JACQUES LOEB 



489 



once with 25 cc. of H2O at 20°C. Then the mass was made into a 1 per 

 cent solution and put into collodion bags to determine the osmotic 

 pressure. Each collodion bag was surrounded by a beaker containing 

 400 cc. of distilled water and the temperature was kept constant at 

 24°C. This allowed any excess of alkali left to diffuse out of the bag. 

 The next day the osmotic pressure was measured, the pH of the gela- 



350 



325 



300 



275 



250 



225 



200 



175 



150 



125 



100 



75 



50 



25 







4 



3 



2 



pH 49 5.2 55 58 6.1 6.4 6.7 70 73 7.6 79 8.2 8.5 8.8 9.1 9.4 



NaOH 



Fig. 3. See explanation under Fig. 2, 



tin solution was determined, the solution titrated to determine the 

 quantity of Na or K, etc., in combination with the gelatin, and the 

 conductivity of the solution was measured. 



The results of these measurements are contained in Figs. 2 to 7. 

 The abscissas are the pH, the ordinates the values for conductivity 

 and osmotic pressure for these pH. The reader will notice that the 

 curves representing the influence of Li, Na, K, and NH4 on the osmotic 



