JACQUES LOEB 



683 



mum is, however, not identical. For p.d. it varies between 3.6 and 

 4.0, while for osmotic pressure it lies near 3.6.' With a further fall 

 in pH both sets of curves show approximately the same steep drop. 



425 

 400 

 375 

 350 

 325 

 300 

 E75 

 250 

 225 

 200 

 175 

 150 

 125 

 100 

 75 



U 



w 

 to 



(X 



e 



w 

 o 



50 



25 





 pH 2.0 2.2 24 2.6 Z& 3.0 3.2 34 36 38 4.0 42 44 4.6 



Fig. 5. Influence of pH and valency of anion on osmotic pressure of solutions 

 of different gelatin-acid salts. 



The second point of similarity is the influence of valency. The 

 curves for p.d. (Fig. 6) are practically the same for gelatin chloride 

 and gelatin phosphate, while the curve for p.d. is considerably lower 

 in the case of gelatin sulfate. 



' It may be stated incidentally that the maximum for the viscosity of gelatin 

 solution also lies at a different pH, namely 3.0, from the maximum for osmotic 

 pressure, which lies at pH 3.6. 



