518 PRINCIPLES OF ANIMAL NUTRITION. 
The very lame horse mentioned above gave a still higher figure, 
viz., 0.566 cal. 
A somewhat larger number of experiments with Horse No. XIII 
brought out the interesting fact that the increase in the metabo- 
lism caused by carrying a load on the back was markedly less than 
in the case of No. III, both at rest and in motion. 
PER KILOGRAM MASS (HORSE + LOAD). 
Without Load, With Load, 
cals. per Minute. | cals. per Minute. 
Standing : : 
Horse XTII......... 15.990 14.670 
A TTD 35. sa Genetics 18.311 18.389 
Walking horizontally : cals. per Meter. | cals. per Meter. 
Horse XIII......... 0.389 0.388 
ia 8 8 ERE are seme 0.367 0.391 
Trotting Horizontally : 
Horse XIII......... 0.553 0.488 
£6 TNT sa ashe gage 0.548 0.601 
While, without load, Horse No. XIII showed a greater metabo- 
lism, both while walking and trotting than did Horse No. III, the 
additional effort required for carrying a load was relatively less, 
so that in every case the metabolism per unit of mass, instead of 
increasing, remained unchanged or even diminished. The percent- 
age efficiency of the animal in ascending a grade was also not 
materially affected by the load, while with Horse No. III it ap- 
peared to increase slightly. 
The experiments with Horse No. II previously reported,* when 
recalculated + in the same manner as the later ones, likewise show 
interesting individual differences. For horizontal locomotion, 
after correcting for varying speeds, we have per kilogram mass 
(horse + load) the following: 
Horse No. II, Horse No. III, 
cals. per Meter. | cals. per Meter. 
Walking without load........ 0.415 0.367 
ae _ with load........... 0.385 0.391 
Trotting without load........ 0.499 0.548 
i with load........... 0.415 0.601 
* Landw. Jahrb., 18, 1. { Ibid., 27, Supp. ITI, 355. 
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