SALTS OF ALBUMIN AND ACIDS 



81 



Experience shows that albumin mixed with acid at low con- 

 centration (up to 0-05 N), if it is not warmed above room 

 temperature and not kept for more than a few days, can be 

 reed from the acid by dialysis without any change in its 

 >riginal properties.* On the basis of what we know of albumin 

 salts it can be stated without a doubt that here the dialysis 

 operates by hydrolytic elimination of the acid at the bounding 

 membrane and subsequent exosmosis of the acid. This experi- 

 ence can, moreover, be expressed and confirmed experimentally 

 by saying that the curve of acid combination (Table 18, Fig. 10) 

 for decreasing acid concentration coincides point for point with 

 that obtained for increasing concentrations of acid. This 

 indicates a homodrome reversible change of state. Let us now 

 consider rather more closely the work of Pauli and Hirschfeld 

 (loc. cit., p. 68) as shown in Table 33 and Fig. 19. 



Table 33 (Fig. 19). 

 Horse-serum Albumin (1*26 per cent.)* 



The 1-26 per cent, serum albumin employed is capable of 

 combining with a maximum quantity of 2-1 X io- 2 N acid 

 per litre. This limiting value, however, only occurs in a con- 

 siderable excess of acid (0-05 N). If, now, 2-1 X io- 2 N acid is 

 added to albumin, instead of AC, only AB (Fig. 19) represents 

 the combined acid so that the degree of hydrolysis, that is, the 

 fraction of the total concentration which is free, is BC/AC. In 



* Such an albumin is called natural or genuine ; whereas one of which 

 the properties (e.g., solubility) have been altered by irreversible trans- 

 formation without complete decomposition is termed denatured. 



