JACQUES LOEB 



101 



When we fill the collodion bags as described with distilled water 

 and put the bags into 1 per cent solutions of different gelatin acid 

 salts of the same pH, giving the water inside the bag an initial pres- 

 sure head of about 125 mm. of H2O, the water will diffuse out more 

 slowly against the gelatin sulfate than against any of the solutions 

 of the other gelatin salts. This is demonstrated by Fig. 5. The 

 abscissae are the time in minutes, the ordinates the level of water in 



5 10 15 20 25 30 35 40 45 50 55 60 Go 7Q 75 



Time in minutes 



Fig. 5. Curves of fall of level of water when diffusing under an initial pressure 

 head of about 120 mm. of H2O against 1 per cent solutions of gelatin sulfate, 

 gelatin citrate, and gelatin nitrate (pH = 3.5). 



the manometer of the collodion flask. The initial pressure head was 

 125 mm. It required about 25 or 30 minutes for the pressure head 

 of distilled water to fall from 120 mm. to about 20 mm. when it 

 diffused into gelatin nitrate and monogelatin citrate, and 60 minutes 

 when the distilled water 'diffused into gelatin sulfate. 



The second method of testing the influence of the anion on the 

 rate of diffusion of water consisted in determining the balancing 



