564 COLLOIDAL BEHAVIOR OF PROTEINS 



tion of originally isoelectric gelatin. It was found that the curves for 

 the values for p.d. of these four gelatin salts are parallel to the curves 

 of their osmotic pressure and that the values for pH inside minus pH 

 outside multiplied by 58 give approximately the millivolts of these p.d. 

 In this preliminary note only the influence of the concentration 

 of the hydrogen ions on the p.d. has been taken into consideration. 

 In the fuller paper, which is to follow, the possible influence of the 

 concentration of the anions on this quantity will have to be discussed. 



The writer wishes to express his indebtedness to his technical as- 

 sistants, Mr. M. Kunitz and Mr. N. Wuest, who have carried out the 

 measurements in these experiments. 



