252 LECTURE XII. 



cially, for instance, by the administration of phenol. If this be introduced 

 into the animal organism, it appears in the urine as potassium phenyl- 

 sulphate. 1 We assume it to be formed as follows: 



HO . SO 3 K = C 6 H 5 . O . SO 3 K + H 2 O 



Phenol Potassium phenylsulphate 



We will add that not only substances like phenol are eliminated in this 

 way, but in place of phenol we may find: the cresols, CH 3 . CeH 4 OH; 

 thymol, C3H 7 (CH 3 ) Cells . OH, also the dihydroxy-benzenes, C6H 4 (OH 4 ) 2 ; 

 methylquinol, CH 3 . . C 6 H 4 OH; orcinol, CH 3 . C 6 H 3 (OH) 2 ; pyrogallol, 

 C 6 H 3 (OH) 3 ; tribromphenol, Br 3 C 6 H 2 OH; o-nitrophenol, NO 3 .C 6 H 4 .OH; 

 p-amidophenol, NH 2 . CeH 4 . OH; protocatechuic acid, COOH.C6H 3 (OH) 2 ; 

 tannin, salicylamide, m- and p-hydroxybenzoic acids. 



Before discussing the sulphuric acid esters which normally occur in 

 urine, we will mention the fact that in addition to the above compounds 

 produced by the artificial introduction of aromatic compounds, substitution 

 products of the phenols and hydroxyl derivatives of other cyclic com- 

 pounds may also appear in urine conjugated with sulphuric acid. Such 

 an example is hydroxyquinolin sulphate, which, to some extent at least, 

 appears in urine as an acid ester of sulphuric acid. Here also it is inter- 

 esting to note that in the organism substances are prepared for combina- 

 tion which of themselves are incapable of reacting together. For example, 

 benzene is first oxidized to phenol, and then united with sulphuric acid. 

 We shall soon see that indole and skatole are also first oxidized to indoxyl 

 and skatoxyl, and then further made to combine: 



NH : C 8 H 6 + O = HN : C 8 H 5 OH 



Indol Indoxyl 



HN . C 8 H 5 . OH + OH . S0 3 K = HN : C 8 H 5 . O .SO 3 K+ H 2 O 



Indoxyl Pot. indoxylsulphate 



It is also interesting that substances, themselves capable of combination, 

 are likewise oxidized. This part of the phenol is oxidized to quinol and 

 appears then as quinol sulphuric acid: 



C 6 H 5 . OH + O = HO . C 6 H 4 . OH 



Phenol Quinol 



HO . C 6 H 4 . OH + HO . SO 3 K = HO . C 6 H 4 . O . S0 3 K + H 2 O 



Potassium quinol sulphate 



These reactions indicate that the formation of sulphuric acid esters is 

 dependent on the presence of aromatic compounds, whether these are 



1 E. Baumann and E. Herter: Ber. 9, 1747 (1876); 1, 244 (1877-78). 



2 C. Brahm: Z. physiol. Chem. 28, 439 (1899). 



