106 STORRS AGRICULTURAL EXPERIMENT STATION. 
as compared to 778.6 grams in experiment 1 and 794.6 in expe- 
riment 2. In these three experiments the subject was either at 
rest or engaged in light mental work as reading. 
TABLE 9. 
Ventilation and CO, exhalation in four respiration experiments. 
Quantities of atr supplied in the ventilating current 
and of carbon dioxide exhaled. 
The COz in the incoming air ranged from .55 to .60 milligrams per liter. 

















Z, 6 2 CO, In OuTGoING AIR. |¥ fa fa 
4 4-5 AMOUNTS PER LITER. Bs 2 
= SUBJECTS AND EXPERIMENTAL PERIODS. Ee sO eal 
a, e me 
ow S | Min Max. Avg. < 4 _ 
| Liters. | Mgms. | Mgms. | Mgms. | Grams. 
Td, bt ).. ab test..24- davex - - -| 49 8:0 | 12.5: | TIvOmayaee 
oer t. O., atwest, 24 dayer « - - 50 8.1 | 12.7 | 1O2pae ogee 
aan Oo le eat light mental work, 5 days,| 75 4.6 9.9 7 ht SOO 24 
ee ‘period, at rest, 156 days, - 55 8.8 | 12.8 } 1OCss esAce 
y) | 2d period, at mental work, 3 days,| 55 87°) 12:8-| 1675S estes 
| 3d period, at rest, 3 days, - - 55 g.0° 1 12.5.) 10,6268 7iee 
4) = 1 4th period, at muscular w’k, 3days,) 55 9.9 | 24:6.) 160.8 41562 4m 
<i | 5th period, at rest, 134 days, - 55 10.9 |°13.4: /S1DG7 ano 
(eT otal s12idays.e ae - - 55 8.1.1 24.6 +p d23 34 oSo0e2 

Experiment No. 4 is of much more interest in this connec- 
tion, since the differences in mental and physical exercise were. 
much wider. During the first and fifth periods of 154 and 13 
days, respectively, the subject was at rest. During the second 
period, which lasted 3 days, he was engaged in rather severe 
mental work. ‘The third period was one of as nearly absolute 
rest as was practicable; in the fourth the subject was engaged 
in severe muscular work for 8 hours per day. ‘The rate of 
ventilation was 55 liters per minute. The temperature of the 
air in the chamber was generally from 19°-20° centigrade, 
though it fell at times to 17° and rose during the periods of 
hard muscular work to 22°. 
The weight of CO, given off in twenty-four hours ranged 
from about 850 to goo grams for the days at rest, and was no 
larger with mental work, but averaged over 1,360 grams for 
the days of muscular work. During two periods of six hours 
each of hard muscular work the elimination of CO, reached 
513 and 501 grams respectively. During the night or sleeping 
period the exhalation of CO, was singularly constant irrespec- 
tive of the day’s occupation. It amounted to 175 grams in six 
hours, with but slight variation from that figure. 

