HEMOGLOBIN, CARBON MONOXIDE AND OXYGEN 173 



with oxygen and with CO as independent of one another, were it not 

 for the fact that (according to Douglas, Haldane and Haldane) the 

 paradox actually is the expression of the experimental facts. 



Fig. 56, which is a portion of Fig. 7, page 292, of their paper, shows 

 the percentage saturation of the blood with CO. Each Hne represents 

 a certain pressure of CO which for that line remains constant. That 

 pressure would, if there were no oxygen present, saturate the blood 

 to the degree indicated at the intersection of the hne in question 



(^ 



2 4 6 8 10 12 



Pressure of oxygen in percentage of an atmosphere 

 Fig. 56. 



14 



with the ordinate. The abscissa represents the amount of oxygen 

 present. On the curves a httle oxygen increases the quantities of 

 carboxyhsemoglobin present. If, and when, we are able to get a 

 dissociation curve for the equihbrium 



CO + Hb ^i^ HbCO 



(and for the corresponding reaction for oxygen), which is a hyperbola, 

 it will be interesting to see whether this curious property will dis- 

 appear as in theory it should. 



REFERENCES 



(1) Hartbidge and Roughton. Communication to Physiol. Soc. May 1925. 



(2) Douglas, Haldane, J. B. S. and Haldane, J. S. Journ. Physiol, xliv. 



275. 1913. 



(3) Hartbidge. Journ. Physiol, xliv. 23. 1913. 



(4) Haldane and Lobbain Smith. Journ. Physiol, xxn. 231. 1897. 



(5) Kbogh. Published later in Skand. Arch. f. Physiol, xxm. 217. 1910. 



(6) Hill, A. V. Journ. Biol. Chem. is. 359. 1922. 



