130 Dr. SchuntK on the Formation of Indigo-blue. 



however, contained in the silver salt, the analysis of which has 

 just been given, was very small, since, as may be inferred from 

 the composition of the salt, it was to that of the acetic acid in 

 the proportion of 1 equivalent of the former to 23 equivalents 

 of the latter. 



Having described all the products to which the decomposition 

 of indican with acids gives rise, it will now be possible to give 

 an account of the manner in which these various products are 

 formed, and of the relation in which they stand to one another. 



The decomposition of indican, after taking up several equiva- 

 lents of water, into 1 equivalent of indigo-blue or indirubine and 

 3 equivalents of indiglucine, will be evident at once from a com- 

 parison of the formulae of these bodies. 



The formation of leucine will also be easily understood when 

 it is considered that indigo-blue and 10 equivalents of water 

 contain the elements of 1 equivalent of leucine, 1 equivalent of 

 formic acid, and 2 equivalents of carbonic acid, as the following 

 equation will show : — 

 1 TV.! ri6U5 ivrna ^ f C'^HiSNO'* leq. leucine. 



lOeXaSr H- O'o} = ^ ^' ^'' Oneq'.form.cacul. 

 lUeqs.^ater n U_J 1 ^^ 04 2eqs.carb. acid. 



Such a decomposition as this can of course only take place 

 before the elements of indican have arranged themselves in such 

 a manner as to form indigo-blue, which is a body of far too 

 stable a nature to undergo any decomposition by the action of 

 dilute acids. 



In order to explain the formation of indifulvine, it is necessary 

 to take into consideration the simultaneous formation of formic 

 acid. Indican may be supposed, after taking up 5 equivalents 

 of water, to split up into 1 equivalent of «-indifulvine, 2 equiva- 

 lents of indiglucine, and 3 equivalents of formic acid, as will be 

 seen from the following equation : — 



1 • J- nsa uqnvTr\s4-^ f C^-H'^'NO^ 1 eq.ffl-indifulvine. 

 leq.mdicanC^^H^'NOn ^ J c^^w- 0^^ 2 eqs. indiglucine. 

 5eqs.water H^ 0^ J 1 c« H« 0^^ 3 eqs. formic acid. 



The following equation shows how the other modification of 

 indifulvine may be supposed to take its rise : — 



rc44 H'^N^O^leq.i-indifulvine. 

 2eqs.indicanCi'>4H«2N2068\_J C^ H'*" O^^^eqs. indiglucine. 

 7eqs.water H^ 07 /~iC'"H'" O^^S eqs. formic acid. 



Qio4jj69]y2Q7& I^C^ 0* 2eqs. carb.acid. 



C104H6'9N2O75 



