366 PHYSIOLOGICAL CHEMISTRY. 



Indoxyl-sulphuric acid, C^NSO^ or C 8 H 6 N.O.S0 2 .OH, also 

 called URIKE IXDICAN, formerly called UROXANTHIN (HELLER), 

 occurs as alkali-salt in the urine. This compound is the mother- 

 substance of a great part of the indigo of the urine. The quantity 

 of indigo which can be separated from the urine is considered as a 

 measure of the quantity of indoxyl-sulphuric acid (and indoxyl- 

 glycuronic acid) contained in the urine. This amount, according 

 to JAFFE, for man is 5-20 milligrammes per 24 hours. Horse's 

 urine contains about 25 times as much indigo-forming substance as 

 human urine. 



Indoxyl-sulphuric acid is derived, as above mentioned (page 21 6), 

 from indol, which is first oxidized in the body into indoxyl and 

 then is coupled with sulphuric acid. After subcutaneous injection 

 of indol the elimination of indican is considerably increased 

 (JAFFE, BAUMANN and BRIEGER). It is also increased by the 

 introduction of orthonitrophenylpropiolic acid in the organism of 

 animals (G-. HOPPE-SEYLER). Indol is formed by the putrefaction 

 of proteids, and it is therefore easy to understand why the quantity 

 of indoxyl-sulphuric acid is greater with a meat than with a vege- 

 table diet. The putrefaction of secretions rich in albumin in the 

 intestine explains also the occurrence of indican in the urine 

 during starvation. Gelatine, on the contrary, does not increase the 

 elimination of indican. An abnormally-increased elimination of 

 indican occurs in such diseases as obstruct the small intestine, 

 causing an increased putrefaction, thus producing an abundant 

 formation of indol. Such an increased elimination of indican 

 occurs on tying the small intestine of a dog, but not the large 

 intestine (JAFFE). 



The simple obstruction of the human colon does not increase 

 the indican in the urine. The obstruction of the large intestine 

 may, when it causes a considerable disturbance in the motion of 

 the contents of the upper ileum, produce an increased elimination 

 of indican. Like the putrefaction in the intestine, the putrefaction 

 of proteids in other organs and tissues of the body may cause an 

 increase in the indican of the urine. 



An increased elimination of indican has been observed in many 

 diseases, such as in ileus, cholera, acute general peritonitis, abscess, 

 and carcinoma of the stomach, intestinal catarrh, multiple lym- 



