SALTS OF ALBUMIN AND ACIDS 



Pauli and Hirschfeld found for a i per cent, solution of the 

 purest serum albumin the value 1-66 x io~ 2 N HC1. This 

 i per cent albumin gave, in a solution of hydrochloric acid of 

 1-66 X io- 2 N strength, a hydrolysis of 187 per cent. 



The proportionality between optimum combination with acid 

 and content of protein is also shown in an experiment of Pauli 

 and Hirschfeld on glutin (see Fig. 16). In a solution which 

 contains i per cent, glutin in acid of concentration 1-5 X io~ 2 

 N HC1, (the maximum quantity combined at that concentration 

 of the protein) , the hydrolysis is 25 per cent. We have now every 



evidence for the view, as opposed to that developed by Robert- 







Table 35- 



son, that albumin reacts as a poly acid base. We know from the 

 electrometric measurements which have been quoted and which 

 are typical, that the anion of the added acid gives a dissociated 

 salt, and we must conclude, on the other hand, from the extent 

 of the combination with acid, that several molecules of acid 

 react with one molecule of albumin. For, as the maximum acid 

 combined in i per cent, (i.e., io gm. per litre) of albumin is 1-66 

 X io- 2 N HCl, so for i gm. per litre the acid concentration 

 would be 1-66 x io- 3 N ; and hence, if it is supposed that only 

 one molecule of acid combines with each molecule of albumin, the 

 molecular weight of the latter works out at less than 600. If, 

 however, the albumin reacts as a polyacid base, forming salts 

 with polyvalent ions, for which there is manifold proof, then 

 the behaviour on hydrolytic dissociation becomes intelligible. 



