338 CO, Capacity of Blood. I 
The reliability of all,our work depends upon the accuracy with 
which the blood was “saturated” or (better) “equilibrated” with 
air containing 5.5 per cent CO.. The method of equilibration 
and analysis was therefore subjected to the following tests. 
A supply of arterial blood was drawn. Analysis was made for 
(a) the COs content. A sample was then equilibrated with air 
containing 5.5 per cent CO, and analyzed (6). A second portion 
of the blood was then equilibrated with air containing 10 per cent 
CO.. Part was analyzed (c), and the rest was then equilibrated 
with 5.5 per cent CO, and analyzed (d). <A third sample was 
equilibrated with atmospheric air. A part of this was then ana- 
lyzed (e), and the remainder was equilibrated with 5.5 per cent 
CO, and analyzed (f). In all cases the equilibration was carried 
out by the method used in routine ‘determinations of the CO, 
capacity. The equilibrating air was passed through a tube into 
a test-tube containing 2 or 3 ec. of blood under albolene until 
the liquid was violently agitated for 30 seconds and for the most 
part in foam. The test-tube was then stoppered and set aside 
until the blood and oil separated. 
The foregoing series of equilibrations and analyses was re- 
peated with blood drawn from the same dog several hours later. 
The equilibrations lasted 2 minutes each. The results obtained 
were as follows: 
a b c d € f 
Rirst “Series... fies eee eee 47 50 ~§»= 60 51 oe 50 
Second satis ig 7) Pe ee eee 47 47 58 47 oF 49 
Under the extreme conditions the concordances 50, 51, 50 in 
one series and 47, 47, 49 in the other (6, d, andf) are satisfactory. 
Object of the Hxperiments. 
Our aim was to determine the effect upon the CO, capacity 
of the blood induced by increasing the CO, tension of the pul- 
monary air. This was effected by depressing respiration by 
means of morphine or by administering CO: in proper dilution in 
the air breathed. . For the latter purpose a Douglas bag of 50 
liters capacity was filled with air to which 5 or 6 per cent of CO. 
. was added. The animal rebreathed this mixture through a 
