RESPIRATION 



401 



can be carried out with very simple apparatus, easily put together in any 

 laboratory, and suitable not only for exact research, but for use by 

 students. The chemical facts on which the method is based have already 

 been referred to in Chapter IV. 



The apparatus is shown in Figure 101 and the process is as follows. 

 Twenty cc. of the oxalated or defibrinated blood thoroughly saturated 

 with air by rotating it in a large flask, are measured out from a pipette 

 into the bottle A, which has a capacity of about 120 cc. 



Figure 101. 



Apparatus for determining the oxygen capacity of haemo- 

 globin in blood. 



As it is important to avoid blowing expired air into the bottle, the 

 last drops of blood are expelled from the pipette by closing the top and 

 warming the bulb with the hand. In filling the pipette, care must also be 

 taken that the corpuscles have not had time to begin to subside in the 

 vessel from which the pipette is filled. Thirty cc. are then added of a 

 solution prepared by diluting ordinary strong ammonia solution, (sp. 



