OXYGEN -TENSION 



107 



The Carbon Monoxide Method 



Some years ago Haldane invented the following method 

 for finding the tension of oxygen in human blood. The 



B 



r^ ^ - "^< 



Fig. 23. — Krogh's microtonometer. A, lower part showing the gas 

 bubble; B, upper part showing the fine tube into which the 

 bubble is drawn for measurement. 



subject breathes air containing a known amount of carbon 

 monoxide. After a short time equihbrium is attained 

 between the CO in the blood and the CO in the alveoU. 



