36 KozLOWSKi : Primary Synthesis of Proteids 



acid, ammoniac and amidic acids, places them in the nearest vicinity 

 with uric acid, which gives also by hydrolysis carbonic acid, am- 

 moniac acid, glycocol. 



The principal facts to be accounted for with these different 

 hypotheses are the following : 



1. The last product containing nitrogen in the metamorphosis 

 of animals is carbamide or uric acid. 



2. The compounds from which proteids are formed in plants, 

 as will be shown later on, are most probably amides (including 

 amidic acids and their amides, and especially asparagin) and the 



carbohydrates. 



3. The products of decomposition of proteids under the action 



of pure chemical agents. These are in the most part amides 

 which are obtained by the action of bromine,* of barium hydrate 

 under high pressure, f of hydrochloric acid and stannous chloride, | 

 by long boiling with sulphuric acid,§ or acids in greater part from 

 the fatty series, obtained through the action of manganese dioxide 

 and sulphuric acid || as well as chromic acid.^ Besides carbonic 

 acid and oxalic acid are nearly always formed. 



The presence of hippuric acid in the urine of herbivorous ani- 

 mals, the indol and the skatol found in the products of pancreatic 

 digestion (Salkowski), the tyrosin nearly always present in the ani- 

 mal body, lead to the supposition that aromatic groups are also 

 constituents of the proteid-molecule and it even seems that some 

 'of the most characteristic color reactions of these compounds are 



due to them.** 



We shall not pass over in silence the synthesis of colloidal bodies 

 obtained by Grimaux and by Schiitzenberger, which shows a very 



great resemblance to proteids. Grimaux obtained his colloid by 

 melting together asparagic anhydride with carbamide; Schiit- 

 zenberger by the action of epichlorhydrin upon carbamide. 



/ ' 



* Hasiwetz and Habermann, Liebig's Annalen, 159 : 304. 



■f Schiitzenberger, Annales de Chimie et de Physique, V. 16 : 289. 



Jllasiwetz and Ilabcrmann, Lieb. Ann. 169 : 150. 



^ Kreusler, Zcitschrift fiir Cliemie, 1870 : 93. 



Guckelbcrger, Liebig*s Annalen, 64 : 39. 

 \ Ibidem. 

 ■^■^ So the reaction upon krautoprotein, by Millon and Liebermann. See Wiirtz. 



Second supplement au Dictionnaire de Chemie, 1S92. 



