138 
During- the rest experiments, in which the subjects had as little 
muscular activity as possible, there was but little difference in the 
elimination of carbon dioxid during the two day and first night periods. 
In the 9 experiments with E. O. the average rate per hour during 
these three periods was 37.9, 37.4. and 36.2 grams, respectively. In 
the experiment with A. W. S. there was a slightly larger amount of 
carbon dioxid eliminated in the first two periods than in the third 
period, the rates being 39.8, 37.1, and 32.8 grams, respectively. In 
the 1 experiments with J. F. S. the elimination during the first three 
periods averaged 37. 36.1, and 31.6 grams per hour, respectively. 
During the second night period, when the subject was generally asleep 
for nearly the whole time, the output fell off with E. O. to 22.3, with 
A. W. S. to 23.2, and with J. F. S. to 22.3 grams per hour. Not only 
are the averages with the 3 men in close accord, but the range of varia- 
tion in the different da} T s and experiments is decidedly narrow for all. 
In the average of the 13 experiments the proportion given off in each 
of the four periods of the da} 7 is 28.6, 28.1, 26.1, and 16.9 per cent, 
respectively. 
The elimination of carbon dioxid in the two day periods of the work 
experiments was more than twice as large as in the two day periods 
of the rest experiments. With E. O. the average amounts given off 
were 78.4: grams in the first and 79.5 in the second day period when at 
work, as compared with 37.9 and 37.1 grams, respectively, when at 
rest. With J. F. S. the amounts averaged 73.6 and 74.7 grams in the 
day periods of the work experiments, as compared with 37 and 36.1 
grams in the corresponding periods of the rest experiments. The 
elimination in the two night periods averaged with E. O. 38.1 and 23.1 
grams in the work experiments, as compared with 36.2 and 22.3 grams 
in the rest experiments, the differences being small; with J. F. S. 
the amounts w x ere practically identical, being 31.3 and 22.3 grams in 
the work experiments, as compared with 31.6 and 22.3 grams in the 
rest experiments. 
The uniformity in the amounts of carbon dioxid given off during 
the second night period in all the experiments is very noticeable. 
Such data ma} T perhaps be taken as an approximate measure of the 
metabolism of carbon in the body of an active healthy man when at its 
lowest ordinaiy ebb. 
ELIMINATION OF ENERGY. 
Measurements of energy. — The kinetic energy given off by the body 
is measured in these experiments as the sum of three quantities: (1) The 
heat taken up by the water current in its passage through the cham- 
ber; (2) the latent heat of the water vapor given off by the body — i. e., 
of the water vaporized by its heat and carried out in the air current, 
