PHENOL. 201 



Tests. An aqueous solution of phenol when treated with a few 

 drops of a solution of the sesquichlorideof iron assumes an amethyst 

 color, which becomes especially apparent on further dilution with 

 water if much phenol is present. 



With bromine-water a crystalline precipitate of tribromophenol is 

 obtained. 



With Millon's reagent a red color develops, which, however, is 

 common to other bodies of this series as well (see page 34). 



Isolation (see page 206). 



In addition to phenol, indol, skatol, and skatol-carbonic acid, as 

 also the two hydroxylated benzol-derivatives of tyrosin, viz., para- 

 oxy-phenyl-propionic acid (hydro paracumaric acid) and para-oxy- 

 phenyl-acetic acid, we further meet with two non-hydroxylated 

 aromatic acids, which are homologous with benzoic acid, viz., phenyl- 

 propionic or hydrocinnamic acid and phenyl-acetic acid. Accord- 

 ing to Salkowski, these may develop directly from the albuminous 

 molecule, but may also result from tyrosin (see page 97). 



The non-nitrogenous aromatic acids are in part eliminated in the 

 feces. To some extent, however, they are also absorbed. The 

 hydroxylated acids are then eliminated in the urine either as such, 

 or, like phenol, indol, and skatoxyl, in combination with sulphuric 

 acid, while the non-hydroxylated acids combine with glycocoll, and 

 are eliminated as hippuric acid and phenaceturic acid, as already 

 described (page 97). 



As regards the fate of the small amounts of leucin, asparaginic 

 acid, and glutaminic acid which are also formed during the process 

 of albuminous putrefaction, it seems that they are usually absorbed, 

 and are then further decomposed within the body of the animal. To 

 a slight extent, however, this decomposition also takes place within 

 the large intestine, and we accordingly meet with small amounts 

 of succinic acid, glutaric acid, capronic acid, valerianic acid, butyric 

 acid, and acetic acid. The sulphur of the albuminous molecule is 

 usually set free in the form of hydrogen sulphide, but traces of 

 methyl-mercaptan are also frequently observed, and still further 

 contribute to the offensive odor of the feces. Whether these sulphur 

 bodies result from decomposition of the tryptophan, is not known. 



Of the gases which are constantly present in the contents of the 

 large intestine, methane further deserves especial mention. It is to 

 a great extent, no doubt, referable to the peculiar form of fermenta- 

 tion to which the celluloses are subject. But in part at least it prob- 

 ably also results from the decomposition of the fatty acids and of 

 cholin. 



Ptomains are normally not found in the intestinal contents, but 

 may be encountered under certain pathological conditions. In Asiatic 

 cholera and in cases of cystinuria putrescin and cadaverin have thus 

 been isolated, and in other diseases, no doubt, they also occur. 



The methods which are employed for the purpose of isolating the 



