INFLUENCE OF THE CONCENTRATION OF ELECTRO- 

 LYTES ON THE ELECTRIFICATION AND THE 

 RATE OF DIFFUSION OF WATER THROUGH 

 COLLODION MEMBRANES. 



By JACQUES LOEB. 

 (From the Laboratories of The Rockefeller Institute for Medical Research.) 



(Received for publication, September 6, 1919.) 



/. Influence of the Concentration of Electrolytes upon the Rate of 



Difusion of Positively Charged Particles of Water 



through Collodion Membranes. 



When we fill a collodion flask, as described in a preceding publi- 

 cation,^ with a solution of a non-electrolyte, e.g. cane sugar, grape 

 sugar, or glycerol, and dip the flask into a beaker containing distilled 

 water, the level of the liquid in the flask will rise, as is to be expected 

 on the basis of the gas pressure theory of osmosis. When we close 

 the opening of the collodion flask with a rubber stopper, perforated 

 by a glass tube with a bore of about 2 mm. in diameter serving as 

 manometer, the rate of diffusion of water into the solution can be 

 conveniently followed. Since at the same time sugar will diffuse out 

 of the flask into the surrounding distilled water, the rise of the col- 

 umn of hquid in the manometer will cease after some time {e.g. after 

 about 70 minutes at 24°C.) and will be followed by a fall in the level 

 of the Hquid, until finally the solutions inside and outside the collo- 

 dion flask become identical. It is therefore necessary to consider 

 only the initial rise of liquid in the manometer as an indicator for the 

 attractive action of the solution upon water, and in all the figures 

 given in this paper the readings were made 20 minutes after com- 

 mencement of the experiment. At the beginning of the experiment 

 the level in the manometer was usually about 30 mm. above that of 

 the distilled water in the beaker in order to discover possible cases of 

 negative osmosis. All collodion flasks had practically the same sur- 



1 Loeb, J., /. Gen. Physiol., 1918-19, i, 717. 



173 



