60 DR ANDERSON ON CODEINE, AND 
times, it may be entirely removed, and crystals obtained which are pure hydro- 
chlorate of codeine. For the preparation of codeine, however, it would be worse 
than useless to carry the process thus far, as the solubility of hydrochlorates of 
codeine and ammonia differs so little that much of the former salt would be lost; 
but by carrying it a certain length, the greater part of the sal-ammoniac may be 
separated without any material loss of codeine, and the subsequent steps of the 
process much facilitated. The crystals so obtained being dissolved in boiling 
water, strong solution of caustic potash is added in excess, when codeine is in 
part precipitated as an oil, which by-and-by concretes into a solid mass, and is 
partly deposited in crystals as the solution cools. By evaporating the fluid, another 
crop of crystals is obtained; and, finally, when the mother-liquor has been concen- 
trated to a very small bulk, it becomes filled on cooling with long silky needles of 
morphia, which has been retained in solution by the excess of potash. A certain 
quantity of morphia appears always to remain in solution along with the codeine; 
at least I have found it in all the mother-liquors I have examined, although its 
quantity appears to vary considerably. Its presence in this solution has been 
observed before, and it has been stated that it exists in the form of a double salt 
with codeine; this, however, is not consistent with my own experience, at least 
the salt separated from the muriate of ammonia by successive crystallisations 
contained no morphia, but, as has been already stated, was pure hydrochlorate 
of codeine. 
The crystals of codeine precipitated by potash, in the manner described, are 
always more or less coloured. They are purified by solution in hydrochloric acid, 
boiling with animal charcoal, and reprecipitation with a slight excess of potash, 
and the precipitate obtained finally dissolved in ether, to separate any morphia 
which may adhere to it. For this purpose hydrous ether is best adapted; and 
it ought to be free from alcohol, as if any be present, the ether evaporates, and a 
syrupy fluid is left behind, which refuses to crystallise. When the ether is anhy- 
drous, it dissolves codeine with much greater difficulty, and by evaporation small 
crystals are deposited, which are anhydrous. 
The codeine employed for analysis was dried at 212°. The three first were 
made with codeine crystallised from hydrous ether, which lost two equivalents of 
water at 212°; the last was anhydrous codeine in small colourless crystals. 
16:1385 ... of carbonic acid, and 
6°120 grains of codeine, with oxide of copper, gave 
iy 
3888 ... of water. 
5:896 grains of codeine, with oxide of copper, gave 
Il. { 15°616 ... of carbonic acid, and 
3°737 ~~... of water. 
{ 4-688 grains of codeine, with chromate of lead, gave 
UI. < 12°392 ... of carbonic acid, and 
| 3-015... of water. 
ee 
