URINE. 2/9 



ETHEREAL SULPHURIC ACIDS. 



The most important of the ethereal sulphuric acids found in the 

 urine are phenol-sulphuric acid, p-cresol-sulphuric acid, indoxyl- 

 sulphuric acid and skatoxyl-sulphuric acid. Pyrocatechin-sulphuric 

 acid also occurs in traces in human urine. The total output of 

 ethereal sulphuric acid varies from 0.09 to 0.62 gram for 24 hours. 

 In health the ratio of ethereal sulphuric acid to inorganic sulphuric 

 acid is about i : io. These ethereal sulphuric acids originate in part 

 from the phenol, cresol, indole and skatole formed in the putrefac- 

 tion of protein material in the intestine. The phenol passes to the 

 liver where it is conjugated to form phenyl potassium sulphate and 

 appears in this form in the urine whereas the indole and skatole 

 undergo a preliminary oxidation to form indoxyl and skatoxyl 

 respectively before their elimination. 



It has generally been considered that each of the ethereal sul- 

 phuric acids was formed principally in the putrefaction of protein 

 material in the intestine and that therefore a determination of the 

 total ethereal sulphuric acid content of the urine was an index of the 

 extent to which these putrefactive processes were proceeding within 

 the organism. Recently, however, Folin has conducted a series of 

 experiments which seem to show that the ethereal sulphuric acid con- 

 tent of the urine does not afford an index of the extent of intestinal 

 putrefaction, since these bodies arise only in part from putrefactive 

 processes. He claims that the ethereal sulphuric acid excretion 

 represents a form of sulphur metabolism which is more in evidence 

 upon a diet containing a very small amount of protein or upon a 

 diet containing absolutely no protein. The ethereal sulphuric 

 acid content of the urine diminishes as the total sulphur 

 content diminishes but the percentage decrease is much less. There- 

 fore when considered from the standpoint of the total sulphuric 

 acid content the ethereal sulphuric acid content is not diminished 

 but is increased, although the total sulphuric acid content is dimin- 

 ished. Folin's experiments also seem to show that the indoxyl 

 sulphuric acid (indoxyl potassium sulphate or indican) content of 

 the urine does not originate to any degree from the metabolism 

 of protein material but that it arises in great part from intestinal 

 putrefaction and that the excretion of indoxyl sulphuric acid may 

 alone be taken as a rough index of the extent of putrefactive proc- 

 esses within the intestine. Indoxyl sulphuric acid, 



