THE DECOMPOSITION PRODUCTS OF PROTEIDS. 73 



by reduction valerianic acid CH 3 (CH 2 ) 3 COOH is produced. 

 All these bodies have been identified by Drechsel, and he 

 moreover shows that the process can be carried out to the 

 end, when all the carbon appears as carbonic anhydride, the 

 hydrogen as water. 



On similar treatment of an amido-acid a similar series is 

 observed, the nitrogen being ultimately found as ammonium 

 carbonate. 



Further the same process will convert ammonium 

 carbonate into urea. 1 



This series of changes will thus help us to understand 

 the formation of several terms in the homologous series 

 isolated by Schiitzenberger, and the contrast of but few of 

 the terms of the series isolated after treating proteids with 

 strong acids. 



Drechsel obtained lysine and lysatinine from casein, 

 but working under his direction several of his pupils have 

 discovered them among the cleavage products of other pro- 

 teids. Fischer' 2 obtained them from gelatin. Siegfried 

 obtained them from conglutin 3 and from reticulin. 4 Sieg- 

 fried working with conglutin also obtained a body of for- 

 mula (C 8 H l6 N 2 4 ) n of sweet taste, and answering to one of 

 the bodies described by Schiitzenberger as a glucoprotein. 



3. The action of oxidising agents. Treatment with 

 nitric acid has yielded oxalic, fumade, and saccharic acids. 

 By its early action a yellow insoluble substance, xantho- 

 proteic acid, is first produced, but this gradually dissolves, 

 and finally there is produced para-oxybenzoic and oxy- 

 benzoic acids. These latter are probably due to the oxida- 

 tion of tyrosine. 5 



Oxidation with manganese dioxide and sulphuric acid, 

 or with potassium bichromate and sulphuric acid, has 

 yielded — 



1 Drechsel, Journ. f. Prak. Chemie (2), vol. 22, p. 476. 



2 Inaugural Dissert., Leipzig, 1S90; and Du Bois' Archiv, p. 265, 1891. 



3 Ber. d. deut. ckem. Gesell., vol. xxiv., p. 418. 



4 Ueber die chemischen Eigenschaften des reticulirten Gewebes (Habi/ita- 

 tionschrift), Leipzig, Dec, 1892. 



5 See Baumann, Ber. d. deutsch. C/ie/n. Gesellschaft, 12, 1453. 



