THE UTILIZATION OF ENERGY. 503 
Energy Expended in 
prey Hono 
Experimenter. Appara- anes bah Grade, 
pene | ieee | eettam. | Pe, | Santa 
Kegs. per Kg. Nees t Meters. 
and Meter, K ae 
Kem. gm. 
Katzenstein .......... 55.5 0.334 2.857 74.48 | 9.6-13.3 
f aaa 0.217 3.190 71.32 ) 6.5 
z 0.211 3.140 71.46 . 
Schumburg & Zuntz{| 39°9 | o'ass | 3.563 | 41.93] jstons 
| 88.2 | 0.263 | 3.555 | 43.34 5 |90-7-62.0 
72.6 0.284 2.913 62.04 
Loewy...........--- 81.1 0.231 2.921 60.90 }|23.0-30.5 
80.0 0.244 2.729 56.54 
Frentzel: 
Normal gait.........]/ 86.5 0.219 Le 746 66.94 
Slow Osseo wages  Sb5 0.233 : { 3..92 
Reach: i 23.3 
Normal gait.........| 65.8 0.230 63.95 
Slow “.........| 55.8 | 0.251 {2.846 { 34.58 
of computing the total metabolism in the rest experiments has 
been explained; it remains to consider the results of the work 
experiments. The larger proportion of the experiments were 
upon the same horse (No. III), and the summaries and averages 
on subsequent pages represent chiefly the results with this animal. 
The work was done upon a special tread-power located in the 
open air, and during the rest experiments the animal likewise stood 
in the tread-power. The inclination of the platform of the power 
could be varied, and it could also be driven by a steam-engine, so 
that by setting it horizontal the work performed by the animal was 
reduced to that of locomotion alone. The distance traversed was 
measured by a revolution-counter, and in the experiments on draft 
the animal pulled against a dynamometer. 
The large number of experiments (several hundred) are grouped 
by the authors into fourteen periods according to the season (winter 
or summer) and the kind and amount of food consumed, each of 
these periods including a considerable number of experiments both 
on rest and on different forms of work. On each day from two to 
eight experiments were usually made, some on rest and some on 
work of various sorts. The average of all the rest experiments in 
each period is then compared with similar averages for the various 
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