THE UTILIZATION OF ENERGY. 537 
Wolff’s conclusions from these results * are— 
1. The digested crude fiber is apparently valueless, both for 
maintenance and for work production. 
2. The remaining nutrients may be regarded as of equal value 
whether derived from grain or coarse fodder. 
3. The maintenance of a 500-kg. horse requires approximately 
3350 grams per day of fiber-free nutrients. 
Wolff’s subsequent experiments up to 1891 ¢ gave results con- 
firmatory in general of the above conclusions. Particularly was 
this the case when the work of locomotion was computed by Kell- 
ner’s formula and not by the formula a(—)* The work done 
(expressed in number of revolutions of the dynamometer) per 100 
grams of fiber-free nutrients was reasonably uniform and agreed 
well with the results previously obtained, while the fiber-free 
nutrients required for maintenance likewise agreed with the results 
given above. On the other hand, the inclusion of the digested 
crude fiber in the computations gave in many cases strikingly 
discordant results. In view of the unreliability of the measurement 
of the work no conclusions can be drawn as to the percentage 
utilization of the energy of. the food, and it seems unnecessary to 
describe the individual experiments. 
A discussion by Wolff t of the results of some of the experi- 
ments by Grandeau in which work was done, although rendered 
uncertain by the difficulty in estimating the work of locomotion at 
varying velocities, and by the changes in live weight of the animals, 
seems to indicate that they also confirm Wolff’s conclusions. 
SIGNIFICANCE OF THE Resu.tts.—In drawing his conclusions 
Wolff is careful to say that the digested crude fiber is apparently 
valueless, and while calling attention to Tappeiner’s then recent 
results on the fermentation of cellulose in the digestive tract as 
probably explaining its low nutritive value he points out that 
other ingredients of the food may also undergo fermentation. He 
therefore holds fast to the fact actually observed, viz., the lower 
nutritive value of the digested matter of coarse fodder compared 
* Loc. cit., p. 95. 
} Landw. Jahrb., 24, 125-192. 
t Ibid., 16, Supp. ITI, 110-126. 
