AJ^fD OTHEE PHENOMENA OE EESPIEATION. 
711 
from six minutes. I was unable to use the spirometer as well as the analytical appa- 
ratus whilst working the wheel, for I found the breathing too much oppressed by it ; 
and more particularly, since I was compelled to use a double set of the analytical appa^ 
ratus, on account of the rapidity of the current of the expired air which was forced 
through it. 
After the second inquiiy, I determined the state of the respiration m the fifteen 
minutes constituting the interval of rest. After leaving the wheel I sat down (after 
the manner of the prisoners), and with a loss of half a minute used the spirometer, and 
noted the quantity of air inspired per minute. The carbonic acid was also collected 
during seven minutes ; viz. during three minutes after four minutes’ rest, two minutes 
after ten minutes , and two minutes after thirteen minutes’ rest. The average quan- 
tity of carbonic acid thus obtained was 9T4 grs. per minute ; but that does not include 
the first four minutes of the period of rest, and the following statement shows that 
then the respu’ation was fast subsiding to the minimum quantity. From a considera- 
tion of the quantity of air inspired, I compute that the quantity of carbonic acid 
evolved during the first minute of rest was 25 grs., in the second 20 grs., and in the 
third 15 grs., and hence that the average of the whole fifteen minutes’ rest was 11-3 grs. 
per minute. 
The quantity of air inspii’ed in cubic inches per minute, commencing half a minute 
after the labour had terminated, was as follows, in each minute, in its order 1120, 
930, 720, 680, 590, 600, 540, 590, 530, 560, 540, 500, 560, and 520, yielding an average 
of 641 cubic inches per minute. It is e\ident that whilst there is, during the whole 
interval of rest, an increase in the respiratory changes over that of rest apart from this 
exertion, the great excess due to the exertion disappears after five minutes’ rest. 
The remark made already as to the influence of season over the eifect of exertion must 
not be forgotten. 
Resume. 
In the foregoing paper it has been shown — 
1. That it is possible to collect the whole of the carbonic acid exhaled by the lungs 
in the twenty-four hours, or for any period, however long or short. 
2. The quantity of carbonic acid expired in the twenty-four hours was, on the average 
of eight sets of inquiries in four adult males when in a state of rest, 26T93 oz. (7T44 
oz. carbon), of which 1950 gi's. were expired in the six hours of the night. The pro- 
portion per minute in the night and the day is 1 to 1-84. In light sleep 4-88 grs. per 
minute were exhaled, and 4-5 grs. is the estimated amount in profound sleep in July. 
The quantity of carbon exhaled in the twenty-four hours, by each of the subjects at rest, 
was 5'6 oz., 6'54 oz., 6'735 oz., and 7*85 oz. 
3. The quantity of air inspired during the working day of eighteen hours, was, to the 
carbonic acid expired, an average of 56*3 cubic inches to each grain. 
4. The rate of respiration was on the average 13'87, and of pulsation 71'7. The 
average depth of inspiration was 33-6 cubic inches. 
