.

Tuesday, March 22, 1904.

Breakfast, 7.45 A. M.—Coffee 97 grams, cream 26 grams, sugar 9 grams.

Lunch, 1.30 P. M.—Baked potato 83 grams, fried sausage 36 grams, soda biscuit 39 grams, butter 12 grams, tea 137 grams, sugar 10 grams, cream meringue 59 grams.

Dinner, 6.30 P. M.—Chicken broth 146 grams, bread 52 grams, butter 15 grams, creamed potato 76 grams, custard 76 grams, coffee 50 grams, sugar 11 grams, cheese crackers 10 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 97 + 50 = 147 × 0.042 = 0.060 gram.

Cream 26 × 0.42 = 0.109

Sugar 9 + 10 + 11 = 30 × 0.00 = 0.000

Baked potato 83 × 0.40 = 0.332

Fried sausage 36 × 3.06 = 1.101

Soda biscuit 39 × 1.66 = 0.647

Butter 12 + 15 = 27 × 0.10 = 0.027

Tea 137 × 0.048 = 0.066

Cream meringue 59 × 0.92 = 0.543

Chicken broth 146 × 0.78 = 1.138

Bread 52 × 1.66 = 0.863

Creamed potato 76 × 0.42 = 0.319

Custard 76 × 0.82 = 0.623

Cheese crackers 10 × 2.54 = 0.254

Total nitrogen in food 6.082 grams.

Total nitrogen in urine 5.940

Fuel value of the food 1398 calories.

Wednesday, March 23, 1904.

Breakfast, 7.45 A. M.—Coffee 103 grams, cream 30 grams, sugar 10 grams.

Lunch, 1.30 P. M.—Creamed codfish 64 grams, potato balls 54 grams, biscuit 44 grams, butter 22 grams, tea 120 grams, sugar 10 grams, wheat griddle cakes 133 grams, maple syrup 108 grams.

Dinner, 6.30 P. M.—Creamed potato 85 grams, biscuit 53 grams, butter 15 grams, apple-celery-lettuce salad 50 grams, apple pie 127 grams, coffee 67 grams, sugar 8 grams, cheese crackers 17 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 103 + 67 = 170 × 0.042 = 0.071 gram.

Sugar 10 + 10 + 8 = 28 × 0.00 = 0.000

Cream 30 × 0.43 = 0.129

Potato balls 54 × 0.68 = 0.367

Creamed codfish 64 × 1.26 = 0.806

Biscuit 44 + 53 = 97 × 1.66 = 1.610

Butter 22 + 15 = 37 × 0.10 = 0.037

Tea 120 × 0.048 = 0.058

Wheat griddle cakes 133 × 1.32 = 1.760

Maple syrup 108 × 0.019 = 0.021

Creamed potato 85 × 0.53 = 0.450

Cheese crackers 17 × 2.54 = 0.431

Apple-celery salad 50 × 0.20 = 0.100

Apple pie 127 × 0.75 = 0.953

Total nitrogen in food 6.793 grams.

Total nitrogen in urine 5.610

Fuel value of the food 1984 calories.

Thursday, March 24, 1904.

Breakfast, 7.45 A. M.—Coffee 100 grams, cream 25 grams, sugar 8 grams.

Lunch, 1.30 P. M.—Shredded wheat biscuit 29 grams, cream 118 grams, wheat gems 60 grams, butter 8 grams, tea 100 grams, sugar 7 grams, apple pie 102 grams.

Dinner, 6.30 P. M.—Milk-celery soup 140 grams, bread 15 grams, butter 1 gram, lettuce sandwiches 62 grams, tea 100 grams, sugar 10 grams, lemon pie 109 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 100 × 0.042 = 0.042 gram.

Cream 25 + 118 = 143 × 0.43 = 0.615

Sugar 8 + 7 + 10 = 25 × 0.00 = 0.000

Shredded wheat biscuit 29 × 1.76 = 0.510

Wheat gems 60 × 1.17 = 0.702

Butter 8 + 1 = 9 × 0.10 = 0.009

Tea 100 + 100 = 200 × 0.048 = 0.096

Apple pie 102 × 0.75 = 0.765

Milk-celery soup 140 × 0.42 = 0.588

Bread 15 × 1.36 = 0.204

Lettuce sandwich 62 × 1.02 = 0.632

Lemon pie 109 × 0.82 = 0.894

Total nitrogen in food 5.057 grams.

Total nitrogen in urine 4.310

Fuel value of the food 1594 calories.

Friday, March 25, 1904.

Breakfast, 7.45 A. M.—Coffee 100 grams, cream 25 grams, sugar 9 grams.

Lunch, 1.30 P. M.—Halibut with egg sauce 108 grams, mashed potato 89 grams, biscuit 48 grams, butter 10 grams, chocolate-cream cake 90 grams, tea 100 grams, sugar 9 grams.

Dinner, 6.30 P. M.—Milk-celery soup 121 grams, lettuce sandwiches 61 grams, creamed potato 65 grams, lettuce-apple-celery salad 74 grams, coffee 70 grams, sugar 10 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 100 + 70 = 170 × 0.042 = 0.071 gram.

Cream 25 × 0.40 = 0.100

Sugar 9 + 9 + 10 = 28 × 0.00 = 0.000

Halibut, etc. 108 × 3.02 = 3.262

Mashed potato 89 × 0.26 = 0.231

Biscuit 48 × 1.52 = 0.730

Butter 10 × 0.10 = 0.010

Tea 100 × 0.048 = 0.048

Chocolate-cream cake 90 × 0.99 = 0.891

Celery-milk soup 121 × 0.52 = 0.629

Lettuce sandwich 61 × 0.98 = 0.598

Lettuce-apple salad 74 × 0.21 = 0.155

Creamed potato 65 × 0.37 = 0.241

Total nitrogen in food 6.966 grams.

Total nitrogen in urine 5.390

Fuel value of the food 1285 calories.

NITROGEN BALANCE.—Chittenden.

Nitrogen Taken in. Output.

Nitrogen in Urine. Weight of Fæces[33] (dry).

March 20 6.989 grams. 5.91 grams. 3.6 grams.

21 6.621 5.52 0.0

22 6.082 5.94 12.0

23 6.793 5.61 18.5

24 5.057 4.31 23.0

25 6.966 5.39 16.9

74.0 grams contain 6.42% N.

38.508 32.68 + 4.75 grams nitrogen.

38.508 grams nitrogen. 37.43 grams nitrogen.

Nitrogen balance for six days = +1.078 grams.

Nitrogen balance per day = +0.179 gram.

Average Intake.

Calories per day 1613.

Nitrogen per day 6.40 grams.

Examination of the results shown in the foregoing balance makes it quite clear that the body was essentially in nitrogenous equilibrium. Indeed, there was a slight plus balance, showing that even with the small intake of proteid food the body was storing up nitrogen at the rate of 0.16 gram per day. The average daily intake of nitrogen for the six days’ period was 6.40 grams, equal to 40.0 grams of proteid or albuminous food. The average daily output of nitrogen through the urine and fæces was 6.24 grams. The average daily output of nitrogen through the urine for the six days’ period was 5.44 grams, corresponding to the metabolism of 34 grams of proteid material. When these figures are contrasted with the usually accepted standards of proteid requirement for the healthy man, they are certainly somewhat impressive, especially when it is remembered that the body at that date had been in essentially this same condition for at least six months, and probably for an entire year. The Voit standard of 118 grams of proteid, with an equivalent of at least 18 grams of nitrogen and calling for the metabolism of 105 grams of proteid, or 16.5 grams of nitrogen per day, makes clear how great a physiological economy had been accomplished. In other words, the consumption of proteid food was reduced to at least one-third the daily amount generally considered as representing the average requirement of the healthy man, and this with maintenance of body-weight at practically a constant point for the preceding ten months, and, so far as the writer can observe, with no loss of vigor, capacity for mental and physical work, or endurance. Indeed, the writer is disposed to maintain that he has done more work and led a more active life in every way during the period of this experiment, and with greater comfort and less fatigue than usual. His health has certainly been of the best during this period.

In this connection it may be well to call attention to the completeness of the utilization of the daily food in this six days’ experiment, as shown by the small amount of refuse discharged per rectum, indicating as it does the high efficiency of the digestive processes and of the processes of absorption. The refuse matter for the entire period of six days amounted when dry to only 74 grams, and when it is remembered how large a proportion of this refuse must of necessity be composed of the cast-off secretions from the body, it will be seen how thorough must have been the utilization of the food by the system. The loss of nitrogen to the body per day through the fæces amounted to only 0.79 gram, and this on a mixed diet containing considerable matter not especially concentrated, and on some days with noticeable amounts of food, such as salads, not particularly digestible.

Finally, emphasis should be laid upon the fact that this economy of proteid food, this establishment of nitrogen equilibrium on a low proteid intake, was accomplished without increase in the daily intake of non-nitrogenous foods. In fact, the amount of fats and carbohydrates was likewise greatly reduced, far below the minimal standard of 3000 calories as representing the potential energy or fuel value of the daily diet. Indeed, during the balance period of six days just described the average fuel value of the food per day was only a little over 1600 calories.

As the experiment continued and the record for the months of April and May was obtained, it became evident from the nitrogen results that the rate of proteid katabolism was being still more reduced. A second balance experiment was therefore tried with a view to seeing if the body was still in nitrogen equilibrium, and also to ascertain whether the fuel value of the food still showed the same low calorific power. For a period of five days, June 23 to 27, the intake of food and the entire output were carefully compared, with the results shown in the accompanying tables.

Thursday, June 23, 1904.

Breakfast.—Coffee 123 grams, cream 50 grams, sugar 11 grams.

Lunch.—Omelette 50 grams, French fried potatoes 70 grams, bacon 10 grams, wheat gems 43 grams, butter 9 grams, strawberries 125 grams, sugar 20 grams, cream cake 59 grams.

Dinner.—Beefsteak 34 grams, peas 60 grams, creamed potato 97 grams, bread 26 grams, butter 17 grams, lettuce-orange salad 153 grams, crackers 43 grams, cream cheese 15 grams, coffee 53 grams, sugar 12 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 123 + 53 = 176 × 0.045 = 0.079 gram.

Cream 50 × 0.35 = 0.175

Sugar 11 + 20 + 12 = 43 × 0.00 = 0.000

Omelette 50 × 1.32 = 0.660

French fried potatoes 70 × 0.37 = 0.259

Bacon 10 × 3.43 = 0.343

Wheat gems 43 × 1.49 = 0.641

Butter 9 + 17 = 26 × 0.13 = 0.034

Strawberries 125 × 0.11 = 0.138

Cream cake 59 × 0.98 = 0.578

Beefsteak 34 × 4.14 = 1.408

Peas 60 × 0.97 = 0.582

Creamed potato 97 × 0.34 = 0.330

Bread 26 × 1.23 = 0.320

Lettuce-orange salad 153 × 0.15 = 0.230

Crackers 43 × 1.40 = 0.602

Cream cheese 15 × 1.62 = 0.243

Total nitrogen in food 6.622 grams.

Total nitrogen in urine 5.260

Fuel value of the food 1863 calories.

Friday, June 24, 1904.

Breakfast.—Coffee 96 grams, sugar 8 grams, milk 32 grams.

Lunch.—Creamed codfish 89 grams, baked potato 95 grams, butter 10 grams, hominy gems 58 grams, strawberries 86 grams, sugar 26 grams, ginger snaps 47 grams.

Dinner.—Cold tongue 14 grams, fried potato 48 grams, peas 60 grams, wheat gems 30 grams, butter 11 grams, lettuce-orange salad with mayonnaise dressing 155 grams, crackers 22 grams, cream cheese 14 grams, ginger snaps 22 grams, coffee 58 grams, sugar 10 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 123 + 53 = 176 × 0.045 = 0.079 gram.

Sugar 8 + 26 + 10 = 44 × 0.00 = 0.000

Milk 32 × 0.51 = 0.163

Creamed codfish 89 × 1.78 = 1.584

Baked potato 95 × 0.29 = 0.276

Butter 10 + 11 = 21 × 0.13 = 0.027

Hominy gems 58 × 1.20 = 0.696

Strawberries 86 × 0.11 = 0.095

Ginger snaps 47 + 22 = 69 × 1.15 = 0.794

Cold tongue 14 × 4.87 = 0.682

Fried potato 48 × 0.37 = 0.178

Peas 60 × 0.94 = 0.564

Wheat gems 30 × 1.45 = 0.435

Lettuce-orange salad, etc. 155 × 0.15 = 0.233

Crackers 22 × 1.40 = 0.308

Cream cheese 14 × 1.62 = 0.227

Total nitrogen in food 6.331 grams.

Total nitrogen in urine 5.300

Fuel value of the food 1506 calories.

Saturday, June 25, 1904.

Breakfast.—Coffee 101 grams, milk 36 grams, sugar 13 grams.

Lunch.—Omelette 50 grams, bacon 9 grams, French fried potato 23 grams, biscuit 29 grams, butter 8 grams, cream cheese 17 grams, iced tea 150 grams, sugar 15 grams, ginger snaps 42 grams.

Dinner.—Wheat popovers 57 grams, butter 10 grams, lettuce-orange salad with mayonnaise dressing 147 grams, cream cheese 21 grams, crackers 22 grams, cottage pudding 82 grams, coffee 48 grams, sugar 11 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 1201 + 48 = 149 × 0.045 = 0.067 gram.

Milk 36 × 0.46 = 0.166

Sugar 13 + 15 + 11 = 39 × 0.00 = 0.000

Omelette 50 × 1.42 = 0.710

Bacon 9 × 2.66 = 0.239

French fried potato 23 × 0.57 = 0.131

Biscuit 29 × 1.35 = 0.392

Butter 8 + 10 = 18 × 0.13 = 0.023

Iced tea 150 × 0.018 = 0.027

Ginger snaps 42 × 1.15 = 0.483

Cream cheese 17 + 21 = 38 × 1.62 = 0.616

Wheat popovers 57 × 1.64 = 0.935

Lettuce-orange salad 147 × 0.15 = 0.221

Crackers 22 × 1.40 = 0.308

Cottage pudding 82 × 0.76 = 0.623

Total nitrogen in food 4.941 grams.

Total nitrogen in urine 4.430

Fuel value of the food 1392 calories.

Sunday, June 26, 1904.

Breakfast.—Coffee 122 grams, cream 31 grams, sugar 8 grams.

Dinner.—Roast lamb 50 grams, baked potato 52 grams, peas 64 grams, biscuit 32 grams, butter 12 grams, lettuce salad 43 grams, cream cheese 21 grams, toasted crackers 23 grams, blanc mange 164 grams.

Supper.—Iced tea 225 grams, sugar 29 grams, lettuce sandwich 51 grams, strawberries 130 grams, sugar 22 grams, cream 40 grams, sponge cake 31 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 122 × 0.045 = 0.055 gram.

Cream 31 + 40 = 71 × 0.32 = 0.227

Sugar 8 + 26 + 10 = 44 × 0.00 = 0.000

Roast lamb 50 × 4.28 = 2.140

Baked potato 52 × 0.29 = 0.151

Peas 64 × 1.04 = 0.666

Biscuit 32 × 1.35 = 0.432

Butter 12 × 0.13 = 0.016

Lettuce salad 43 × 0.23 = 0.099

Cream cheese 21 × 1.62 = 0.340

Toasted crackers 23 × 1.36 = 0.313

Blanc mange 164 × 0.35 = 0.574

Iced tea 225 × 0.018 = 0.041

Lettuce sandwich 51 × 0.85 = 0.434

Strawberries 130 × 0.11 = 0.143

Sponge cake 31 × 0.94 = 0.291

Total nitrogen in food 5.922 grams.

Total nitrogen in urine 4.660

Fuel value of the food 1533 calories.

Monday, June 27, 1904.

Breakfast.—Coffee 112 grams, cream 22 grams, sugar 10 grams.

Lunch.—Roast lamb 9 grams, baked potato 90 grams, wheat gems 47 grams, butter 12 grams, sugar 25 grams, iced tea 250 grams, vanilla éclair 47 grams.

Dinner.—Lamb chop 32 grams, asparagus 49 grams, butter 17 grams, creamed potato 107 grams, bread 35 grams, lettuce-orange salad with mayonnaise dressing 150 grams, cream cheese 12 grams, crackers 21 grams, coffee 63 grams, sugar 9 grams.

Food. Grams. Per cent Nitrogen. Total Nitrogen.

Coffee 123 + 53 = 176 × 0.045 = 0.079 gram.

Cream 22 × 0.32 = 0.070

Sugar 10 + 25 + 9 = 44 × 0.00 = 0.000

Iced tea 250 × 0.018 = 0.045

Baked potato 90 × 0.25 = 0.225

Wheat gems 47 × 1.65 = 0.776

Butter 12 + 17 = 29 × 0.13 = 0.038

Roast lamb 9 × 4.28 = 0.385

Vanilla éclair 47 × 0.85 = 0.400

Lamb chops 32 × 4.57 = 1.462

Asparagus 49 × 0.59 = 0.289

Creamed potato 107 × 0.40 = 0.428

Bread 35 × 1.33 = 0.466

Lettuce-orange salad, etc. 150 × 0.23 = 0.345

Cream cheese 12 × 1.62 = 0.194

Crackers 21 × 1.35 = 0.284

Total nitrogen in food 5.486 grams.

Total nitrogen in urine 4.980

Fuel value of the food 1454 calories.

NITROGEN BALANCE.—Chittenden.

Nitrogen Taken in. Output.

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.

Date. Body-weight. Urine.

Volume. 24 hours. Sp. Gr. Nitrogen. Uric Acid. P₂O₅.

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 ⎫ 7.00 daily average 0.410 daily average 1.72 daily average

24 74.0 1200 1017 ⎪

25 1030 ⎪

26 74.0 850 ⎬

27 935 1020 ⎪

28 74.5 870 1021 ⎪

29 74.5 993 1017 ⎭

30 74.5 650 1023 ⎫ 7.28 0.480 1.80

Dec. 1 74.5 960 1018 ⎪

2 790 1023 ⎪

3 74.0 880 1023 ⎬

4 1200 1016 ⎪

5 74.0 930 1021 ⎪

6 1080 1019 ⎭

7 73.5 790 1023 ⎫ 7.63 0.438 1.91

8 73.5 965 1025 ⎪

9 74.0 1130 1017 ⎪

10 73.0 630 1031 ⎬

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 ⎫ 0.259 1.10

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 ⎬

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 ⎫ 7.64 0.438 1.16

28 830 1026 ⎪

29 730 1027 ⎪

30 670 1033 ⎪

31 630 ⎬

1904 ⎪

Jan. 1 550 ⎪

2 1030 1022 ⎪

3 1020 1019 ⎭

4 750 1021 5.63 ⎫ 0.436 1.41

5 1030 1016 5.31 ⎪

6 73.0 815 1023 5.77 ⎪

7 72.7 930 1019 6.02 ⎬

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 ⎫ 0.443 1.43

12 72.2 1230 1015 6.71 ⎪

13 71.8 1250 1016 7.43 ⎪

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 ⎫ 0.465 1.48

19 825 1023 6.58 ⎪

20 1035 1021 6.70 ⎪

21 725 1030 6.96 ⎬

22 815 1023 6.99 ⎪

23 950 1018 6.27 ⎪

24 71.6 790 1025 5.93 ⎭

25 71.3 740 1027 5.33 ⎫ 0.429 1.29

26 600 1030 5.44 ⎪

27 965 1020 6.89 ⎪

28 1045 1015 6.33 ⎬

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 ⎫ 0.451 1.40

2 950 1023 6.84 ⎪

3 1210 1019 8.10 ⎪

4 71.5 985 1020 6.74 ⎬

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 ⎫ 0.420

16 995 1019 6.86 ⎪

17 1055 1018 5.63 ⎪

18 1185 1015 6.11 ⎬

19 712 1025 5.72 ⎪

20 70.5 1000 1021 7.38 ⎪

21 70.6 1235 1014 5.93 ⎭

22 900 1018 6.16 ⎫ 0.488

23 70.2 840 1020 5.49 ⎪

24 875 1017 5.83 ⎪

25 70.5 1450 1018 8.09 ⎬

26 70.2 1485 1015 6.68 ⎪

27 1300 1013 5.93 ⎪

28 69.2 735 1022 5.91 ⎭

29 575 1030 6.21 ⎫ 0.462

Mar. 1 975 1019 7.51 ⎪

2 70.5 1240 1015 7.29 ⎪

3 1400 1013 6.63 ⎬

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 ⎫ 0.413

8 70.9 1220 1015 5.56 ⎪

9 70.9 1285 1015 5.70 ⎪

10 1000 1020 6.24 ⎬

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 ⎫ 0.485

15 70.6 1240 1017 7.29 ⎪

16 70.8 1450 1016 7.47 ⎪

17 70.2 780 1022 6.41 ⎬

18 1230 1012 6.57 ⎪

19 70.1 780 1027 6.41 ⎪

20 950 1020 6.21 ⎭

21 70.7 1005 1020 6.36 ⎫ 0.527

22 70.9 1525 1014 6.50 ⎪

23 70.6 825 1023 6.39 ⎪

24 70.4 550 1029 6.07 ⎬

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 ⎫ 0.389

29 70.5 1370 1014 6.58 ⎪

30 70.3 1185 1016 6.26 ⎪

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 ⎫ 0.356 1.54

5 1110 1020 6.39 ⎪

6 1055 1022 7.53 ⎪

7 575 1027 6.42 ⎬

8 650 1031 6.94 ⎪

9 795 1026 7.06 ⎪

10 1230 1020 7.01 ⎭

11 850 1021 5.61 ⎫ 0.419

12 1005 1018 6.66 ⎪

13 695 1020 5.75 ⎪

14 69.6 910 1027 5.79 ⎬

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 ⎫ 0.453

19 70.7 1230 1016 5.90 ⎪

20 70.5 1485 1014 5.70 ⎪

21 70.1 1125 1023 7.09 ⎬

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 ⎫ 0.373

26 69.9 1000 1021 6.18 ⎪

27 70.1 1295 1015 6.06 ⎪

28 70.0 1425 1013 5.56 ⎬

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 ⎫ 0.260

3 69.8 700 1022 5.46 ⎪

4 69.5 900 1019 6.48 ⎪

5 69.6 750 1023 6.52 ⎬

6 69.7 1120 1019 7.26 ⎪

7 1010 1020 6.00 ⎪

8 1165 1015 6.01 ⎭

9 69.7 880 1020 5.38 ⎫ 0.408

10 70.0 935 1019 5.22 ⎪

11 69.6 1050 1017 6.05 ⎪

12 69.8 950 1020 6.15 ⎬

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 ⎫ 0.325

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 ⎪

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 ⎫ 0.476

29 1370 1016 7.83 ⎬

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 Taken in. Output.

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 Taken in. Output.

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.

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.

UNDERHILL.

Date. Body-weight. Urine.

Volume. 24 hours. Sp. Gr. Nitrogen. Uric Acid. P₂O₅.

1903 kilos c.c. grams gram grams

Oct. 11 65.4 1300 1015 10.37 0.611 1.72

12 700 1022 9.07

13 1050 1022 12.35 0.820 2.15

14 1400 1017 12.01

15 870 1020 11.48 0.671 1.76

16 1165 1013 12.09

17 840 1020 11.24

18 1150 1017 10.00 0.613 1.77

19 678 1022 7.79

20 1165 1018 10.76 0.603 1.60

21 1460 1017 11.91

22 950 1019 10.71 0.643 1.73

23 1165 1017 12.82

24 65.4 850 1025 12.49

25 850 1022 11.07 0.645 1.76

26 1025 1018 ⎫ 8.31 daily average 0.465 daily average 1.18 daily average

27 775 1018 ⎪

28 1140 1015 ⎬

29 765 1020 ⎪

30 860 1019 ⎪

31 1150 1015 ⎭

Nov. 1 750 1020 ⎫ 7.91 0.469 1.30

2 675 1022 ⎪

3 955 1014 ⎪

4 1270 1012 ⎬

5 885 1015 ⎪

6 770 1020 ⎪

7 860 1021 ⎭

8 775 1020 ⎫ 7.86 0.537 1.40

9 890 1018 ⎪

10 1070 1018 ⎪

11 755 1020 ⎬

12 950 1023 ⎪

13 1100 1017 ⎪

14 980 1015 ⎪

15 630 1020 ⎭

16 65.0 700 1020 ⎫ 7.82 0.467 1.49

17 1000 1015 ⎪

18 940 1018 ⎪

19 770 1023 ⎬

20 770 1025 ⎪

21 790 1020 ⎪

22 770 1021 ⎭

23 590 1025 ⎫ 8.55 0.476 1.67

27 710 1024 ⎬

28 1080 1017 ⎪

29 760 1019 ⎭

30 870 1018 ⎫ 7.72 0.506 1.43

Dec. 1 860 1017 ⎪

2 1120 1015 ⎪

3 1450 1009 ⎬

4 720 1019 ⎪

5 720 1019 ⎪

6 510 1027 ⎭

7 65.1 700 1018 ⎫ 7.36 0.474 1.44

8 650 1018 ⎪

9 860 1013 ⎪

10 975 1020 ⎬

11 800 1021 ⎪

12 830 1018 ⎪

13 750 1019 ⎭

14 860 1018 ⎫ 8.11 0.497 1.35

15 870 1019 ⎪

16 880 1015 ⎪

17 820 ⎬

18 760 1021 ⎪

19 860 1017 ⎪

20 520 1023 ⎭

21 1200 1014 ⎫ 7.18 1.05

22 65.0 510 1025 ⎭

23 650 ⎫ 6.70 0.356 0.97

24 670 ⎪

25 500 ⎬

26 550 ⎪

27 850 ⎭

28 65.2 930 ⎫ 8.70 0.626 1.21

29 1200 ⎪

30 750 ⎪

31 1280 ⎬

Jan. 1 750 ⎪

2 750 ⎪

3 870 ⎪

4 1230 ⎭

5 720 1023 ⎫ 8.23 0.530 1.24

6 960 1020 ⎪

7 760 1022 ⎬

8 1000 1017 ⎪

9 720 1025 ⎪

10 65.1 730 1021 ⎭

11 700 1016 ⎫ 7.74 0.618 1.20

12 650 1020 ⎪

13 700 1024 ⎪

14 660 1025 ⎬

15 610 1025 ⎪

16 710 1024 ⎪

17 660 1022 ⎭

18 770 1016 ⎫ 7.80 0.705 1.14

19 64.8 700 1022 ⎪

20 1130 1018 ⎪

21 830 1020 ⎬

22 600 1019 ⎪

23 480 1021 ⎪

24 750 1019 ⎭

25 680 1020 ⎫ 6.85 0.500 1.07

26 800 1018 ⎪

27 800 1020 ⎪

28 700 1020 ⎬

29 64.4 1010 1014 ⎪

30 980 1018 ⎪

31 820 1015 ⎭

Feb. 1 990 1015 ⎫ 7.98 0.535 1.24

2 660 1020 ⎪

3 64.4 1060 1015 ⎪

4 980 1017 ⎬

5 970 1014 ⎪

6 790 1019 ⎪

7 1120 1015 ⎭

8 715 1021 8.11

9 64.4 1225 1014 7.49 0.450

10 64.4 770 1018 6.14 0.505

11 64.5 715 1022 8.02 0.568

12 850 1021 8.82 0.539

13 490 1028 7.17 0.505

14 64.4 795 1020 7.73 0.543

15 780 1021 ⎫ 8.27 0.558

16 920 1023 ⎪

17 660 1021 ⎪

18 640 1027 ⎬

19 730 1023 ⎪

20 840 1027 ⎪

21 700 1018 ⎭

22 440 1025 ⎫ 7.47 0.556

23 600 1023 ⎪

24 750 1022 ⎪

25 830 1017 ⎬

26 64.0 870 1021 ⎪

27 910 1015 ⎪

28 950 1014 ⎭

29 600 1021 ⎫ 7.15 0.526

Mar. 1 680 1021 ⎪

2 1120 1011 ⎪

3 640 1021 ⎬

4 1080 1016 ⎪

5 1220 1034 ⎪

6 890 1015 ⎭

7 1000 1014 ⎫ 8.18 0.682

8 650 1020 ⎪

9 750 1020 ⎪

10 850 1018 ⎬

11 950 1014 ⎪

12 1000 1016 ⎪

13 64.2 860 1019 ⎭

14 840 1020 ⎫ 7.83 0.540

15 920 1016 ⎪

16 750 1020 ⎪

17 820 1017 ⎬

18 1220 1012 ⎪

19 920 1015 ⎪

20 700 1022 ⎭

21 900 1015 ⎫ 8.04 0.733

22 980 1013 ⎪

23 990 1014 ⎪

24 750 1020 ⎬

25 820 1017 ⎪

26 700 1021 ⎪

27 910 1020 ⎭

28 930 1017

30 900 1020

31 450 ⎫ 7.87 0.530 1.44

Apr. 1 500 ⎪

2 420 ⎪

3 600 ⎪

4 950 ⎪

5 930 ⎬

6 980 ⎪

7 600 ⎪

8 980 ⎪

9 800 ⎪

10 810 ⎭

11 65.2 940 1017 ⎫ 9.46 ⎫ 0.496

12 710 1024 ⎬ ⎪

13 750 1024 ⎭ ⎪

14 740 1020 7.55 ⎬

15 590 1024 6.51 ⎪

16 900 1016 7.51 ⎪

17 1290 1009 5.11 ⎭

18 65.2 590 1017 5.96 ⎫ 0.527

19 630 1024 6.39 ⎪

20 670 1022 7.48 ⎪

21 900 1021 8.10 ⎬

22 980 1017 7.00 ⎪

23 850 1019 7.60 ⎪

24 640 1023 7.33 ⎭

25 65.0 600 1021 8.23 ⎫ 0.490

26 610 1014 5.82 ⎪

27 600 1023 7.27 ⎪

28 970 1015 7.05 ⎬

29 795 1017 5.91 ⎪

30 700 1021 6.80 ⎪

May 1 795 1016 5.72 ⎭

2 65.2 860 1017 6.50 ⎫ 0.344

3 1120 1016 6.92 ⎪

4 1090 1015 6.54 ⎪

5 580 1021 5.92 ⎬

6 700 1020 7.29 ⎪

7 895 1017 8.97 ⎪

8 800 1016 7.30 ⎭

9 65.2 895 1019 6.28 ⎫ 0.416

10 850 1019 6.27 ⎪

11 960 1019 7.26 ⎪

12 690 1022 6.29 ⎬

13 990 1017 7.96 ⎪

14 690 1022 7.21 ⎪

15 900 1015 6.15 ⎭

16 65.1 945 1014 5.10 ⎫ 0.364

17 1090 1016 6.15 ⎪

18 620 1020 5.21 ⎪

19 1110 1015 6.53 ⎪

20 895 1016 6.12 ⎬

21 810 1019 6.95 ⎪

22 1110 1016 8.72 ⎪

23 65.0 685 1020 7.07 ⎪

24 560 1021 6.78 ⎭

25 1090 1010 6.02 ⎫ 0.420

26 610 1017 5.97 ⎪

27 790 1016 6.83 ⎪

28 1100 1014 7.65 ⎬

29 650 1021 6.12 ⎪

30 65.0 630 1021 5.21 ⎪

31 660 1018 5.07 ⎭

June 1 65.1 920 1014 5.96

2 65.1 800 1013 5.81

3 65.0 950 1014 7.30

4 790 1015 6.78

5 780 1020 8.28

6 65.1 890 1015 6.89

7 720 1017 5.87

8 950 1015 5.93

9 1060 1014 4.96

10 940 1017 5.92

11 1050 1019 7.62

12 1000 1017 6.66

13 890 1021 7.26

14 1340 1016 6.91

15 1190 1015 6.86

16 720 1025 7.99

17 65.2 800 1017 7.25

18 820 1018 6.99

19 920 1014 6.18

20 890 1015 6.03

21 900 1016 6.37

22 760 1018 6.79

23 630 1020 6.06

Daily average from Oct. 26, 1903 833 1018 7.43 0.516 1.28

It will be seen by a study of the analytical data that Dr. Underhill had an average daily excretion of nitrogen through the kidneys from October 26, 1903, to June 23, 1904, of 7.43 grams. From October 26 to April 13, a period of nearly six months, the average daily excretion was 7.81 grams of nitrogen, while from the latter date to June 23 the average daily excretion amounted to 6.68 grams of nitrogen. Taking the body-weight at 65 kilos, the lower nitrogen figure would mean a metabolism of 0.102 gram of nitrogen per kilo of body-weight, closely akin to the figures obtained with the two preceding subjects.

An excretion of 6.68 grams of nitrogen corresponds to the metabolism of 41.75 grams of proteid matter, while the excretion of 7.43 grams of nitrogen implies the metabolism of 46.4 grams of proteid, being less than one-half the ordinarily accepted requirement for the healthy adult.

Notes in this chapter

Note 1 · All figures for nitrogen throughout the book, whether referring to food, urine, or fæces, were obtained by exact chemical analysis, using th Note 2 · All foodstuffs were analyzed from large samples, to diminish as much as possible the errors of analysis. Nitrogen was determined by the Kjel Note 3 · The fæces of this period were separated by lampblack. They were dried on a water-bath after admixture with alcohol and a little sulphuric ac