ORGANIC POISONS 249 



toxicatetl by being converted into corresponding salts, but only after 

 a preliminary oxidation into indoxyl and skatoxyl, according to the 

 following reaction: 



A host of other aromatic organic substances are similarly combined 

 with sulphuric acid,-^ with or without preliminary oxidation, includ- 

 ing all substances resembling phenol or which through oxidation are 

 changed into phenols, such as cresol, thymol, anilin, naphthalin, pyro- 

 gallol, and tannin. By this means a poisonous substance is converted 

 into a relatively harmless one, which is readily soluble and rapidlj^ 

 eliminated. 



2. Glycuronic acid occupies the same position as sulphuric acid, com- 

 bining particularly with naphthol, thymol, camphor, chloral hydrate, 

 and butyl chloral. Sometimes a substance may appear in the urine 

 combined in part with sulphuric, in part with glycuronic acid, show- 

 ing the similarity of their function. Apparently when there is not 

 sufficient sulphuric acid in the body to combine with all the poison, 

 the excess unites with glycuronic acid,-* although combination between 

 glycuronic acid and the aromatic substance begins to occur before all 

 the sulphuric acid is exhausted.-'' Glycuronic acid represents merely 

 a first step in the oxidation of glucose, as follows : 



OHC-(CHOH),-CH,OH + 0, = OHC- (CHOH),-COOH + H.O. 

 (glucose) (glycuronic acid) 



This oxidation occurs after the aldehyde group of the glucose has 

 been combined by some other substance ; hence the aldehyde group 

 escapes oxidation, although ordinarily more easily oxidized than the 

 alcohol group. 



Just as with the addition of sulphuric acid, oxidation may be a 

 preliminary step to the addition of glycuronic acid : e. g., naphthalin 

 is oxidized into a-naphthol, before uniting to glycuronic acid, as fol- 

 lows : 



23 See Hammarsten's Text-book (fourth American ed. ), p. 542. 



24 See Austin and Barron, Boston ]Med. and Surg. Jour.,. 190,5 (152), 260. 

 Wohlgemuth has observed a case in which all the sulphuric acid of the urine was 

 in organic combination (Berl. klin. Woch.. lOOG (43). 508). 



25 See Salkowski, Zeit. physiol. Chem.. 1004 (42), 230. 



