JACQUES LOEB AND ROBERT F. LOEB 



193 



The rate of swelling is a function apparently not only of the Donnan 

 equilibrium, but also of the force of cohesion between the particles. 

 Procter and Wilson* have suggested that the rapid increase of swelling 

 of solid gelatin with a rise in temperature is due to a corresponding 



Svv'-elling di\d 

 solution of casein 

 in different acic3s 

 at24"'C.in24hours 



iOOO 500 200 100 50 



N M n U ]Vi 9M 



20 10 4 2 ^^^ ^^^ 



Concentration of acids 



Fig. 2. Swelling of the same granules after 24 hours. Where the swelling 

 exceeds a certain limit, between 5 and 6 in our scale, the particles are dissolved, 

 thus showing that swelling is of importance in the mechanism of solution of casein 

 chloride. 



diminution of cohesion between the molecules of gelatin \vith rising 

 temperature. The influence of the anion of gelatin-acid salts on the 

 cohesion of the particles of a solid gel is apparently much less than 

 the influence of the anion on the cohesion of casein particles. The 



