THE UTILIZATION OF ENERGY. 499 
Experiments on the Dog.—The following experiments by 
Zuntz,* while not the earliest upon record, may serve to illustrate 
the general methods employed and as introductory to the more 
elaborate experiments upon the horse. 
The following table shows the average oxygen consumption and 
carbon dioxide excretion, determined by the Zuntz apparatus, of 
a dog when lying, standing, and performing work upon a tread- 
power, and also the amount of work done, all computed per minute: 
i Respiration per Ww : 
. ork per Minute. 
Weight Minute. DP 
of cera Ne of 
ma. Ke Respir- | Work | Work | ,Dis- 
on Lets Oxy- | COs. | atory of of tance. 
Kee. ments. gen c.c. Quo- |Ascent: Draft, travel- 
8. ec. tient. | Kgm.| Kgm. led, 
Meters. 
6.) Dying woes ba8 names 174.3) 124.7) 0.71 |......]...... 
is (Magnus-Levy) ..} 172. | 123.8} 0.72 |......]...... 
2 |Standing . ........... 245.6) 170.2) 0.69 |......]...... 
26.932 8 Ascending shght incline. 725.3] 525.2) 0.73 13.23) 0 2 se: 78.566 
26.674 5 steeper * .{1285.3] 990.6) 0.77 |365.82)...... 79.497 
27.175 10 | Draft nearly horizontal .|1028.8] 798.9] 0.77 22.83]202.91| 70.420 
The work per minute as given in the above table does not in- 
clude the energy expended in horizontal locomotion. The work of 
draft is the product of the distance traversed into the draft; the 
work of ascent equals the same distance multiplied by the sine of 
the angle of ascent. A remarkable increase (41 per cent.) in the 
metabolism when standing over that when lying was observed 
(compare p. 343) but does not enter into the subsequent com- 
putations. 
The two experiments on ascending a grade afford data for com- 
putiig the increased metabolism corresponding, on the one hand, 
to one gram-meter of work done against gravity, and, on the 
other, to the transportation of one kilogram through one meter 
horizontally. The latter, of course, is not work in the mechanical 
sense, but it requires the consumption of a certain amount of 
material, the liberated energy being employed in successive liftings 
_ of the body and in overcoming internal resistances and ultimately 
appearing as heat. It includes, of course, the increased metab- 
olism required for the maintenance of the erect position. 
* Arch. ges. Physiol., 68, 191. 
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