170 PHYSICAL CHEMISTRY 



serum to indicators, may increase the oxidation of erythrocytes, 

 whereas NaOH is ineffective. Since NH 3 penetrates so much 

 more easily than fixed alkalis, this indicates that NH 3 affects 

 oxidation in the interior, or else the action is on the plasma 

 membrane. 



Warburg found that anesthetics reduced the oxidation of 

 erythrocytes according to their anesthetic power. He illustrated 

 it by the following model (1914) : Blood charcoal causes the 

 oxidation of oxalic acid adsorbed to its surface to C0 2 and H 2 0. 

 This charcoal, even after washing with HC1, contains iron which 

 may be the real catalyzer. The catalytic action of the charcoal 

 varies with its power of adsorbing oxalic acid. If an anesthetic 

 is added to the solution of oxalic acid the oxidation is reduced. 

 The more easily the anesthetic is adsorbed the greater is its 

 inhibitory action. The explanation of this action is that the 

 anesthetic is more strongly adsorbed than the oxalic acid, which 

 it displaces from the surface of the charcoal. 



McClendon and Mitchell (1912) showed that those solutions 

 that were most effective in increasing the permeability and caus- 

 ing the segmentation of unfertilized sea urchin eggs, are also 

 most effective in increasing the oxidation. Warburg (1910 a) 

 combats the idea that the segmentation is the cause of the oxida- 

 tion. He finds that phenyl urethane may stop the segmentation 

 without reducing the oxidation to a significant degree. But the 

 segmentation and increased oxidation might be due to increased 

 permeability without the two running parallel. Let us suppose 

 that oxidation is proportional to permeability. A too great in- 

 crease in permeability will prevent segmentation, but it might 

 greatly increase oxidation. 



Whereas Warburg is forced to admit some connection between 

 the plasma membrane and oxidation, he claims this does not hold 

 true for the unfertilized sea urchin egg, whose oxidation is not 

 decreased by grinding with sand. But this fact is capable of 

 another interpretation. It may be a mere coincidence that the 

 absorption of oxygen by the intact and the ground egg is the 

 same, since the production of C0 2 ceases on grinding. The first 

 impact of the sand may cause the eggs to begin development, 

 since they may be caused to segment by shaking in a vial. In 

 this condition they are the same as fertilized eggs, with enor- 



