76 
The average amount of metabolic nitrogen in the feces in the 
experiments with the three subjects was 42.0, 32.1, and 2-t.l per rent, 
respectively, or a general average of 32.7 per cent, a value which 
agrees very closely with that found by Woods and Merrill a for a man 
on bread and milk diet, viz, 32 per cent. In later experiments not 
yet published the same authors with a different method of examina- 
tion obtained much higher results. They state, however, that they 
consider that the ether, alcohol, and limewater method yields the most 
trustworthy results. 
It would seem desirable and necessary to accumulate more data 
regarding metabolic nitrogen before drawing any definite conclusions. 
PECUNIARY ECONOMY OF FRUITS AND NUTS. 
The object of this discussion is to present one side of the pecuniary 
economy of food, especially fruit and nuts. The composition and 
digestibility of nuts and fruits has been discussed in the foregoing 
pages, but little has been said regarding their comparative cost as 
sources of nutrients and energy. 
The table below shows the comparative cost per pound of the total 
protein and per 1,000 calories of energy when furnished by different 
fruits and nuts and food products derived from them, and also the 
amount of nutrients and energy furnished for 10 cents rating the 
foods at certain average prices per pound. For purposes of com- 
parison a few of the more common foods have been included also. As 
already noted, fruits contain very little protein, therefore no matter 
how low the price of the fruit per pound the cost of the protein must 
of necessity be high. Nuts, on the other hand, being rich in protein, 
would supply this nutrient at a much lower cost. The principal nutri- 
ent in fruits belongs to the group carbohydrates. Nuts are rich in 
fats. Both fruit and nuts therefore are sources of energy, the amount 
varying within rather wide limits. 
Table 56. — Comparative cost of total nutrients <>n<1 energy <n different food materials at 
average prices. 
Kind of food material. 
Fresh fruits: 
Apples 
Apricots 
Bananas 
Cantaloupes 
Cherries 
Figs 
Grapes 
Lemons 
Limes 
Nectarines . . 
Amounts for lu cents 
Price 
per 
pound. 
Cost of Cost of 
1 pound 1,000 
pro- calories 
tein. energy. 
Total : 
weight 
of food 
mate- 
rial. 
Pro- 
tein. 
Fat. 
Carbo- 
hy- 
drates. 
Energy. 
Cents. 
1] 
3 
Dollars. 
5.00 i 
3.00 
B. 7.', 
11.67 
4.45 i 
4.67 
4.00 
10.00 
3. 57 
Cents. Pounds. Pounds. Pounds. 
11.8 
23.3 
38.9 
11.6 
18.4 
11.9 
48.3 
17.2 
6.67 
3.33 
1.43 
2.86 
2. 50 
1.43 
2.50 
1.43 
4.00 
8 13.33 28.1 , 1.25 
0.02 
.03 
.01 
.01 
.02 
.02 
.03 
.01 
.03 
.01 
0.02 
.02 
. 03 
.02 
Pounds. 
0.72 
.42 
.21 
.13 
.40 
.27 
.36 
.08 
.24 
.19 
Calories. 
1,467 
849 
429 
257 
862 
543 
837 
207 
580 
356 
" U. S. Dept. A^rr., Office of Experiment Stations Bui. 85. 
