SALTS OF ALBUMIN AND ACIDS 



position. The albumoses certainly give salts with acids which 

 are much less hydrated, as can be seen by the much smaller 

 rise in viscosity, although in this case also continued addition 

 of acid gives rise to a maximum value for the viscosity.* It 

 is only the ionic condition of the albumin and not the existing 

 free H* ions which is important in the digestive action of 

 pepsin on dissolved natural and uncoagulated albumin. In 

 the same way the quantity of acid albumin formed by the 

 action of pepsin passes through a maximum corresponding to 

 the ionisation, when increasing quantities of acid are added. 

 The following experiments by J. Christiansen show this effect. 



Table 38. 



1-3 per cent. Mutton Albumin -f O'oi per cent. Pepsin 



+ HC1. 



Finally, Christiansen has found that ionised albumin pos- 

 sesses the practically important property of being strongly 

 adsorbed by filter paper, particularly in the case of the positive 

 protein ions formed on combination with acids. This adsorp- 

 tion also passes through a maximum corresponding to the 

 ionisation. 



Some observations on the acid-albumin recently made by 

 M. Adolf and E. Speigel f must be mentioned here. The de- 

 natured protein they employed, although insoluble in water, is 



* Unpublished research of Pauli and P. Dukes. (See Table 40.) 

 t Biochem. Zeitsch., 1920, 104, 175. 



