42 THE GENERAL CHARACTERS OF THE PROTEINS 



hydrolysis of the hydrochloride (the protein having no conductivity), 

 and 55*66 x io~ 7 represents the value when no dissociation takes 

 place, then using the ordinary formula when x represents the pro- 

 portion hydrolysed 



314* + (i - *)55'66 = 100-5 



whence ;r = 0*174, from which it was calculated that 17*4 per cent. 

 of protein hydrochloride was hydrolysed when a 0*05 N solution of 

 hydrochloric acid solution was neutralised with egg-proteins. 



These experiments of Sjoqvist were carried out with the whole 

 of the proteins of egg-white, and therefore probably with a mixture. 

 Some of the calculations, furthermore, are approximations. They 

 have, however, been described in some detail, as they demonstrate in 

 a clear manner the salt formation when proteins are treated with 

 acids ; they also indicate the methods for determination of the 

 hydrolysis of such salts. 



A similar set of conductivity determinations with the proteins of 

 horse serum is due to Mellanby. 



A. II. Electric Potential Method. 



This method has been employed by Bugarsky and Liebermann. 

 According to the theory of Nernst, the electro-motive force of a 

 galvanic element constituted according to the following scheme- 

 Platinum laden with H 2 | Acid j Base | Platinum laden with H 2 



depends on the concentration of the hydrogen ions in the acid and 

 base solutions. 



The addition of a protein to either the acid or base would in 

 the event of combination and salt formation alter the concentration of 

 the various ions in solution. 



The electro-motive force of such an element as the above can, 

 according to the Nernst theoiy of electrolytic solution pressure, be 

 expressed by the following equation : 



RT C H d\ 



TT = p- nat log 

 E *H 



where R is the ordinary gas constant, T the absolute temperature, 

 E the quantity of electricity transported by I gram equivalent of 

 an electrolyte, CH the concentration of the hydrogen ions in the acid, 

 and XK the concentration of hydrogen ions in the base. If the electro- 

 motive power be expressed in volts, the quantity of electricity in cou- 

 lombs, and the electrical energy I volt-coulomb = 10,000,000 ergs, and 

 the experiments be all carried out at a constant temperature (25 C.)> 



R T 

 then _- is a constant = 0*0256. 



EO 



If now the Brigg logarithms be substituted for the natural loga- 

 rithms, 



* = 0-0590 Iog 10 ^-? 

 H 



The hydrogen ions in the acid depend on the dissociation of the 

 acid in the concentration employed in the experiments. 



In the base solution (sodium hydroxide was used in the experi- 



