176 



I. B. WILSON 



100 



20 



i 



8 



pH 



10 



Fig. 1 



In each case the positively charged member of the pair is the better inhibitor. 

 The resuhs are shown in Table I. 



What one would like to do, I suppose, is to see how this compares to a simple 

 equation for the Coulombic potential energy of two charges, Za and Zb , 

 separated by a distance, R. 



U = 



-Za Zb 



The dielectric constant involves some difficulties, but Schwartzenbach has 

 indicated a way of handling that problem (Pressman and Pauling have used 

 this method) by selecting an effective dielectric constant in accordance with 

 empirical observations relating D to R. 



TABLE I 

 The effect of positive electrical charge on the potency of inhibition 



N-Methylnicotinamide-nicotinamide 



Eserine cation-eserine 



Dimethylethanolammonium ion-isoamylalcohol. . . 



if (corrected 

 for salt) 



5.8 

 5.4 

 5.0 



