424 INDOL. SKATOL. [BOOK II. 



4. Indol is dissolved in very little benzol, and about three times 

 its weight of crystallised picric acid is then added. The liquid being 

 cautiously heated, enough benzol is added to dissolve the whole. On 

 cooling, the liquid is converted into a magma of red crystals, owing 

 to the union of equal molecules of indol and picric acid. This 

 compound, which presents the appearance of long, red, shining crystals 

 is soluble with difficulty in cold benzol or petroleum ether, but it 

 can be easily recrystallised from its solution in the former. In order 

 to separate indol from its picric acid compound, the latter is decom- 

 posed with ammonia, and the solution is shaken with petroleum 

 ether, which readily dissolves the liberated indol. On evaporating 

 the solution, indol in the form of fine crystals is left behind 1 . 



Fate and A part, probably the chief part, of the iudol formed 



transforma- in the intestines is excreted in the faeces A part is, 

 tions of indol however, especially if constipation or obstruction of the 

 nomy 6 bowels exist, absorbed, oxidised, and excreted in the 



urine as the potassium salt of indoxyl-sulphuric acid or 

 indican (see p. 169). From the amount of the latter substance, we 

 can form a judgment as to the extent of the putrefactive decompo- 

 sition of proteids in the alimentary canal. The matter will be again 

 considered in discussing the constituents of the urine. 



2. Skatol\ C 9 H 9 N or 



Skatol or /3-methyl-indol, was separated, in Nencki's laboratory by 

 Brieger 3 , from the faeces; Nencki 4 afterwards obtained it from the 

 products of pancreatic putrefaction. 



Methods of Nencki allowed 2330 grms. of fresh pancreas and 

 preparation. 500 g rms> of meat> free from fat and well m i uce d, 



mixed with eight litres of water, to decompose during 5 months, the 

 temperature varying during this period between 3'5 C. and 27*5 C. 

 At this temperature, he found only skatol, and no indol amongst the 

 products. 



In order to separate the skatol, he added an excess of acetic acid 

 and distilled. The distillate was acidulated with hydrochloric acid 

 and treated with picric acid, which precipitates skatol, in the form of 



gekommenen Nitroprussidsalzreactionen,' Krukenberg's Untersuch. Heft 2, pp. 117 136, 

 see p. 134, Jena, 1888. 



1 Hoppe-Seyler, Handbuch d. phys. u. path. Chem. Anal. 6te Aufl. Berlin, 1893, 

 p. 163. 



2 From CTK&P, gen. 0vcar6s, dung. 



3 L. Brieger, 'Ueber die fliichtigen Bestandtheile der menschlichen Excremente' 

 (aus d. Lab. von Prof. Nencki in Bern), Ber. d. deutsch. chem. Gesellsch. Vol. x. (1877), 

 pp. 10271032. 



4 M. Nencki, ' Vortheilhafte Darstellung des Skatols,' Centralblatt f. d. med. 

 Wissenschaft. No. 47. 



