236 ELECTROCHEMISTRY 



are the diamino radicals (hexone bases) which are contained in 



the protein molecule. As we shall see in the succeeding section 



of this chapter, the neutralization of bases by the proteins is 



analogously accomplished, at any rate for the greater part, by 



the dicarboxylic radicals which they contain; only the evidence 



which we have so far discussed does not reveal this fact because 



salts of the type 



H OH 



++ \/ 

 ,COK <^N- 



R^ ++ + 



H OH 



do not appear to exist, but only salts of the type 



H OH 



++ \ / 

 ,COK <^N- 



r: ++ + 



H OH 



in which the ratio of the valencies of the cation to the number 

 of equivalents of base included in the molecule of the protein 

 salt is 2; the same as it would be for a salt formed by the open- 

 ing up of a single — COH.N— bond. 



The results obtained with solutions of ovomucoid in dilute 

 acids are complicated by the possible presence of free ovomucoid 

 which is itself ionized and therefore contributes to the conduc- 

 tivity of these solutions. It is evident, however (Cf. Tables XXI 

 and XXII), that the conductivity of a solution of ovomucoid 

 sulphate is practically identical with that of a solution of ovo- 

 mucoid chloride containing the same equivalent concentration 

 (45 X 10~^ equivalents per gram) of neutralized HCl. Hence it 

 follows that in the formation of these salts each equivalent of 

 a dibasic acid must give rise to the same number of equivalents 

 of protein salt that an equivalent of a monobasic acid produces. 

 This conclusion also applies to the salts which the protamin, 

 salmin, forms with acids (19). 



2. The Depression of the Freezing-point of Water which is 

 Caused by Dissolved Protein Salts, and the Stoichiometry of 



