206 Mil. E. SCHUNCK ON THE 



If the first formula be doubled it gives C 44 Hgo N 2 6 , and 

 if from this be deducted 1 equivalent of water and 2 equiva- 

 lents of oxygen it gives the second formula C44 H 19 N 2 3 . 



For the sake of distinction I think it may be of advantage 

 to apply to the first of these modifications of indifulvine, the 

 term a indifulvine and to the second that of b indifulvine. 

 The manner in which these bodies are derived from indican 

 can only be understood after all the products of decomposi- 

 tion have been treated of. 



Indihumine. 



This substance has the appearance of a sepia-brown powder, 

 which is insoluble in water and alcohol, but soluble in alkaline 

 liquids forming brown solutions, from which it is re-precipitated 

 by acids in brown flocks. When heated on platinum it burns 

 without melting leaving some charcoal which easily burns 

 away. Boiling nitric acid decomposes it easily, forming a 

 yellow solution which on evaporation leaves an orange- 

 coloured residue insoluble in water. Indihumine is not 

 always formed in any great quantity in the decomposition of 

 indican by acids. Sometimes indeed it cannot be detected 

 among the products of decomposition, and usually it is 

 present only in minute quantities. What are the circum- 

 stances which determine its formation in particular cases 

 I am unable to say. On the only occasion on which I 

 obtained a sufficient quantity for analysis it was procured 

 from an alcoholic extract of woad by evaporating, adding 

 water to the residue and filtering, then adding sulphuric acid 

 to the watery solution containing indican, filtering again, 

 allowing the solution to stand for twenty-four hours, filtering 

 off the indigo-blue and other products which had separated, 

 boiling the liquid, collecting the brown powder which was 

 deposited during the ebullition on a filter, washing it with 

 water and then treating it with a boiling mixture of alcohol 

 and ammonia until nothing more dissolved. The insoluble 



