Physiological Economy in Nutrition

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.