500 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



The oxygen capacity is determined in the same way, but 25-30 

 c.c. of the blood are first saturated with oxygen by spreading over the 

 surface of a large flask without producing a froth. 



37 cc. are given off by 20 c.c. of normal blood containing 13-8 per 

 cent, of haemoglobin. 



A better and more sensitive form of apparatus was devised later 

 and is shown in Fig. 66. 



Fio. 66. (From J. Physiol., Vol. XXV., Cambridge University Press.) 



A gauge is introduced so that the temperature before and after the action 

 of the ferricyanide is more easily kept constant. The volume is measured in 

 a gas burette filled with water. 



