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.