NON-DISSOCIABLE INORGANIC RADICAL 171 



Similarly, solutions of the serum-globulinates of the alkalies 

 and alkaline earths may be obtained which are neutral to litmus 

 and which nevertheless conduct electricity, the passage of a 

 direct current through these solutions being accompanied by 

 transport of the protein to the anode (10). 



Only one conclusion is left open to us, therefore, namely, that 

 the salts which proteins form with inorganic acids and bases do 

 not dissociate at the point of union of the inorganic radical with 

 the protein, but elsewhere, within the 'protein molecule itself, 

 yielding, not an inorganic and a protein ion, but two or more 

 protein ions, in one or more of which the inorganic radical is 

 bound up in a non-dissociable form.* 



On examining the details of the behavior of the protein salts, 

 as electrolytes, we are speedily compelled, by inference, to reach 

 precisely the same conclusion. 



In the first place, the conductivity of solutions of certain 

 protein salts, for example potassium caseinate, is not at all affected 

 by the presence, in the solution, of an excess of the ions of the 

 inorganic radical. This fact is very clearly shown by the fol- 

 lowing experiments (27). 



Two and a half grams of pure casein were dissolved in solu- 

 tions containing varying amounts of KOH of which, in each 

 instance, so much was neutralized by 0.1 AT HCl as to leave the 

 equivalent of 25 cc. of 0.1 iV KOH unneutralized by the acid. 

 These solutions were then each diluted to 250 cc, so that the final 

 solutions consisted of 1 per cent casein dissolved in 0.01 N KOH 

 plus varying amounts of KCl. The conductivities (= x) of these 

 solutions (at 30 degrees) were then determined and also the 

 conductivities (= Xi) of solutions similarly made up without the 

 introduction of casein. The conductivity of the original solu- 

 tion, before the introduction of casein, is the sum of two quanti- 

 ties, i.e., the conductivity of 0.01 KOH + the conductivity of 

 the KCl; that of the solution of the caseinate is the sum of three 

 quantities, i.e., the conductivity of the unneutralized KOH and 

 the conductivity of the KCl + the conductivity of the caseinate. 

 Subtracting the latter from the former, therefore, we obtain 

 Xi — X, which is the conductivity of the 0.01 KOH minus the 

 conductivity of the KOH unneutralized by 1 per cent casein 

 and the conductivity of the caseinate itself; in other words, the 



* Cf . also Chap. IX, 3. 



