174 THE URINE. 



are accompanied by an internal formation of pus there is an 

 increased amount of organic sulphates in the urine, and this 

 fact may be used to judge whether the pus-forming stage 

 has been reached. This is the case in foetid bronchitis, 

 carcinoma of the stomach or intestine, diphtheria, pyaemia, 

 etc. If the formation is from putrefaction in the intestine 

 it will be diminished by taking antiseptic remedies, like 

 calomel, or those which, by their purgative action, remove 

 the contents of the intestine before, this putrefaction has 

 occurred. 



The compound of indol which is found in the urine 

 goes by the name of indican. The indol, 



C 6 H 4 CH 



CH 



formed by the putrefaction of albuminous substances, is 

 oxidized after it has been absorbed from the intestine or 

 elsewhere in the body and becomes indoxyl: 



C 6 H 4 COH 



I II 

 HN CH 



This unites with potassium and sulphuric acid to form 

 indican: 



C 6 H 4 C S0 4 K 



CH 



Indican may be easily oxidized by chlorin or other oxidiz- 

 ing agents, and then forms indigo blue: 



C 6 H 4 CO CO C 6 H 4 



I I I I 



C = C NH 



