iv THE HEMI- AND ANTI-GROUPS 151 



peptones, amino-acids and their secondary dissociation-products, while 

 another part remained unchanged and became oxidised. Oxidation 

 by means of nitric acid showed v. Fiirth 1 that only a portion of the 

 albumin becomes nitrated, while the remainder is dissociated. 



The difference between the hemi- and the anti-groups is also of 

 importance for the metabolism of animals, as the readily dissociable 

 albumins, namely, casein and protalbumose, offer more favourable 

 conditions for absorption and transformation than do gelatine and 

 hetero-albumose. 2 



The difference in the readiness with which the two groups become 

 dissociated may be explained in a twofold manner. We may assume, 

 firstly : that one or several nuclei exist in an albumin-molecule, and that 

 these nuclei completely resist the action of trypsin, and that they are 

 only with difficulty attacked by boiling acids, and that attached to these 

 nuclei is a smaller or greater number of other amino-acids, which may 

 be split off readily. The other possibility is the following : An albumin 

 may be built up of a number of co-ordinated peptones and peptids 

 and may dissociate into these groups in the first instance ; subse- 

 quently some of these groups may break up at once under the 

 influence of trypsin and of acids, while others may show greater resist- 

 ing power. The first view, held by Zunz, Goldschmidt, Bernert, v. 

 Fiirth, E. Fischer, and Bergell, is supported by the fact that the 

 different amino-acids appear successively, but this sequence may 

 perhaps only be an apparent one, owing to the slight solubility of 

 tyrosin. The second view has in its favour that the nuclei of Siegfried 

 and E. Fischer differ from one another constitutionally, but further 

 research may show that these differences are only apparent. 



The two views need not necessarily exclude one another, for we 

 may assume with Kossel that each larger albumose-complex possesses 

 its own nucleus. That the second view is the correct one will be 

 proved as soon as an albumin is discovered which does not possess a 

 ' nucleus ' at all, which, therefore, to use Kuhne-Pick's expression, is 

 a pure hemi-albumin, devoid of those dissociation-products which are 

 characteristic of the anti-group. Casein, which seems to be a hemi- 

 albumin because of the absence of glycocoll, is in reality not a 

 hemi-albumin, and the quickness with which the biuret - reaction 

 disappears in the case of protalbumose proves nothing, as a peptid 



1 0. v. Fiirth, JEimvirkung von Salpetersaure auf Eiiveissstoffe, Habilitationsschrift, 

 Strassburg, ]899. 



2 L. Blum, Zeitschr. f. physiol. Chem. 30. 15 (1900) ; 0. Krummacher, Zeitschr. f. 

 Biolog. 42. 242 (1901) ; E. Bendix, Arch. f. (Anat. u.) Physiol, 1900, Suppl. p. 309 ; 

 W. Falta, Verhandl. der naturfarschenden Ges. zu Basel, 15. Heft 2 (1903). 



