JACQUES LOEB 627 



p.D. as are expressed in Tables I and II. This fact has already been 

 discussed, but it may be necessary to return to it in a later publication. 



SUMMARY AND CONCLUSIONS. 



1. When solutions of KCl, NaCl, or LiCl are separated from water 

 without salt by a collodion-gelatin membrane and when the pH of 

 both salt solution and water are on the acid side of the isoelectric point 

 of gelatin, water diffuses from the side of pure water into the salt 

 solution at a rate increasing inversely with the radius of the cations. 



2. The adsorption theory would lead us to assume that this influence 

 of the cations is due to an increase of the p.d. between the liquid and 

 the membrane inside the pores of the gelatin film of the membrane, 

 but direct measurements of this p.d. contradict such an assumption, 

 since they show that the influence of the three salts on this p.d. is 

 identical at pH 3.0. 



3. It is found, however, that the p.d. across the membrane is af- 

 fected in a similar way by the three cations as is the transport of water 

 through the membrane. 



4. This P.D. across the membrane varies inversely as the relative 

 mobility of the three cations which suggests that the influence of the 

 three cations on the diffusion of liquid through the membrane is partly 

 if not essentially due to a diffusion potential. 



