Determination of Oxygen in Blood. 



85 



troduced (the cyanide solution is made air-free by boiling or 

 by shaking in an evacuated flask, and is kept in a burrette under a 

 layer of paraffin oil two or three centimeters thick to exclude air). 

 The apparatus is now evacuated, shaken and the oxygen set free 

 determined exactly as is carbon dioxid. The solubility of oxygen 

 in water is so slight that no correction is made for what remains in 

 solution. The only correction necessary is for the small amount 

 of nitrogen gas which 2 c.c. of blood contain. 



