338 



PHYSICAL PROPERTIES 



mined differentially, as described) varies very pronouncedly with 

 the nature of the inorganic acids, bases or salts which their solu- 

 tions contain.* 



The following are among Lillie's results, obtained when dilute 

 acids and alkalies were employed as solvents; 



TABLE III 

 1.5 Per Cent Gelatin in Dilute HCl Solutions 



TABLE IV 

 1.5 Per Cent Gelatin in Dilute KOH Solutions 



In Lillie's words, '.'In the presence of either acid or alkali the 

 osmotic pressure of gelatin thus shows a marked increase, which, 

 within the above range of concentrations, exhibits a certain pro- 

 portionality to the quantity of acid or alkali added. For equiva- 

 lent concentrations, acid produces a somewhat greater increase 

 than alkali. The change in osmotic properties is to be attributed 

 to a finer subdivision of the colloid particles and a consequent 

 increase in the surface of intersection between colloid particles and 



* In this connection it is of interest to note that von Wittich (131), von 

 Regeczy (91), Oker-Blom (76) and others have shown that proteins diffuse 

 more rapidly into sodium chloride solutions than they do into distilled water. 

 Cf. also Dabrovsky (23). 



