418 



LECTURE XVIII. 



oxygen absorbed, the small amount merely absorbed by the plasma was 

 deducted. These values may be represented graphically by plotting the 

 oxygen pressures as abscissae, and the amount of oxygen absorbed as 

 ordinates. Two such plotted curves representing the curves of oxygen 

 tension, as Bohr called them, are shown below in which the dotted line 

 represents the absorption by the plasma, the other that quantity which 

 is chemically bound. 



In the above table column 4 shows the per cent of chemically combined 

 oxygen, placing arbitrarily that absorbed at 150 millimeters pressure at 

 100 per cent. 



10 20 30 40 50 60 70 80 90 100 110 120 130 140 ISO 



FIG. 3. Absorption of Oxygen at Various Pressures by Horse's Blood at 38. 



These two curves show very clearly the different behavior of the chemi- 

 cally combined oxygen, and that which is nearly absorbed. The amount 

 of the latter increases regularly in proportion to the pressure as it should 



