214 DR T. ANDERSON ON SOME OF THE 



The relationship thus brought out between two substances which have 

 been long described as isolated constituents of opium is entitled to much con- 

 sideration, and is the first step towards the simplification of the chemistry of 

 a substance so remarkable for its complexity. As a matter of speculation, the 

 opinion has long been entertained, that when several well-defined substances exist 

 in the same plant, they must bear some relation to one another, and it has not 

 unfrequently happened that this idea has been borne out by the formulae assigned 

 to them. Quinine and cinchonine, which were once supposed to differ only in the 

 proportion of oxj'gen they contain, may be cited as striking instances ; and it was 

 commonly believed that these two substances must be related in the same man- 

 ner as two different oxides of a metal, and by the proper use of oxidizing and 

 reducing agents must be mutually convertible. But neither in this nor in any 

 similar instance has the anticipated conversion been realized, except with harma- 

 line and harmine, the two bases of the Peganum harmala, and it is somewhat 

 remarkable, that theformcr is converted into the latter by the oxidation of two 

 equivalents of hydrogen, exactly as I have found to occur with narcotine, except- 

 ing that there is no splitting up into two products, as with the latter substance. 



But although the conversion of other alkaloids has not hitherto been success- 

 ful, there cannot be a doubt that the close approximation in the formulae of sub- 

 stances occurring in the same plant, indicates some natural connexion, and it is 

 important that all such relations, where they exist, should be kept distinctly in 

 view. For this reason, I propose to direct attention to those which have been 

 brought out by the investigation of the compounds of opium. 



Between the two best known of these alkaloids, morphia, and codeine, a very 

 simple relation subsists. Their formulae are, 



Morphia, C 34 H 19 NO c 



Codeine, . . . . C 3G H 21 NO G 



Difference, . C, H 2 



and their relation is that of the two immediately adjoining members of a homo- 

 logous series. Yet there is little, if anything, except their formulas, to bear out 

 the opinion that they actually are homologous. They show but little of that close 

 similarity in properties, which frequently renders the separation and distinction 

 of such substances so difficult ; and especially in their relations to solvents, there 

 are very marked differences. Still the connexion is worthy of mention ; the more 

 especially, as the experiments of Mr How* lead to the opinion that they are both 

 nitryl bases. 



Thebaine and codeine are likewise somewhat closely connected, — 



Thebaine, C 38 H 21 N0 6 



Codeine C 3U H 21 NO fi 



Difference, . C 2 

 Quarterly Journal of Chemical Society, vol. vi., p. 125. 



