98 MUSCULAR WORK 
to over 100 miles (161 kilometers) of riding. In other words, this man took 
what might be called a "century run" before breakfast, an evidence of his 
staying power that, to say the least, is rather remarkable. 
It is furthermore of interest to cite the heroic experiments of Lusk ° 
and his associates in which an effort was made to remove the glycogen from 
the body. Having shown that experiments in which phlorizinized dogs 
were exposed to cold indicated the removal of the residual glycogen, they 
attempted to exhaust the human body of glycogen by the same means, using 
cold baths. Although Lusk's report of these experiments with men indicated 
that cold per se was the predominating factor in producing this effect, per- 
sonal discussion with him leads to the belief that he considered the cold of 
moment chiefly for the stimulation of shivering, this intense muscular ac- 
tivity using the muscles all over the body. It was hoped by this means to 
deprive all the muscles of glycogen. The abnormally high post-absorptive 
values obtained for the respiratory quotient with both person A and person B 
after a rather rigid carbohydrate-free regime lead one to suspect errors in 
these determinations. The greatest increase in the heat production brought 
about by the cold baths was 188 per cent above the normal with person B, 
or 645 c.c. of oxygen per minute as compared with 224 c.c. of oxygen consumed 
while resting. Applying these figures to person A, although as a matter of 
fact the measured heat production after shivering was but 63 per cent higher 
than normal, we find from the protocols of the experiment that this subject 
shivered 18 minutes during the first bath and 19 minutes during the second, 
or a total of 37 minutes of shivering. Assuming that the metabolism was not 
188 per cent, but 3 times that of normal, and that the resting metabolism for 
a man of this weight would be 76 calories per hour, under conditions of shiver- 
ing the metabolism would be 228 calories per hour, or 141 calories in 37 min- 
utes. If the total combustion during this time were exclusively of glycogen, 
this would correspond to about 33 grams of glycogen. 
With our professional subject M. A. M., the initial respiratory quotient 
during work was not far from 0.90 and remained constant throughout the 
experiment. With person A in Lusk's experiments the initial quotient of 
0.99 would lead one to believe that there was a surplus of glycogen at the 
beginning of the experiment, and yet according to the computations it ap- 
pears that only 33 grams could possibly have been removed during the ex- 
perimental period. It would seem highly improbable, therefore, that the 
body could be deprived of glycogen by shivering which continued not more 
than 37 minutes when the metabolism was no greater than three times that 
of normal; for while unquestionably shivering brings into play a larger 
number of muscles throughout the whole body than does bicycle riding, it 
is clear from the results obtained in our research that the severe muscular 
work incidental to prolonged bicycle riding removes a very much larger 
amount of glycogen from the body. 
Urine Excretion in Experiments with Muscular Work. 
The difficulties incidental to securing the proper collection of urine 
during experiments with severe muscular work have already been pointed 
out. The profuse perspiration, the nervous excitement incidental to the bi- 
° Lusk, Am. Journ. Physiol., 1911, 27, p. 427. 
