512 PRINCIPLES OF ANIMAL NUTRITION. 
Kinp oF Work.—Of the forms of work investigated, that of 
ascent, that is, of raising the weight of the body (with or without 
load), appears to be the one which is performed most economically. 
The horse in ascending a moderate grade without load showed an 
efficiency of 34.3 per cent., while with a load of 127 kgs. a slightly 
higher efficiency was obtained, viz., 36.2 per cent. (The latter 
figure, however, includes some estimated corrections for speed.) 
For the dog (p. 502) the average result was 30.7 per cent. For 
man the figures of the table on p. 503 correspond to from 28.1 to 
36.6 per cent. 
The efficiency, however, was found to decrease with the steep- 
ness of the grade. Thus with the horse it fell from 34.3 to 33.7 
per cent., with an increase of the grade from 10.7 to 18.1 per cent. 
The experiments of Loewy on man, averaged on p. 503, show the 
same result in a more striking manner. Taking separately the 
experiments on each subject we have the following: | 
Efficiency. 
Grade 
Per Cent. 
A. L. re ie LZ 
Per Cent. Per Cent. Per Cent. 
23 34.3 36.1 36.6 
30.5 34.3 32.6 36 6 
36.6 29.0 32.3 32.2 
The work of horizontal locomotion consists largely of successive 
liftings of the weight of the body. It might therefore be expected 
from the above results that this work would be performed even more 
economically than that of ascent, since it is obviously the form of 
muscular activity for which animals like the horse and dog are 
specially adapted. In the case of the walking horse, Kellner * has 
proposed a formula. based on mechanical considerations, for com- 
puting the work of locomotion. Zuntz + has applied this formula 
to the animal used in his experiments and computed the mechanical 
work of locomotion at the three speeds for which the total metabo- 
lism was also determined (p. 507). 
Landw. Jahrb., 9 658. 
ft Ibid , 27, Supp IIL. p 314. 
