THE CHEMISTRY OF THE AX IMA I BODY. 569 



derived from the products of proteid putrefaction in the intestines. It is 

 admitted that neither fats nor carbohydrates play any part in their formation. 



Benzol, C 6 H 6 . — This body if fed is absorbed and afterward converted into oxybenzol 

 or phenol, with subsequent behavior similar to phenol. 



Phenol (Carbolic Acid, Oxybenzol, Phenyl-hydroxide), C 6 H 5 OH. — 

 This is an aromatic alcohol. A 5 per cent, solution precipitates proteid, and a 

 much weaker solution produces irritation of the tissues, and especially those 

 of the kidney, where its excretion takes place. It is strange that a strong 

 antiseptic like phenol should be a normal product of proteid putrefaction. 

 Phenol is obtainable from tyrosin, by processes of cleavage and oxidation (see 

 Tyrosin), and in the intestinal canal is probably derived from tyrosin. A 

 small amount of the phenol ordinarily absorbed is converted by the organism 

 into pyrocatechin, a dioxybenzol. These two substances are found in normal 

 urine in ethereal combination with sulphuric acid, C 6 H 5 O.SO,,.OH (or as an 

 alkaline ethereal sulphate). This synthesis, accomplished by the union of the 

 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-dioxybenzol. For its forma- 

 tion see under Phenol. 



Hydroquinone, C 6 H 4 (OH) 2 . — Para-dioxy benzol. 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/ | . 



p-Cresol, 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. 



Benzoic Acid, C 6 H 6 COOH. — Salts of this acid and analogous bodies 

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

 considerable amount of hippuric <i<-i<l, COOH.CH 2 .NH.CO.C 6 H 8 , the com- 

 bination of benzoic acid and glycocoll (sec Glycocoll, p. 537). On (reding 

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

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

 phenyl-propionic add, sutler the oxidation of the side chain in the ho.lv, and 



1 Drechsel : Journal fin- praktUehe Chemie, Bd. 29, ]>. 229 : abstr. Jahresberichi uber Thiercfu 



1884, S. 77. 



