INDOXYL-SULPHUKIC ACID. 729 



The putrefaction of proteins in other organs and tissues besides the 

 intestine may also cause an increase in the indican of the urine. Cer- 

 tain investigators, BLUMENTHAL, ROSENFELD, and LEWIN, claim to 

 have shown that an increased excretion of indican can also be 'brought 

 about without putrefaction by an increased destruction of tissue in starva- 

 tion and also after phlorhizin poisoning; but these statements are vehe- 

 mently opposed by other investigators, such as P. MAYER, SCHOLZ, and 

 ELLINGER, and are improbable. The indol, it seems, is not formed from 

 the tryptophane (indolaminopropionic acid) as intermediary step in the 

 demolition of the proteins in the animal body, but rather from the 

 putrefaction of the tryptophane in the intestine. GENTZEN l has also 

 shown that tryptophane introduced subcutaneously or per os into the 

 body does not lead to an indicanuria, but only when it is exposed to bac- 

 terial decomposition in the large intestine. The reports as to the elimina- 

 tion of indican after oxalic-acid poisoning are conflicting. After poison- 

 ing with oxalic acid HARNACK and v. LEYEN found an increased indican 

 elimination, and MORACZEWSKI believes he has proven a certain par- 

 allelism between the quantity of indican and the quantity of oxalic acid 

 in diabetes. ScHOLZ, 2 on the contrary, obtained no increase in the 

 excretion of indican after oxalic-acid poisoning. 



The excretion of indican is, as above stated, increased by the introduction of 

 indol, but also by indoxyl or indoxyl-carboxylic acid. Indol-carboxylic acid, 

 on the contrary, does not yield indican, but, according to PORCHER and HER- 

 VIEUX, another chromogen. BENEDICENTI has also shown that indigo blue or 

 analogous blue or green pigments are produced only from those derivatives 



CH CH 



of indol which, like n-methyl indol C 6 H 4 <^%CH, a-naphtindol, Ci H 6 /\CH or 



N.CH 3 NH 



CH 2 



tt-methylindolin, C 6 H 4 <. >CH 2 , do not have the hydrogen atoms of the two methine 



N.OH, 



groups substituted by alkyl. From those derivatives in which one or two hydro- 

 gen atoms are substituted by alkyl, such as skatol, a-methyl indol, dimethyl indol, 

 C.CH 3 CH 



C 6 H 4 <(j>C.CH 3 , and bz. 3, p. 2-dimethyl indol, CH 3 .C6H 3 <^\C.CH 3 , red pig- 

 NH NH 



1 Blumenthal, Arch. f. (Anat. u.) Physiol., 1901, Suppl., and 1902, with Rosenfeld, 

 Charite annalen, 27, and Hofmeister's Beitrage, 5; Lewin, Hofmeister's Beitrage, 1; 

 Mayer, Arch. f. (Anat. u.) Physiol., 1902, Zeitschr. f. klin. Med., 47, and Zeitschr. f. 

 physiol. Chem., 29, 32; Scholz, ibid., 38; Ellinger, ibid. t 39; Gentzen, " Ueber die Vor- 

 etufen des Indols bei der Eiweissfaulnis im Thierkorper," Inaug. -Dissert.. Konigsberg, 

 1904. 



2 Harnack, Zeitschr. f. physiol. Chemie, 29; Scholz, 1. c., Moraczewski, Centralbl. 

 f. innere Med.. 1903. 



