998 AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



Uric acid oxidized with permanganate of potash is converted into allantoin, C 4 H 6 N 4 3 , 

 a substance which is found in the allantoic fluid, and in the urine of pregnant women and 

 of newborn children. 



If uric acid be carefully evaporated with nitric acid on a small white porcelain cover, 

 a reddish residue remains, which moistened with ammonia gives a brilliant purple color 

 due to the formation of murexid, C 8 H 4 (NH 4 )N 5 O 6 ; subsequent addition of alkali gives 

 a red coloration. This is known as the murexid test and is very delicate. 



Carnin, or Dimethyl Uric Acid. The formula is unknown. Carnin is 

 found in tissue, and has been detected in extracts of meat and in the urine. 

 A synthetic dimethyl uric acid of the following formula, 



NCH S = 



OC C NH V 



\ II >CO, 



NCH 3 C NIT 



when fused with oxalic acid is converted into theophyllin. 1 This is the only 

 transformation between the uric-acid group and the xanthin bases known in the 

 laboratory. 



THE ALLOXURIC ACIDS AND BASES IN THE BODY To the definitely 

 determined facts belong (1) that these substances when fed are generally con- 

 verted into urea ; (2) that some nucleins under proper chemical treatment 

 break up as follows : 



Nuclein. 



Proteid. Nucleic acid. 



Phosphoric acid. Adenin. 



Guanin. 

 Xanthin. 

 Hypoxanthin. 



(3) that these last named substances have been obtained from no proteid other 

 than nuclein (see Nuclein). The idea that the alloxuric bodies in mammals were 

 metabolic products of nuclein, the uric acid being derived from oxidation of the 

 bases, was especially emphasized by Horbaczewski. 2 His statement that uric 

 acid and the bases are increased in the urine after feeding nuclein has been con- 

 firmed. 3 The increase of alloxuric bodies in the urine in leucocythsemia has long 

 been known, and is now explained by the increased nuclein-metabolisrn following 

 the destruction of the white blood-corpuscles. An interesting investigation of a 

 case of leucocythsemia * has shown that ingested theobromin is burned as in the 

 normal person ; the explanation is offered that the alloxuric bodies produced 



1 Fischer and Acht: Berichte <kr Berliner Academic, 1895, p. 259. 



2 Sitzungsberichte der Wiener Akademie der Wissenschaften, 1891, Bd. C. Abth. iii. p. 13. 



s Weintraud: Verhandlung der Berliner physiologische Gesellschaft, Archiv filr Physiologic, 

 1895, p. 382. 



* Boudzynski and Gottlieb : Archiv filr exper. Pathologic und Pharmakologie, 1895, Bd. 36, 

 p. 127. 



