Robinson's process, modified by Gregory, somewhat resembles that just described, but the aqueous infusion is first neutralised with car bonate of lime, and chloride of calcium is then used in the place of chloride of lead.
Mohr and Thibouinary's method is based on the solubility of mor phine, and insolubility of the other bases, in limo water. It consists in thoroughly exhausting the opium by boiling two or three times in water, gradually adding the resulting decoction to boiling diluted milk of lime, filtering, evaporating, and neutralising the limo by chloride of ammonium, and finally purifying the morphine thus precipitated by treatment with animal charcoal and recrystallisation.
Estimation of morphine. 31. Fordos has recently (1857) published a process for determining the amount of morphine contaiued in any specimen of opium. A weighed quantity is macerated with water for twenty-four hours, the insoluble portion triturated hi a mortar, thrown on a filter, and washed three or four times with water. The whole of the liquors are then mixed together, and a third part of them treated gradually with ammonia until, after brisk agitation, a slight ammoniacal odour is perceptible; by this operation the quantity of ammonia neces sary for the precipitation of the whole of the bases is known ; the latter cannot, however, be at once collected, as much resinous and colouring matter is also thrown down by the ammonia. The next step therefore is to add an equal volume of alcohol to the remaining two thirds of the mixed liquors, and then double the quantity of ammonia used with the one-third. Tho alcohol has the effect of keeping in solution all the resin and colouring matter; and although it retard), tho precipitation of the morphine, the whole of that alkaloid goes down in crystals after standing for three days, and may be collected on a tared filter, washed with ether and chloroform to separate narcotine, and finally weighed. The amount of opium recommended to be operated upon is fifteen grammes (2311 grains).
Morphine is colourless and inodorous, but has a persistent bitter taste. It cryatallisea in transparent prisms, is soluble in one thousand parts of cold, and four hundred of boiling, water. It is readily soluble
in boiling alcohol, but insoluble in ether or chloroform; ammonia also dissolves it slightly. Its alcoholic solution communicates powerful left-handed rotation to a polarised ray. Heated, it parts with its water of crystallisation, melts, and on cooling solidifies into a radiated crystalline mass.
Morphine is exceedingly poiaonous. It is a powerful base, com bining with acids to form a well marked aeries of crystalline salts, of which the hydroclilorate and acetate are extensively used in medicine.
Hydrochlorate of morphine H„ NO,, 6Aq.), frequently called muriate of morphia, is a colourless, inodoroua, bitter salt, which crystallisee in plumose acicular crystals : it ie soluble in 16 to 20 times its weight of water ; and when boiling water is saturated with it, a crystalline mass is formed as it cools ; it is also dissolved by alcohol. When exposed to a red heat, it is totally decomposed and dissipated. Its preparation from opium has already been described.
Acetate of morphine is prepared by dissolving the alkaloid in acetic, acid, and evaporating the solution so that crystals may form ; these are not however very readily procured, and by the evaporation of the solution a part of the acid is eometimea dissipated, and a portion of the acetate, suffering partial decomposition, is rendered insoluble in water.
The crystals are in the form of colourless radiating needles, whist are very readily dissipated by exposure to heat and, like the other salts of morphine, are decomposed by ammonia, potash, and soda, the morphine being precipitated. Acetate of morphine is slightly deli queseent.
Meconate of morphine, which is the natural salt existing in opium, does not crystallise; it is soluble in water and in alcohol.
Sulphate of morphine HO, SO, + 5Aq.) crystallises in needles grouped in bundles ; it is soluble in about twice its weight of water.
Bisulphate of morphine is procured by supersaturating the neutral salt with sulphuric acid ; the excess of acid is to be removed by ether, which does not dissolve the biealt.