546 PRINCIPLES OF ANIMAL NUTRITION. 
than 400 revolutions. Comparing the averages of these two groups, 
they obtain the following: 
eee Toss of 
fs 
penta. Work, Kem. Weight. 
Grms. Grms. 
Heavier work (18 experiments) Sleile te ceaeata 6236 1,415,755 179.5 
Lighter “ (13 Jiccieye nies aie 5851 995,225 7.3 
DifferenGe.oso5cs-che hatecesda eke wae ey 385 420,530 172.2 
Correction for loss of weight............)...-. pie 231,922 
188,608 
According to this computation, the 385 grams of added nutrients 
enabled 188,608 kgm. of work to be performed. At 3.96 Cals. per 
gram the metabolizable energy of the added nutrients equals 1524 
Cals. From this, according to Zuntz & Hagemann, is to be de- 
ducted 9 per cent. for the work of digestion and also 2.65 Cals. 
for each gram of total crude fiber in the added food. On this 
basis we have the following: 
iene” se 
Digested nutrients.............. 385 1524 
Average crude fiber fed: 
Heavier work ............... 2338 
Lighter work................. 2356 
Difference. ................ —18 
Equivalent energy..........).......00. ' —48 
Work of digestion (1524 X 0.9)..J.......... | 137 
Deduction siicceecsceiuwancresacs| adanesagats 89 
Available energy.............00)e cee eee eee 1 1435 
Work done (188, 608 + 424)......).....0000. 445 
The work done is 31 per cent. of the computed available energy of 
the food, a figure corresponding very closely with the 31.3 per 
cent. found by Zuntz & Hagemann. 
The difference in the average amount of crude fiber fed in the 
two groups of experiments is so small that the estimate for the 
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