92 HEMOGLOBIN 



1 c.c. of the solution at the temperature of the experiment and at 

 760 mm. pressure, the concentration of oxygen at any other pressure 



^ is ^ ,^— r . The experiment, then, will consist in exposing portions of 



haemoglobin solution to various atmospheres containing known pres- 

 sures of oxygen and subsequently determining the amounts of oxy- 

 and reduced haemoglobin in each sample after an equilibrium has 

 been established between the haemoglobin and the atmosphere. 

 Suppose we have five closed vessels each containing a small quantity 

 of haemoglobin solution and also at the same time oxygen at the 

 following pressures, namely 0, 10, 20, 40 and 100 mm. of mercury 

 (Fig. 19). After the fluids had been shaken up thoroughly at 38° C. 

 the concentrations of oxygen would be 



(1) (2) (3) (4) (6) 



"XtIo i^tIo ^OtIo ''"tTo ioOtSo""- 



That is: 



-00029 -00058 -00116 -0029 c.c. 



of oxygen in each c.c. of fluid. 



Now we must find out what proportion of the haemoglobin is 

 oxy haemoglobin, and the following are figures such as we should obtain : 



Vessel (1) (2) (3) (4) (5) 



0% 55% 72% 84:% 92% 



The best idea we can get of the relation of these numbers to one 

 another is to place the following picture before our eyes. Supposing 

 the haemoglobin in each case to be in a cylindrical tube and that the 

 oxy- and reduced haemoglobin could be separated from one another, 

 the former being red and sinking to the bottom and the latter purple 

 and rising to the top, we should obtain five cylinders as shown in 

 Fig. 20 corresponding to the oxygen pressures in the five tonometers. 



We are impelled to ask whether any definite relationship exists 

 between these quantities of oxyhaemoglobin and the oxygen pressures 

 to which they correspond. In doing so we must bear in mind that 

 we shall shortly be face to face with a very serious position, for the 

 very relationship which we are about to investigate is defined by 

 the law of mass action itself, and should the relation as found not 

 agree with that as prescribed, our theory must be abandoned and 

 some other explanation of the properties of haemoglobin must be 



