368 PHYSIOLOGICAL CHEMISTRY. 



Skatoxyl-sulphuric Acid, C 9 H 9 lSrS0 4 or 9 H 8 .N.O.S0 2 .OH. The 



potassium-salt of this acid seems to occur generally in human urine 

 as a chromogen, which yields a red or violet coloring matter on de- 

 composing with strong acids, and an oxidizing reagent. This salt 

 has been prepared by OTTO from diabetic human urine. Little is 

 known of the quantity of this skatolchromogen, to which probably 

 also the skatoxyl-glycuronic acid must be counted, under physiol- 

 ogical and pathological conditions. 



Skatoxyl-sulphuric acid originates from skatol formed by putre- 

 faction in the intestine, which is coupled with sulphuric acid after 

 oxidation into skatoxyl. 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 only gives a small quantity (MESTER). Skatol 

 seems partly to pass into the urine as a skatoxyl-glycuronic acid. 



The potassium-salt of skatoxyl-sulphuric acid is crystalline; it 

 dissolves in water, but with difficulty in alcohol. A watery solution 

 becomes deep violet with ferric chloride, and red with concentrated 

 nitric acid. The salt is decomposed by concentrated hydrochloric 

 acid with the separation of a red precipitate. The nature of this 

 red coloring matter produced by the decomposition of skatoxyl- 

 sulphuric acid is not well known; neither is the relationship exist- 

 ing between this and other red coloring matters in the urine known. 

 On distillation with zinc-dust the skatol coloring matter yields 

 skatol. 



Urines containing skatoxyl are colored dark red to violet by 

 JAFFE'S indican test even after the addition of hydrochloric acid; 

 with nitric acid they are colored cherry-red, and on warming with 

 ferric chloride and hydrochloric acid red. The coloring matter 

 which yields skatol with zinc-dust may be removed from the urine 

 by ether. Urines rich in skatoxyl darken when allowed to stand, 

 and may become reddish, violet, or nearly black. 



SALKOWSKI has shown that the occurrence of skatol-carbonic acid, C 9 H 8 . 

 N.COOH, in normal urine is probable. This is also a putrefaction product. 



Aromatic Oxyacids. In the putrefaction of proteids in the 

 intestine, paraoxyplienyl-acetic acid, C 6 H 4 (OH).CH 2 COOH, and 



