THE URINE. 363 



the uriue seems to be due to a fermentative decomposition of hippuric acid. 

 Such a decomposition may very easily occur in an alkaline urine or one con- 

 . taming albumin (VAN DE VELDE and STOKVIB). In certain animals pigs 

 and dogs the kidneys, according to SCHMIEDEBERG and MINKOWSKI, contain 

 a special enzyme, SCHMIEDEBERG'S histozym, which splits the hippuric acid 

 with the separation of benzoic acid. 



Ethereal Sulphuric Acids. Phenol, whose mother-substance is 

 considered to be tyrosin, is produced by the putrefaction of albumin 

 in the intestines ; indol and skatol are also produced. The phenol 

 and the two last-mentioned bodies, after they have been oxidized 

 into indoxyl and skatoxyl, pass into the urine as ethereal sulphuric 

 acids after uniting with sulphuric acid. The most important of 

 these ethereal acids are phenol- and cresol-sulpliuric acid which 

 were formerly called phenol-forming substance indoxyl- and 

 skatoxyl-sulplmric acid. To this group belong also the pyrocate- 

 chin-sulphuric acid, which only occurs in very small amounts in 

 human urine, and hydrochinon-sulpUuric acid, which appears in 

 the urine after poisoning with phenol, and perhaps under physio- 

 logical conditions other ethereal acids occur which have not been 

 isolated. The ethereal sulphuric acids of the urine were discovered 

 and specially studied by BATJMANN. The quantity of these acids in 

 the urine is small. The quantity of grouped sulphuric acid per 

 twenty-four hours is on an average 0.25 grm., but varies between 

 0.094 and 0.620 grm. The relationship of the sulphate-sulphuric 

 acid A to the grouped sulphuric acid B in health is on an average 

 as 10 : 1, but varies from 6 : 1 and 15 : 1. After taking phenol, 

 also after increased putrefaction within the organism, this relation- 

 ship may be essentially changed by an increased elimination of 

 ethereal sulphuric acids. The urine of the horse is considerably 

 richer in ethereal sulphuric acids than human urine. 



Phenol- and p-Cresol-sulphuric Acid, C 6 H B .O.S0 2 .OH and 

 C 7 H,.O.S0 2 .OH. These acids are found as alkali salts in human 

 urine, in which also orthocresol has been detected. The quantity 

 of cresol-sulphuric acid is considerably greater than phenol-sul- 

 phuric acid. In the quantitative estimation the phenols set free 

 from the two ethereal acids are determined together as tribrom- 

 phenol. The quantity of phenol which is separated from the 

 ethereal sulphuric acids of the urine amounts to 17-51 milligrammes 

 in the twenty-four hours (MuNK). After a vegetable diet the 



