706 



DONNAN EQUILIBRIUM AND OSMOTIC PRESSURE 



observed values. This or both discrepancies may be due to a con- 

 stant experimental error or they may find their explanation in the 

 influence of one or more factors not taken into consideration in our 

 calculations. 



450 



425 



400 



375 



350 



325 

 h 300 

 TO 275 

 ^250 

 .y 225 

 I 200 

 O 175 



150 



125 



100 

 75 



50 

 25 





 pH 1.6 L8 20 22 2.4 26 28 3.0 3.2 34 36 38 40 4.2 44 4.6 



Fig. 3. Showing agreement and minor discrepancies between the curves of 

 observed and calculated osmotic pressures of 1 per cent gelatin chloride solutions. 



The calculated and observed curves for gelatin phosphate are 

 identical with those for gelatin chloride given in Fig. 3, and we there- 

 fore omit these curves. 



Fig. 4 gives the curves for observed and calculated values for 

 gelatin sulfate. It seemed of interest to calculate the osmotic pres- 



