PART IT.
Materia Medica.
285
when it afforded similar results with the majority of the testsemployed. Hence this part of Turkey opium appears to he amodification of gluten combined with resin, extractive, and apeculiar salt
3. East Indian opium has a strong empyreumatic smell, andless of the peculiar narcotic heavy odour of the Turkey opium;the taste is more bitter, and equally nauseous, but it has lessacrimony: it agrees with the Turkey opium in its other sensi-ble qualities, except that its colour is blacker, its texture lesstenacious; and when triturated with water no insoluble plasticresiduum is left, but it is altogether taken up; eight parts intwelve being dissolved, and the remainder suspended in thefluid.
The aqueous solutions of both kinds of opium are transpa-rent when altered, that of the East Indian having the deepestbrown colour; both redden litmus paper; neither is decomposedby alcohol, but both are precipitated by the carbonates of pot-ass and of soda, and by pure ammonia; precipitates are alsoformed by solutions of the muriate and nitrate of mercury, theacetate and super-acetate of lead, the nitrate of silver, and thesulphates of copper, of zinc, and of iron. They are also pre-cipitated by infusion of galls; the precipitate, as doctor Dun-can justly observer, resembling more that produced by cin-ch&nin, than that by gelatine. * The solution of icetate ofbarytes does not alter the solutions of Turkey opium, but pro-duces a copious precipitate with those of the East Indian;oxalic acid precipitates both, but the latter more copiously.From these experiments opium appears to contain resin, gum,bitter extractive, a peculiar crystallizable salt, and sulphate oflime, which appears to be very abundant in the East Indianopium: the Turkish contains besides, a species of gluten, andperhaps caoutchouc.
When ether is used as a menstruum for opium, and the re-sin and extractive which it takes up are separated by evaporat-ing the tincture on the surface of water, the pellicle of resindeposited is nearly insipid, while the extractive dissolved inthe water has an intensely bitter taste: from this fact, and thecircumstance already mentioned of opium becoming inertwhen boiled in water, we might venture to conclude thatthe narcotic principle resides in the extractive. Derosne in1804, asserted that the activity of opium depends on a pecu-liar salt. He evaporated a watery infusion of opium to theconsistence of syrup, and digested the gritty precipitate formedby this evaporation in hot alcohol: as the solution cooled, a saltformed, which by repeated solutions and crystallizations was
« Edinburgh New Dispensary, 5th edit. 332.