DR. A. GAMGEE ON THE ACTION OE NITRITES ON BLOOD. 
615 
was admitted into the heated blood-receptacle the evolution of gases is most rapid. 
Very soon, however, the bells of gas become fewer and fewer, and in about twenty-five 
minutes after the pumping has been commenced the process is virtually at an end. 
For the sake of greater accuracy I have in my experiments generally exhausted the 
blood for one hour. 
At the end of this time the blood-receptacle and the first bulb contain a dry red mass ; 
the second bulb contains a little fluid blood which has spirted over, whilst the U-tube 
contains the greater part of the water of the blood which has condensed there. Some 
of this is also deposited in the large bulb situated between the U-tuhe and the Sprengel 
aspirator. 
After describing separately my experiments, I shall draw attention to some interesting 
facts connected with the use of the Sprengel tube as a blood-pump, and show that the 
success of my experiments throws doubt upon statements which have lately been made 
in reference to the conditions which are most favourable for the extraction of gases 
from the blood. 
In order that the observations which have been made upon the gases of blood treated 
with nitrites should be understood, and to prove the accuracy and value of the methods 
used, I must quote some analyses of blood to which no nitrite was added. 
I. In this experiment the gases were determined in venous blood obtained from the 
right side of the heart of a dog. Having exposed the external jugular vein, I passed a 
catheter into the right auricle, and when this had been completely filled with blood, its 
free extremity was inserted into the india-rubber tube attached to the glass tube leading 
into the blood-receiver. On opening the clip the blood flowed rapidly into the vacuous 
receiver. 
The quantity of blood admitted was 21*52 grms. The pumping was carried on for 
three quarters of an hour. There was no trace of gas then coming off. At the end of 
that time the 21*52 grms. of blood had been, through evaporation, reduced to 8*648 grms. 
The following Table exhibits the amount and composition of the gases obtained. 
Gases evolved by 100 volumes of the blood of the right side of the heart of a Dog 1 . 
At 0° C. and 0 m '76 pressure. 
At 0° O. and 1 metre pressure. 
Total gases 
66-03 vols. 
47*59 vols. 
Oxygen 
12*76 „ 
9*19 „ 
Carbonic acid 
49-95 ,, 
36-00 „ 
Nitrogen 
3-32 „ 
2-40 „ 
II. In this experiment defibrinated and well-arterialized blood of the Sheep was 
analyzed. 
1 I have thought it well to state the volume of gases obtained at 1 metre pressure, as well as at 0 m, 76, as the 
majority of the German experimenters who have lately made determinations of the gases of the blood have calcu- 
lated the volumes at 0° C. and 1 metre. 
4 p 
MDCCCLXVIII. 
