DR. A. GAMGrEE ON THE ACTION OF NITRITES ON BLOOD. 
609 
Gas taken (CO) measured 44’359 cub. centims. at 0° C. and 0 m, 76 
Carbonic acid exhaled=6 , S vols. = 07 cub. centim. „ 
Oxygen exhaled =0*5 vol. = (H)5 cub. centim. „ 
The apparent increase in the volume of gas after contact with the mixture of blood 
and nitrite of amyl is due to the tension of the vapour of the nitrite of amyl. The 
amount of oxygen exhaled by the blood is quite insignificant. 
Exp. IV. In the last experiment it was pointed out that the volume of gas appeared 
to have increased after contact with the blood ; this was, however, due to the tension of 
the vapour of nitrite of amyl. It is a curious fact that when carbonic oxide acts upon 
blood, although very considerable changes take place in the composition of the gas, its 
volume is almost imperceptibly affected. I shall in a separate paper, devoted to the con- 
sideration of the relation which the volume of carbonic oxide absorbed by blood bears 
to that of the gases exhaled, point out how this insignificant change in volume can be 
explained. At present it will suffice to remark that, since the volume of gas does not 
change materially, we may bring it in contact with blood, agitate it thoroughly, and then 
take a fraction of the gas and analyze it without having to wait for many hours to have 
elapsed, as is the case in the first experiments on the action of atmospheric air upon 
blood. In the latter, as the gas is very liable to change in volume, we are obliged, 
after agitating the blood with air, to wait for a considerable number of hours so as to 
allow of such a subsidence of froth as will enable us perfectly to separate the gas from 
the fluid. In these experiments, as the volume of the gas in contact with the blood 
alters considerably, mere percentage analyses do not suffice to show to what extent the 
gas has been altered in composition, whereas in those in which atmospheric air is replaced 
by carbonic oxide, we may dispense with a measurement of the gas after action, and rest 
satisfied that, by a determination of the percentage composition, we shall obtain a full 
insight into the changes which have occurred. The ground upon which this assertion 
is based will be seen by reference to the analyses and experiments which I quote in a 
paper “ On the Relation which the volume of CO absorbed by Blood bears to that of 
the O displaced.” 
In the experiments now to be described, recently defibrinated blood, which had been 
arterialized by shaking with air, was brought in contact with a measured volume of pure 
carbonic oxide. Having been agitated for the space of half a minute, and then left in 
contact with the blood for one hour and twenty minutes, the gas was decanted and the 
amount of oxygen which had exhaled was determined. Then the same quantity of the 
blood mixed with nitrite was treated in exactly the same manner, and the changes which 
occurred in the composition of the gas which had been added to it determined. 
(a) Normal Hood. 
Vol. of Hood used 20 cub. centims. 
Vol. of CO taken 468-5 vols. =41-03 cub. centims. 
Vol of gas analyzed . . 315 vols. 
After absorption of C0 2 . 313 „ 
After absorption of 0 . . 305 „ 
(6) Blood and Nitrite. 
25 cub. centims. of tbe same blood as was used in 
(a) were treated with 5 cub. centims. of water, con- 
taining 0-05 grm. of UNO, in solution. 
20 cub. centims. of tbe mixture brought in contact 
with the gas and left in contact for one hour and 
twenty minutes. 
