
DEMANDS OF THE BODY FOR NOURISHMENT. 125 
amounts actually used by the body when the subject had a 
minimum amount of exercise and when he was engaged in de-- 
cidedly active muscular work. 
The materials actually oxidized in the body are the digested 
nutrients of the food minus the protein or fat gained or plus 
the protein or fat lost by the body. ‘The data thus show very 
clearly the demands of the body under the different conditions 
and the increase in the demand which accompanied the per- 
formance of muscular work. 
The respiration calorimeter experiments bring out very clearly 
the effect of muscular exercise upon the katabolism of matter 
and energy in the body and the consequent demand for food. 
Take for instance the case of one of the subjects, J. C. W., 
who like the others was a young, healthy, active man. When 
he was at rest in the calorimeter his body transformed only 
about 2,350 calories of energy per day. Hight hours work in 
driving a stationary bicycle increased this to an average of 
5,120 calories. This work he did not find especially severe. It 
appeared that the increase of material and energy used was di- 
rectly proportional to the muscular work performed. On this 
basis, four hours pedalling of the bicycle would have increased 
the transformation of energy from 2,350 to 3,735 calories. Mr. 
W. was a man of rather large size, a student in college, quite 
inclined to athletic exercise and seemed to be a reasonably lib- 
eral but not excessive eater. In the rest experiment in the 
chamber of the respiration calorimetér he had extremely little 
exercise and his body transformed only the 2,350 calories of 
energy just mentioned; but the moment he used his muscles 
for active work, the katabolism increased from a rate below 
that which the standards suggested beyond prescribes for a 
man without muscular exercise, to a rate about equal to that 
of the proposed standard for a ‘‘man with very hard muscular 
work.’’ | 
These experiments simply show the quantities of material 
and energy metabolized by a small number of men under spe- 
cific conditions of work and rest. Though their bearing upon 
the general subject of dietary standards can be more advan- 
tageously discussed in detail when it shall be possible to take 
into account not only these and other experiments with men in 
