RESPIRATION. 



593 



we expose blood-serum to an atmosphere of oxygen it will absorb no 

 more oxygen than water under the same conditions of pressure, and the 

 amount so absorbed will be far less than that which is capable of being 



absorbed by the blood. The absorption, then, of oxygen by the blood 

 is not due to its plasma. If, however, a solution be prepared of haemo- 

 globin, or the coloring matter which forms 90 per cent, of the dried red 

 corpuscles, and it be exposed to oxygen, it will be found capable of 



