JACQUES LOEB 



99 



ment about twice as high as that of the 1 per cent solution of Ba 

 gelatinate of about the same pH. During the first hour the relative 

 rise of level in the solutions is also approximately as 1:2. Fig. 4 

 gives the curves for Na gelatinate and Ca gelatinate. The curve 

 for Na gelatinate in Fig. 4 is identical with the curve for NH4 gelati- 

 nate in Fig. 3 and the curve for Ca gelatinate in Fig. 4 is identical 

 with the curve for Ba gelatinate in Fig. 3. The curves for Li and 

 K gelatinate were identical with the curves for NH4 and Na gelatinate 

 in Figs. 3 and 4. Such results are always obtainable when both the 



e 



£ 



00 



P-. 

 CL 



O 



• r-l 

 -t-» 

 O 



e 



to 

 O 



260 

 240 

 220 

 200 

 160 

 IGO 

 140 

 120 

 100 



80 



60 



40 



20 



1 2 3 4 5 6 7 6 9 10 11 la 



Time in hours 



Fig. 4. Curves of osmotic pressure of 1 per cent solutions of Na and Ca gelati- 

 nate (pH = 8.8). Pressure in mm. of column of gelatin solution. 



concentration and the pH of the solutions are identical. We there- 

 fore reach the conclusion that the different metal ions influence the 

 osmotic pressure of gelatin solutions in the same sense as they influ- 

 ence the rate of migration of water into the solution. This supports 

 the idea that the electrification of the water particles plays a role in 

 the magnitude of the osmotic pressure as obtained by the use of 

 semipermeable membranes. 



