THE DECOMPOSITION PRODUCTS OE PROTEIDS. 75 



Pyridine (C 5 H 5 N 5 ), Picoline (C C H 7 N), Lutidine 

 (C 7 H 9 N), and Collidine (C 8 H„N). 



(xi.) Pyrrol. Of feebly basic properties. 



Perhaps the most interesting of these are the pyridine 

 group and pyrrol ; the former because they have been 

 shown to take a part in the molecular formation of many 

 vegetable alkaloids, e.g., piperidine, cinchonine, etc. As 

 an example which will show us the manner in which the 

 bodies described as decomposition products of proteids 

 by acids and alkalies could become converted by dis- 

 tillation into bodies of closed rings, such as the last two 

 mentioned classes, I will take the conversion by heat of 

 glutaminic acid into pyrrol. At 190 dry glutaminic 



COOH COOH 



/ / 



CH 2 -CH.NH, CPL-CH CH : CH 



I " \ I \ 



CR.-COOH NH I NH 



CH 2 -CO CH : CH 



glutaminic acid. pyroglutaminic acid. pyrrol. 



acid is converted into pyroglutaminic acid, and at a higher 

 temperature this in its turn becomes converted into pyrrol. 1 



5. Decompositions occurring by ferment action. First 

 among these we have the earlier stages of hydration of the 

 proteid, viz., the proteoses and peptones ; but in addition 

 to these it has been shown that the action of trypsin may 

 extend further. The other substances known to be pro- 

 duced may be classified into : — 



(i.) Bases. Lysine and lysatinine have been shown 

 by Hedin, 2 working under Drechsel, to occur among these. 



Hirschler 3 obtained evidence of the production of am- 

 monia, a result confirmed by Stadelmann 4 under conditions 

 precluding the possibility of putrefaction. 



1 Ber. der deutsch. chem. Gesell., xv., 1222. 



2 Du Bois' Archiv, p. 273, 1891. 



■' Zeitschr. f. physiol. Chem., vol. x., p. 302, 1880. 

 4 Zeit. f. Biologie, vol. xxiv., p. 261, 1888. 



