372 



Dr. C. R. A. Wright on the [Mar. 9, 



bromide is evolved during the first stages of this change, but subsequently 

 this body is produced in some little quantity. 



The precipitate thrown down by carbonate of soda before this further 

 change ensues, appears to consist of a variable mixture of at least three 

 substances, two of which are readily soluble in ether, while the third is but 

 sparingly soluble in that menstruum ; all are bases, the one insoluble in 

 ether, and one of those soluble containing bromine : the one apparently first 

 formed is produced by a reaction precisely analogous to that whereby chloro- 

 codide is generated, viz. — 



Codeia. Bromocodide. 

 C 18 H 21 N0 3 + H Br = H 2 O + C M H 20 Br N0 2 , 



and is therefore termed bromocodide ; this base appears to be acted on 

 further with great ease, giving rise ultimately to the other two, the first 

 of which has the constitution of codeia less one equivalent of oxygen, or 

 C H 21 N0 2 , and is therefore provisionally named Deoxycodeia ; whilst the 

 second has the composition of four molecules of codeia coalesced together, 

 one of the 84 H atoms in the product being replaced by Br ; it is therefore 

 provisionally termed Bromotetracodeia, the simplest mode of representing 

 the simultaneous formation of these two bases being as follows : — 



Bromocodide. Codeia. Deoxycodeia. Bromotetracodeia. 



C u H 20 Br N0 2 +4 C„ H 21 N0 3 =C I8 H a N0 2 +C 72 H 88 Br N, 12 . 



Owing to the ease with which bromocodide is altered, it is a matter of 

 some difficulty to obtain it in even an approximately pure condition, as 

 the complete separation of deoxycodeia appears impracticable when this 

 base has once been produced. The product of the action of three parts 

 48 per cent, acid on one part codeia on the water-bath for from one to two 

 hours is precipitated by excess of sodium carbonate and the precipitate 

 collected on filters ; unaltered codeia is for the most part separated thus, 

 being contained in the filtrate. Extraction of .the mass with ether and 

 agitation of the ethereal solution with HBr furnishes crude bromocodide 

 hydrobromate, which may be purified by a repetition of the process, frac- 

 tional precipitation being resorted to to get rid of traces of colouring- 

 matters : the purified hydrobromate thus obtained was a viscid colourless 

 liquid which utterly refused to crystallize, and dried up to a gum-like mass 

 over S0 4 H 2 . Dried at 100°, the powdered gum gave these numbers *: — 



0-3500 grm. gave 0'6340 C0 2 and 0-1580 H 2 0. 



0-230 grm, boiled with N0 3 H and AgN0 3 gave 0-1900 Ag Br. 



* All combustions given in this paper were made with lead chroniate and finished in 

 a stream of dry oxygen. 



