Fig. 36.—Photo-micrograph of crystals
of hydrochloride of morphine, × 50.
(R. J. M. Buchanan.)
Taylor‘s method for the extraction of morphine may be briefly described as follows:
The liquid—porter, &c.—to be examined is acidified with acetic acid; or, if a solid organ is to be tested, it must be cut into thin slices and placed in distilled water acidified in a similar way. In either case the liquid is digested for one or two hours at a gentle heat, and filtered. Acetate of lead is now added to the filtrate until no further precipitation occurs; the liquid is then boiled and filtered. The meconic acid remains on the filter as meconate of lead, while the filtrate contains the morphine as acetate. The liquid is freed from excess of lead by passing through it a current of sulphuretted hydrogen, filtered to remove the precipitated sulphide of lead, and the resulting liquid evaporated to an extract on a water bath, and treated with alcohol. The alcoholic solution on evaporation gives acetate of morphine, which may then be tested.
Fig. 37.—Photo-micrograph of meconic acid
crystallised from aqueous solution, × 50.
(R. J. M. Buchanan.)
Fig. 38.—Photo-micrograph of meconic acid
crystallised from an alcoholic solution, × 50.
(R. J. M. Buchanan.)
The meconate of lead which remains on the filter is decomposed by treating it with dilute sulphuric acid, and gently boiling the mixture. The filtered liquid should be neutralised before the tests for the presence of meconic acid are applied.
The reactions of both morphine and meconic acid are best seen from the following Table:—