SKATOXYL-SULPHURIC ACID. 695 



glucuronic acid (SCHMIEDEBERG). Such an acid has been found in the 

 urine of animals after the administration of the sodium-salt of o-nitro- 

 phenylpropiolic acid (G. HOPPE-SEYLER). PORCHER and HERVIEUX l 

 have obtained indoxyl sulphuric acid in dogs and asses under similar 

 conditions. 



Free indigo, and in fact indirubin as well as indigotin, occur in rare cases in 

 the undecomposed urine. GROBER and WANG 2 have recently observed such cases. 



C.CH 3 



Skatoxyl-sulphuric Acid, C 9 H 9 XSO 4 , C 6 H 4 ^\C.O.SO 2 .OH, has not 



NH 



been positively prepared as a constituent of normal urine, but OTTO 

 has once prepared its alkali salt from diabetic urine. Perhaps skatoxyi 

 occurs in normal urine as a conjugated glucuronate (MAYER and NEU- 

 BERG 3 ), and it is believed that the urine contains a skatol-chromogen 

 from which red and reddish-violet coloring-matters are obtained by 

 decomposition with strong acids and an oxidizing agent. 



Skatoxyl-sulphuric acid originates, if it exists in the urine, from 

 skatol, which is formed by putrefaction in the intestine, and which is then 

 conjugated with sulphuric acid after oxidation into skatoxyi. That 

 skatol introduced into the body passes partly as an ethereal-sulphuric 

 acid into the urine has been shown by BRIEGER. Indol and skatol act 

 differently, at least in dogs, indol producing a considerable amount 

 of ethereal-sulphuric acid, while skatol gives only a small quantity (MES- 

 TER 4 ). Reports on this subject are at variance. 



The conditions for the formation of indol and skatol by the putrefaction of 

 proteins in the intestine are decidedly different, according to HERTER, as skatol 

 is produced by other putrefaction bacteria than indol. For example, bacillus coli 

 communis produces indol, but only traces of skatol, while skatol is formed by 

 certain anaerobic putrefactive bacteria. An important intermediary step in the 

 formation of skatol is the indol acetic acid (skatol carboxylic acid, according to 

 SALKOWSKI) and this can also pass into the urine and is the chromogen of the 

 urorosein, according to HERTER. S 



The potassium salt of skatoxyi -sulphuric acid is crystalline; it dis- 

 solves in water, but with difficulty in alcohol. A watery solution becomes 

 deep violet with ferric chloride. The solution becomes red with con- 

 centrated hydrochloric acid with the separation of a red precipitate. 

 This precipitate (skatol red) is, after washing with water, insoluble in 



1 Schmiedeberg, Arch. f. exp. Path. u. Pharm., 14; G. Hoppe-Seyler, Zeitschr. f. 

 physiol. Chem., 7 and 8; Porcher and Hervieux, Journ. de Physiol., 7. 



2 Grober, Mtinch. med. Wochenschr., 1904; Wang, Salkowski's Festschrift, 1904. 



3 Otto, Pfluger's Arch., 33; Mayer and Neuberg, Zeitschr. f. physiol. Chem., 29. 



4 Brieger, Ber. d. deutsch. chem. Gesellsch., 12, and Zeitschr. f. physiol. Chem., 

 4, 414; Mester, ibid., 12. 



5 Journ. of biol. Chem., 4. 



