THEORIES OF COLLOIDAL BEHAVIOR 



117 



as ordinates over the pH as abscissae. By deducting the values for 

 the specific conductivity of the pure aqueous solution of an acid 

 from the values for the total specific conductivity of the gelatin- 

 acid solution of the same pH the curve for the specific conduc- 

 tivity of the gelatin-acid salt for that pH is obtained. 1 



Figure 38 shows that the curves representing the percentage 

 of ionized gelatin in gelatin chloride resemble the combination 



2.0 22 2A 26 2> 3.0 32 3.4 3.6 3.8 4.0 42 4.4 4.6 



FIG. 38. Curves for the specific conductivity of 2A per cent solutions of 

 gelatin chloride, sulphate, and oxalate, showing the entirely different character of 

 these curves from that of the osmotic pressure curves in Figs. 14 and 15. 



curves in Fig. 8, since in both cases there is a gradual rise in the 

 concentration of ionizable protein at a pH below that of the 

 isoelectric point, but no maximum followed by a drop at pH 3.4 or 

 3.0. But otherwise the curves for combination and for con- 

 ductivity differ; the curve representing the percentage of ionized 

 gelatin is almost the same for gelatin chloride and gelatin sulphate, 

 while for gelatin oxalate the curve is a little lower. If we attempt 

 1 LOEB, J., J. Gen. Physiol, vol. 3, p. 247, 1920-21. 



