APPLICATIONS OF GAS ANALYSIS. 
V. BLOOD GAS ANALYSIS. 
By YANDELL HENDERSON anp ARTHUR H. SMITH. 
(From the Physiological Laboratory, Yale Medical School, New Haven.) 
(Received for publication, October 30, 1917.) 
The method to be described here is essentially a modification 
of that of Barcroft and Haldane (1) and of that described in the 
first paper of this series (2). The solutions employed are: (1) 
dilute ammonia (1 cc. of concentrated ammonia in 500 cc. of 
distilled water) kept tightly stoppered to avoid absorption of 
CO, from the air (or freed from carbonate with barium hydroxide 
and ammonium sulfate (8) ). <A little saponin is dissolved in the 
ammonia solution when an oxalate is used to prevent the blood 
sample from clotting. (2) A 10 per cent solution of potassium 
ferricyanide. (3) A 20 per cent solution of tartaric acid. | 
The apparatus used consists (1) of a Haldane gas analyzer in 
either its original or modified form (4), and (2) a small tube 
such as is shown in Fig. 1. 
Oxygen Analysis. 
The stop-cock of the diffusion tube is closed (7.e., turned to 
connect the side and end nipples); 1.5 cc. of the ammonia solu- 
tion are placed in the tube; and 1 cc. of the blood to be analyzed 
is introduced below the ammonia by means of a pipette. A short 
close fitting rubber stopper is inserted in the large end. A hy- 
podermic needle (disconnected from its syringe) is passed through 
this stopper to allow the escape of the air compressed by the 
insertion of the stopper. The needle is withdrawn, and the tube is 
rotated gently to mix the blood and ammonia until the corpuscles 
are completely laked. A small all glass syringe fitted with a 
hypodermic needle is then filled with the ferricyanide solution 
and the air is expelled. The needle is then thrust through the 
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