120 



METHODS FOR THE ANALYSIS OF BLOOD 



stopper to allow the escape of the air compressed by the 

 insertion of the stopper. The needle is withdrawn, and the 



FIG. 6. Rotating Apparatus. (Jour. Biol. Chem., 1918, 33, 41.) 



tube is rotated gently to mix the blood and ammonia until 

 the corpuscles are completely laked. A small, all-glass 



syringe fitted with an hypodermic 

 needle is then filled with the 

 ferricyanide solution and the air 

 is expelled. The needle is then 

 thrust through the rubber stopper 

 until the point projects in the 

 interior of the tube, and 0.25 c.c. 

 of the ferricyanide solution are 

 injected. The needle is then care- 

 fully withdrawn. 



The tube is now placed for five 

 minutes in a rotating apparatus 

 (Fig. 6) consisting of a block of 

 wood turning on an iron rod and 

 belted to a slowly moving motor 

 or shafting. There are a number 

 of holes bored in the sides of the 

 block of wood into which diffusion 



FIG. 7. -A, Gas Burette of Analy- tubes can be inserted. The rate' 

 zer; B, Diffusion Tube; C, of revolution should be not more 

 Beaker of Water. (Jour. Biol. than 40 or 50 times a minute. 

 Chem., 1918, 33, 43.) During the rotation the contents 



of the tube spread in a thin film 



along the walls and allow complete diffusion of the liberated 

 oxygen into the air of the tube. 



The tube is next connected glass to glass with the gas analyzer 

 by a short piece of heavy rubber tubing in the manner shown in 



