JACQUES LOEB AND ROBERT F. LOEB 



203 



are highly soluble. 0.8 gm. of powdered gelatin of pH of about 3.3 

 dissolves very rapidly in 100 cc. HCl of the same pH at 35''C. The 

 addition of NaCl or CaCl2 no longer increases the solubility, except 

 when the concentration of CaCl2 becomes greater than m/16. Na2S04 



150 

 140 

 130 



c 



S 



c 



.x-l 



Q 



120 



110 

 100 



90 

 60 

 70 

 60 

 50 



CQ 40 



30 



20 



10 







^ 1024 512 256 r28 64 32 16 8 4 2 ^^^ "^'^ 



Concentration of salts 



Fig. 5. Influence of salts on tLine required to dissolve 0.8 gm. of powdered 

 gelatin chloride of pH 3.3 at 35°C. 



abruptly diminishes the solubility at a concentration above m/4 and 

 NaCl above a concentration of 1 m (Fig. 5). 



Fig. 6 shows the influence of the three salts on the solution time of 

 Na gclatinatc of pH 10.5. NazSOj diminishes the solubility abruptly 



