DILUTION 221 



From this mode of deriving the formula it is clear that the 

 total equivalent concentration of the electrolyte may be expressed 

 in terms of the electric conductivity of its solution as the sum 

 of two factors, the first, directly proportional to the conductiv- 

 ity, being the equivalent concentration of the dissociated part 

 of the electrolyte and the second, directly proportional to an 

 exponent of the electrical conductivity (in this instance 2), be- 

 ing the undissociated part of the electrolyte. 



The salts which the proteins form with inorganic bases and 

 acids obey the Ostwald dilution-law for a binary electrolyte (7) 

 (8) (10) (12) (15) (16) (17) (19), that is, the relationship between 

 the equivalent concentration of the protein salt and the con- 

 ductivity (in reciprocal ohms per cubic centimetre) is that indi- 

 cated by formula (i) . It is to be observed, however, that without 

 additional assumptions we do not know what is the equivalent 

 concentration of a protein salt. If we assume, however, that m, 

 the equivalent concentration of the base or acid which is neu- 

 tralized by the protein, bears a constant proportion to the true 

 equivalent concentration of the protein salt, then (i) becomes 

 _ 1.037 X 10-^ 1.075 X 10-4 ^ 

 ^ ~ p(u-hv) ^ "^ Kp (u -\-vy^' ^''^ 



in which m is now the known equivalent concentration of the 

 base or acid which is bound by the protein and p is the number 

 of equivalents of protein salt to which each equivalent of neutralized 

 acid or base gives rise. This equation may be written: 



m = Ax -{- Bx^, (iii) 



in which A and B are constants, respectively equal to 

 r.037 X 10- 2 1.075 X lO-'t 



p{u -\- v) Kp ill + v)2 



The fact that the dependence of the conductivity of solutions 

 of protein salts upon their dilution obeys the formula (iii), there- 

 fore, shows that for a given salt p is constant; in other words, 

 for a given combination of acid or base with protein, containing 

 a given proportion of the acid or base, the number of equivalents 

 of protein salt to which one equivalent of neutralized acid or 

 base gives rise is independent of the dilution. 



The validity of equation (iii) as applied to solutions of protein 

 salts may be gathered from the accompanying tables. In each 

 case the most probable values of the constants A and B are com- 



