516 PRINCIPLES OF ANIMAL NUTRITION. 
man, while in the dog it is apparently somewhat less, as is seen 
from the following comparison: 
Grade, Efficiency, 
Per Cent. Per Cent. 
Man 5 geicar suas cee 23 35.7 = ~ 
MOPS vain su aang’ arete 10.7 34.3 
ae ee eee 18.1 . 33.7 
DOg sieves ew vee cee 17.2 30.7° 
The energy expended in horizontal locomotion, on the other 
hand, showed more marked differences, viz.: 
Energy Expended 
Speed, Met 
| per Minute. re ee 
DOR seis doweneccats 78.57 0.501 
Manigiectin scons oie 42 .32-74.48 0. 211-0 .334 
Horses jis cies aed 78.00 0.138 
The relatively high figure for the dog is perhaps due in part to the 
considerable muscular effort apparently required (p. 499) to main- 
tain the erect posture. It has been shown by v. Hésslin,* however, 
by a mechanical analysis of the work of locomotion, that the latter 
does not increase as rapidly as the weight of the animal, but in 
proportion to its two-thirds power, or, in other words, approximately 
in proportion to the surface. If we compare the experiments upon 
different species of animals on this basis—that is, if we divide the 
total energy expended by the animal for locomotion by the product 
of the distance traversed into the two-thirds power of the weight 
—we obtain the following figures: 
DOR essraco oi iiaietateate ihe oes Peeters 1.501 kgm. 
Matt oceania eared semoxe 0.861-1.274 kom. 
HOSE ssasptns scutes secede cieareese olay dias 1.058 kgm. 
Computed in this way, the figures for the horse and those for man at 
a comparable speed (74.48 M. per min.) do not differ greatly, and 
v. Hésslin’s conclusions are to this extent confirmed. The figures 
for the dog still remain higher than the others. If, in the case of 
* Archiv f. (Anatomie u.) Physiol., 1888, p. 340. 
