218 CHEMISTRY OF THE PROTEIDS CHAP. 



He found that 1 gram of edestin is equivalent to 212 milligrams HC1 

 if there be a large excess of hydrochloric acid, while it combines with 

 only 26 milligrams, i.e. with only 12 per cent of the 212 milligrams, 

 if there is no excess of hydrochloric acid ; 88 per cent of the hydro- 

 chloric acid is liberated by hydrolysis. If one dissolve serum-albumin 

 in one-tenth normal hydrochloric acid, then 1 gramme will bind 0'104 

 milligramme HC1 ; on diluting this solution with an equal bulk of 

 1:10 Ti-HCl, it binds 0*142 gramme; if it be diluted four times with 

 1:10 Ti-HCl it binds 0'204 gramme. By means of another method 

 Sjoqvist found serum-albumin to bind 0*12 to 0'13 gramme. 



Different albumins differ not only in their capacity for binding 

 acids, but give different curves, when these are so constructed as to 

 show that dissociation depends not only on the concentration but also 

 on the excess of the acid. If a weaker acid be taken instead of hydro- 

 chloric acid, then the dissociation becomes even more marked. 



Albumins behave quite analogously when they combine with bases ; 

 Bugarszky and Liebermann * and Spiro and Pemsel 2 have shown that 

 sodium albuminate exhibits marked and varying hydrolysis. 



One essential difference exists, however, between albumins and the 

 simple amino-acids : the albumins are pluri-acid bases and pluri-basic 

 acids. On p. 147 a comparison has already been made between the 

 equivalent weights as determined by Erb, and the minimal molecular 

 weight as calculated from the percentage composition ; egg-albumin must 

 be at least 35-acid and serum-albumin at least 56-acid. According to 

 Sjoqvist egg-albumin is at least 19 -acid. Regarded as acids they 

 appear to be less basic, according to Spiro and Pemsel. According to 

 Laqueur and Sackur 3 casein in its acid capacity is 4 to 6-basic. 



Hydrolytic dissociation produces thus this effect : 1 gram of albumin 

 neutralises according to its own concentration and that of the acid or 

 base with which it comes into contact, and also according to the nature 

 of the acids and bases, quite different amounts of these acids or bases, a 

 phenomenon which for a long time made it very difficult to under- 

 stand what was really taking place. Sjoqvist was the first to speak in 

 clear terms of the chlorides of albumins and to deduce their properties 

 from the laws formulated by Arrhenius. Then Spiro and Pemsel 

 expressed the reaction between albumins, acids and bases, not as a salt- 

 formation but as a process of distribution along physical lines. 

 Cohnheim and Krieger described albumins as pseudo-bases and pseudo- 



1 St. Bugarszky and L. Liebermann, Pftiiger's Arch.f. d. ges. Phys. 72. 51 (1898). 



2 K. Spiro and W. Pemsel, Zeitschr. f. physiol. Chem. 26. 233 (1898). 



3 E. Laqueur and 0. Sackur, Hofmeister's Beitrage, 3. 193 (1902). 



