THE CHEMISTRY OF THE ANIMAL BODY. 1011 



phenol and sulphuric acid with loss of water, has been obtained by electrolysis, 

 using alternating electric currents. 1 If phenol be administered in more than 

 a very small amount, hydroquinone likewise appears in the urine, paired like 

 the others with sulphuric acid, and should the phenol administered exceed at 

 any time the available sulphate, it forms to a certain extent a synthesis with 

 glycuronic acid, and so combined appears in the urine. 



Phenol gives with Millon's reagent (mercuric nitrate in nitric acid with some nitrous 

 acid) a brilliant red coloration. This is given by all bodies having an hydroxyl group on the 

 benzol ring, of which substance tyrosin may be mentioned as an example. It is likewise 

 given by proteid, slowly in the cold, more rapidly on warming, and this fact together 

 with the cleavage putrefactive products has given foundation to the belief that the oxy- 

 benzol ring exists preformed in the proteid molecule. 



Pyrocatechin, C 6 H 4 (OH) 2 . This is ortho-dioxy benzol. For its forma- 

 tion see under Phenol. 



Hydroquinone, C 6 H 4 (OH) 2 . Para-dioxybenzol. Found in the urine 

 especially in cases of carbolic-acid poisoning (see Phenol). If such urine be 

 shaken in the air, it is turned black, owing to the oxidation of hydroquinone 



/ 



to quinone, C 6 H,/ | . 



X 



p-Creaol, C 6 H 4 .OH.CH 3 . This is a product of intestinal putrefaction, and is 

 derived from tyrosin (which see). It is found in the urine as an ethereal sulphate. 



Benzole Acid, C 6 H 5 COOH. Salts of this acid and analogous bodies 

 are found especially in plants. In the urine of herbivora therefore is found a 

 considerable amount of hippuric acid, COOH.CH 2 .NH.CO.C 6 H 5 , the com- 

 bination of benzoic acid and glycocoll (see Glycocoll, p. 981). On feeding 

 phenyl-acetic acid, C 6 H 5 CH 2 COOH, phenaceturic acid, COOH.CH 2 .NH.- 

 CO.CH 2 .C 6 H 5 , appears in the urine, while the higher benzyl acids, such as 

 phenyl-propionic acid, suffer the oxidation of the side chain in the body, and 

 ordinary hippuric acid is formed. After eating apple-parings and other vege- 

 table substances, hippuric acid is found in human urine. It is further stated 

 that phenyl-acetic acid and phenyl-propionic acids are normal products of 

 proteid putrefaction, though in very small quantities ; hippuric acid and phen- 

 aceturic acid must therefore be constantly present in traces in human urine. 

 Hippuric acid is split into its constituents by hydrolysis through the action of 

 the Micrococcus urece. 



p-Oxyphenyl-acetic Acid, C 6 H 4 .OH.CH 2 COOH. This is a product of 

 the intestinal putrefaction of proteid and of tyrosin (which see). It occurs 

 in the urine either paired with sulphuric acid or as an alkaline salt of oxyphenyl- 

 acetic acid. 2 



jo-Hydrocumaric Acid, C 6 H 4 .OH.C 2 H 4 COOH. This second oxy- acid is 

 likewise derived from proteid and tyrosin (which see) putrefaction. Its occur- 

 rence in the urine is similar to the above oxy- acid. 



Tyrosin, Amido-hydrocumaric Acid, >-Oxyphenyl-amido-propionic 



1 Drechsel : Journal filr praktisvhe Chemie, Bd. 29, p. 229 ; abstr. Jahresbericht iiber Thierchemie, 

 1884, p. 77. 2 Baumann : Zeitschrift fur physiologische Chemie, 1886, Bd. 10, p. 125. 



