MENDEL.

Date.		Body-weight.	Urine.
Date.		Body-weight.	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 Taken in.		Nitrogen in Urine.		Weight of Fæces (dry).
Feb.	9	7.63	grams.	7.52	grams.
	10	6.77		6.75
	11	8.62		6.71
	12	8.83		8.24		53 ⎫	contain 5.84% N	=	6.248	grm. N.
	13	7.31		7.83		54 ⎭	contain 5.84% N	=	6.248	grm. N.
	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 Taken in.		Nitrogen in Urine.		Weight of Fæces (dry).
May	18	8.668	grams.	6.06	grams.	14	grams.
	19	6.474		7.17		39
	20	6.691		6.33		30
	21	8.345		6.78		83	contain 6.06% N	=	5.03	grm. N.
	22	7.015		5.70
	23	9.726		5.75		38
	24	10.424		6.39		57
						95	contain 5.76% N	=	5.47	grm. N.
									10.50	grm. N.
		57.343		44.18	+	10.50	grams nitrogen.
		57.343	grams nitrogen.		54.68	grams nitrogen.

Nitrogen balance for seven days	=	+2.663	grams.
Nitrogen balance per day	=	+0.380	gram.

Average Intake.

Calories per day	2448.
Nitrogen per day	8.192 grams.

In this period of seven days the average daily intake of nitrogen was 8.192 grams, or only 0.36 gram per day more than in the first balance period, while the average fuel value of the food amounted to 2448 calories per day. Yet the average daily output of nitrogen through the urine for this period was 6.31 grams, or 1.2 grams per day less than in the first balance experiment. Further, under the conditions of this balance experiment, the body was laying up 0.380 gram of nitrogen per day, i. e., showing a plus balance of 2.66 grams of nitrogen for the seven days’ period. Again, it is to be noted that the average daily amount of nitrogen metabolized, 6.31 grams, was 0.22 gram less than the average daily nitrogen excretion for the entire seven months’ period, 6.53 grams. Evidently, this subject was quite able to maintain nitrogen equilibrium with a metabolism of only 6.31 grams of nitrogen per day, on a daily diet having a fuel value of about 2400 calories. Indeed, taking into account the amount of the plus nitrogen balance, it is evident that the daily food was somewhat in excess of the real requirements of the body, under the then existing conditions of body-weight and bodily activity.

Again, we would call attention to the thorough utilization of the food in this experiment, emphasizing at the same time the voluminous character of the diet, together with its largely vegetable nature. The contrast between the diet made use of by Dr. Mendel and that used by the subject of the first experiment is quite striking, since the latter employed a much more concentrated diet with an average fuel value of only 1600 calories. Yet with a total intake of 57.343 grams of nitrogen for the seven days of Dr. Mendel’s balance period, 10.5 grams only passed out through the rectum, or 18.3 per cent, while in the second nitrogen balance of the first subject, with the more concentrated diet, 17.1 per cent of the total ingested nitrogen appeared in the fæces. In view of the great divergence in the character and volume of the intake, it is rather remarkable there should be so little difference in the relative utilization of the two diets.

Finally, taking the average daily excretion of nitrogen through the kidneys from November 10 to June 23, as a measure of the nitrogen metabolized daily, viz., 6.53 grams, and taking the body-weight at 70 kilos, it is plain to see that the nitrogen metabolized per kilo of body-weight throughout this experiment was 0.093 gram, closely similar to the result obtained with the first subject. In other words, both of these subjects, though widely different in body-weight, under different degrees of physical activity, and living on different forms of diet, seemingly required for the maintenance of equilibrium essentially the same amount of nitrogen per kilo of body-weight; viz., with the first subject 0.0947 gram, if we take the lower figure of the last two months, and 0.093 gram with the second subject.

Regarding the fuel value of the daily food, Dr. Mendel with a body-weight of 70 kilos, during the second balance period, apparently utilized on an average 34.9 calories per kilo of body-weight daily, while the first subject, of 57 kilos body-weight, made use of only 28 calories per kilo. The fuel value of the daily food must, however, as is well known, vary greatly with differing degrees of physical activity, from which arises the necessity for corresponding variation in the amounts of non-nitrogenous foods ingested.

Dr. Frank P. Underhill, instructor in physiological chemistry in the Sheffield Scientific School, is another subject of experiment who volunteered to study on himself the effects of a lowered proteid intake. Prior to the experiment he was in the habit of eliminating from 16 to 16.5 grams of nitrogen per day through the kidneys, representing the usual 105 grams of proteid food metabolized.

Dr. Underhill, at the beginning of the experiment, July 1, 1903, was twenty-six years of age and weighed 67.6 kilos. For a period of two weeks, from July 14 to August 2, he gradually reduced the intake of proteid food as well as the total amount of food consumed, doing this in part by diminishing the quantity eaten at breakfast, and in smaller measure at the two other meals of the day. During this period of two weeks, the urine and fæces were analyzed with the results shown in the accompanying table. Regarding the extent of proteid metabolism, it will be seen that the nitrogen content of the urine fell from 14.28 grams per day down to 5 to 6 grams per day. Having reached this level, the subject maintained it throughout the summer of 1903, occasional analyses being made to demonstrate the level of nitrogen excretion.

Date.		Body- weight.	Urine.			Fæces.			Total Nitrogen.
Date.		Body- weight.	Volume.	Sp. Gr.	Nitrogen.	Moist.	Dry.	Nitrogen.	Total 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.