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 
unfrequentlyhappened that this idea has been borne out by the formule assigned 
to them. Quinine and cinchonine, which were once supposed to differ only in the 
proportion of oxygen 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 theformer 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 formule 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. [or 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 formule are, 
Morphia,  . : 5 ‘ Copan eNO, 
Codeine, c . 3 2 C,, H,, NO, 
Difference, . CoH, 
and their relation is that of the two immediately adjoining members of a homo- 
logous series. Yet there is little, if anything, except their formule, 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, . ci 5 ; C,, H,, NO, 
Codeine, 3 = 5 . role m3 iN 0, 
Difference, C, 
* Quarterly Journal of Chemical Society, vol. vi., p. 125. 
