boeLectric polal 



Region of Gelalui-SO^ 

 and of Gelatln-Cl 



Point of Neutrality 

 RegLon ot Gelatln-Na 



nClconcenlralion ^ 3j ^ 



pn db 3.6 5.9 4.1 4.6 5.1 5.6 6.4 



Fig. 2. Na2S04-HCl curves. Isoelectric point and minimum again near 

 pH = 4.7. Values for osmotic pressure, swelling, and alcohol number on right of 

 isoelectric point, where gelatin exists as sodium gelatinate, higher than on left, 

 where it exists as mixture of gelatin sulfate and gelatin chloride. The curves for 

 osmotic pressure, sweUing, and alcohol number are not parallel to the curve for 

 conductivity. 



47 



