FORMATION OP INDIGO-BLUE. 229 



Indicanine is formed from indican simply by the latter taking 

 Bp water and losing 1 equivalent of indiglucine, as will be seen 

 from the following equation : — 



1 eq. Indican C M H 3 i NO M | __ ( C£ U n NO* 1 eq. Indicanine. 



2 eqs. Water H a O a ) "" I C la H 10 O u 1 eq. Indiglucine. 



C„ H„ NO. C M H„NO„ 



The indiglucine formed in the process is contained in the 

 brown syrupy deposit which falls on adding ether to the alco- 

 holic solution of the indicanine. Some of this deposit, after 

 the liquid had been poured off, was dissolved again in alcohol, 

 the solution was mixed with an excess of alcoholic solution of 

 acetate of lead, which produced a brown glutinous precipitate, 

 and to the filtered liquid was added an excess of ammonia, 

 which gave a bulky sulphur-yellow precipitate. This pre- 

 cipitate was collected on a filter, washed with water and de- 

 composed with sulphuretted hydrogen, and the filtered liquid 

 was agitated with animal charcoal until it had lost the yellow- 

 ish tint which it possessed at first. The liquid having been 

 again filtered was mixed with acetate of lead and ammonia, 

 which produced a milk-white precipitate. This precipitate 

 after being filtered off was redissolved in a mixture of alcohol 

 and acetic acid, and by the addition of a small quantity of 

 ammonia a white precipitate was again produced, which was 

 filtered off and washed with alcohol. 



1.0230 grm. of this precipitate dried in vacuo gave 0.4780 

 grm. carbonic acid and 0.1510 water. 



0.6095 grm. gave 0.5780 grm. sulphate of lead. 

 In 100 parts it contained therefore 



Carbon 12.74 



Hydrogen 1.64 



Oxygen 15.85 



Oxide of Lead. . 69.77 



100.00 

 If the oxide of lead, the amount of which stands in no 



