IN ISO-ELECTRIC REACTION 



45 



It is certain from this work by Pauli and Samec that when 

 strong acids are added to albumin or glutin these proteins show 

 a number of properties which agree with those found by means 

 of buffer solutions at the iso-electric point. The hydrion con- 

 centration at which this effect occurs is, however, far below 

 that determined by acetic acid acetate mixtures for the iso- 

 electric point. This is accompanied by a relatively large 

 quantity of acid entering into combination for i per cent. 

 albumin or glutin it is of the order of io~ 4 N/i. 



The equation of electrical neutrality in which, as is well 

 known, the sum of positive ionic charges is equal to the sum of 

 negative ionic charges in any given mixture of electrolytes, for 

 the point of charge in precipitation by alcohol and in viscosity 

 found in the above investigations is as follows : 



CGI- + CQH -- h Q\- 



or, inserting the values in powers of ten which have been 

 determined : 



io-* (CIO + io-' (OHO + C A - = C A + -f io- 6 (H-). 



In any case, at this point the concentration of negatively 

 charged albumin must be much reduced compared with the 

 positively charged portion. In fact, in electrophoresis experi- 

 ments in this region, migration to the cathode is exclusively 

 observed (Table 15). With strong acids, therefore, the maxi- 

 mum of neutral particles does not coincide with the point of iso- 

 electric migration. 



Apparently, with strong acids, in lower concentration than 

 the P H of the iso-electric point found by buffer solutions, a 

 regular combination with the albumin occurs. This com- 

 bination increases with further addition of acid with formation 

 of new positive albumin ions. 



One can conclude theoretically that in this case also a parti- 

 cular acid concentration must exist at which the originally 

 anodic migration changes to a cathodic migration, giving rise 



chlorion remains completely dissociated not only at such concentrations, 

 but even with much higher content of HC1 in a 5 per cent, albumin 

 solution. In the proof appended of the extinction of the positive 

 albumin ions, the chief emphasis must be laid on the observed migration 

 to the positive pole rather than on the excess of chlorine ions present. 



