JACQUES LOEB 



675 



ments on electrical endosmose.^ We will first describe experiments 

 in which the membrane is negatively and the watery phase positively 

 charged. 



We have shown in a previous paper that anions accelerate and 

 cations depress the rate of diffusion of water through negatively 

 charged membranes. ^ Fig. 1 shows the relative influence of the 

 anions of three potassium salts, KCl, KBr, and KI on the rate of 

 diffusion of water through collodion membranes. The ordinates 



UMIIMNriNriMIliTvr 

 ^ 1024 512 256 128 64 32 16 8 4 2 ' 



Concentration o[ salt solution 



Fig. 1. The rate of diffusion of water through a negatively charged membrane 

 (from the side of pure water to solution) and the density of the charge of the latter 

 are increased by monovalent, monatomic anions in the order I > Br > CI. 

 Solutions almost neutral (pH about 6.0). 



indicate the rise of hquid in the manometer in 20 minutes; the abscissas 

 indicate the concentration of the solution. The salt solutions as 

 well as the pure water separated from the solution by the collodion 

 membrane were almost neutral, having a hydrogen ion concentration 

 of about IQ-s N. It is obvious that the accelerating influence of 



^ Loeb, J., /. Gen. Physiol, 1919-20, ii, 577. 

 2 Loeb, J., /. Gen. Physiol, 1919-20, ii, 173. 



