THE CHEMISTRY OF THE ANIMAL BODY. 995 



tin, from vegetable proteid (conglutin), and from the pancreatic digestion of 

 fibrin. 1 



ALLOXURIC BODIES AND BASES. 



The alloxuric bodies comprise those containing in combination two radicals, 

 one of attoxan, OC < -^-p _ QQ > CO, the other of urea. The skeletal struc- 

 ture of all alloxuric bodies may be written thus : 



N C 



\ 



N C 



N 



C 



Alloxan. Urea. 



These bodies fall into three groups, that of hypoxanthin, of xanthin, and of 

 uric acid. Bodies belonging to the first two groups are called alloxuric bases, 

 or more commonly xanthin bases, or nuclein bases, because they are derived 

 from nuclein. The strong family analogy of the three groups is shown by 

 the following reactions results of heating with hydrochloric acid in sealed 

 tubes at 180 to 200 : 2 



C 5 H 4 N 4 + 7H 2 = 3NH 3 + C 2 H 5 NO 2 + CO 2 + 2CH 2 O 2 . 



HypoxanthiH. Glycocoll. Formic acid. 



C 5 H 4 N 4 O 2 + 6H 3 = 3NH 3 + C 2 H 6 NO 2 + 2CO 2 + CH 2 O 2 . 



Xanthin. 



C 5 H 4 N 4 3 + 5H 2 = 3NH 3 + C 2 H 5 NO 2 + 3CO 2 . 



Uric acid. 



Reference to the formulae below will show that the molecules of CO 2 given 

 off correspond to the number of CO radicals in the alloxuric body, while the 

 molecules of formic acid correspond to the number of CH groups. 



(a) HYPOXANTHIN BASES. 



-\TTT C* TT 



JN.tl (^ 1 



/ II 



Hypoxanthin, or Sarcin, HC C NHv 



^ > CO. This is found in 



N- C=N / 



small amounts in the tissues and fluids of the body and in the urine. The 

 action of water or dilute acids on nuclein yields hypoxanthin. 3 



C H 



/ II 



Adenin, or Imidosarcin, HC C NHv ' 



^ >CNH. This is found 



N C=N / 



1 For literature on these diamido- fatty acids see Klebs : Zeitschrift fur physiologische Chemie, 

 1895, Bd. 19, p. 301. 



2 Kriiger: Ibid., 1894, Bd. 18, p. 463. 3 Kossel : Ibid., 1881, Bd. 5, p. 268. 



