78 



Scientific Proceedings (52). 



Haldane and Barcroft with laked rabbit saturated with oxygen 

 at the prevailing partial pressure in the air. Total hemoglobin 

 concentration determined spectrophotometrically, using the con- 

 stants of oxyhemoglobin from ox blood. Here again for a 3-fold 

 variation in concentration 0 2 /Hb. is constant. The apparent 

 slight excess over I mol. O2 to I mol. Hb. is probably due to a 

 slight difference in the optical constants of oxyhemoglobin from 

 rabbit blood and oxyhemoglobin from ox blood. 



The fourth and last series was obtained from measurements of 

 the light absorption of laked ox blood and oxyhemoglobin from 

 ox blood at the wave-lengths 577, 579 fin (double line, mercury 

 arc) and 546 juju. Log (Zi/7/) is the log of the ratio of initial 

 and final intensities in the solution at 577, 579 nn, log 

 the log of the corresponding ratio at 546 n/x. Between the quotient 

 of the logs of these ratios and the concentration of hemoglobin 

 (oxygen-free) in the presence of oxyhemoglobin there exists the 

 following relation : 



log 77 (01 ~ <*i)x + Oil 



log T> (02 — 0:2)* + oc 2 

 in which x = relative concentration of hemoglobin, on, ot 2 , ft, 02 



log jp 



constants which can be determined experimentally. If j- 



log -r> 

 12 



remains constant on dilution then x must be constant. That is if 

 log p 



remains constant on dilution at constant 0 2 pressure the 



log y-> 



relative composition of the solution (oxyhemoglobin and hemo- 

 globin) also remains constant. 



We will now apply these results to the existing views on the 

 nature of the absorption of oxygen by hemoglobin. Several con- 

 siderations not embodied in the table will also be of aid in selecting 

 the most probable formula. 



The Bohr formula falls out for the following reasons: 



