50 



THEORY OF COLLOIDAL BEHAVIOR 



In Fig. 7 the abscissae are the pH while the ordinates are the 

 number of cubic centimeters of 0.1 N HC1, H 2 SO 4 , H 2 oxalate, 



pHlfi 2.0 2.2 2.4 2.6 ZQ 3.0 3.2 3.4 3.6 3.8 4.0 42 44 46 



FIG. 7. Titration curve for 1 per cent solution of originally isoelectric gelatin, 

 proving the stoichiometrical character of combination of acids with gelatin 

 (see legend under Fig. 6). 



and H 3 PO 4 contained in 100 c.c. solution of originally isoelectric 

 gelatin to the same pH, 



