JACQUES LOEB 



109 



and molecules diminishes the viscosity but increases the osmotic 

 pressure of the gelatin solution. 



As far as the quantitative relations are concerned, the difference in 

 viscosity (Fig. 8) is more striking than the difference in osmotic 

 pressure (Fig. 7). The osmotic phenomena are a more complicated 

 function of the change caused by the transformation of larger aggre- 

 gates into simple ions, inasmuch as there exists a Dorman equilibrium 

 not only between the gelatin solution and the outside watery solution 



3.5 



o 3.0 



t 



^ 2.5 



03 

 O 

 o 



B 2.0 

 > 



1.5 



LO 

 pH 1.8 2.0 2.2 2.4 26 2.8 3.0 3.2 3.4 36 38 4.0 42 44 4.6 



Fig. 8. Showing that the influence of previous heating on the viscosity of 0.5 

 per cent solutions of gelatin chloride is the reverse of the influence of the previous 

 heating on osmotic pressure (Fig. 7), 



but also between each solid particle of gelatin and the true gelatin 

 solution surrounding it. 



It was expected that when we put a 1 per cent solution of gelatin 

 of, e.g., pH 3.5, which had been kept for 1 hour at 45° and cooled to 

 20° into a 1 per cent solution of an identical gelatin chloride solution 

 of pH 3.5, which had not been heated to 45° before being brought to 

 20°C., water would diffuse from the latter into the former solution. 

 This experiment was carried out with a positive result. 



