FREEZING- AND BOILING-POINTS 



333 



tion is, however, very questionable, since it depends upon the 

 assumption that the proteins in blood are non-electrolytes. While 

 it is probable as Hardy's results indicate (Cf. Chap. VII, section 6), 

 that the proteins in normal blood are non-ionic, the possibility 

 must not be lost sight of that they may participate, as isolated 

 water soluble proteins frequently do, in the conduction of a cur- 

 rent through their solutions (Cf. Chaps. VIII and X). 



The majority of the above estimates were not carried out upon 

 pure proteins. Robertson and Burnett (106), however, have 

 investigated the cryoscopic depression due to dissolved caseinates 

 of the alkalies and alkaline earths, employing pure casein. The 

 following were the results obtained. 



TABLE I 



Caseinates containing 50X10"^ equivalents of base per gram 

 (Experimental error of determination ± . 0025 degrees) 



