QUINIA, or QUININE. An alkaline base obtained from yellow bark ; the Cinchona cord folic. This substance, combined with sulphuric acid, forms the sulphate of quinia, which is now so ex tensively used as a medicine, and as a substitute for the various forms of Peru vian bark. To obtain quinia, bruised yellow bark is boiled in repeated portions of water, acidulated by sulphuric acid, till all its soluble matters are extracted ; a little excess of quicklime is then added to the strained decoction, and the precipi tate which is formed is collected, washed, and carefully dried; it is then digested in alcohol, which takes up the quinia, and from which it may be obtained in the form of a yellowish uncrystallizable substance by careful evaporation. It is dissolved in dilute sulphuric acid, and the sulphate of quinine or quinia, crys tallizes from its concentrated solution in fine silky prisms, which effloresce on ex posure to air. Sulphate of quinia is diffi cultly soluble in water, and bitter. It is more strictly a disulphate of Cinchona exists in all barks to some extent ; and there are several modes of separating the quinine from the cinchona, viz : 1. By evaporating the alcoholic solu tion on cooling, the cinchona crystallizes, while the quinine remains dissolved.
2. Digestion in ether dissolves the quinine, and leaves the cinchona.
3. We may supersaturate slightly the two bases with sulphuric acid. Now as the supersuiphate of quinine is sparingly soluble, the liquor need only to be evap orated to a proper point to crystallize out that salt, while the supersulphate of cin chona continues in solution with very little of the other salt. Even this may be
separated by precipitating the bases, and treating them, as above prescribed, with alcohol or ether.
One pound of bark rarely yields more than two drachms of the bases. One pound of red bark afforded, to Pelletier and Caveutou, 74 grains of cinchona, and 107 grains of quinine.
Quinine is composed of 7516 carbon, 7.52 hydrogen, 8.11 azote, and 8.61 oxy gen.
The salts of quinine are distinguished by their strong taste of Peruvian bark, and if crystallized, by their yearly lustre. Most of them are soluble in water, and some also in ether and alcohol. The sol uble salts arc precipitated by the oxalic, and tartaric acids, and by the salts of these acids. Infusion of nutgalls also precipitates them.
The sulphate of quinine is the only ob ject of manufacturing operations. Upon the brownish viscid mass obtained in any of the above processes for obtaining quinine, pour very dilute sulphuric acid, in sufficient quantity to produce satura tion. The solution must be then treated with animal charcoal, filtered, evaporated, allowed to cool, when it deposits crys tals. 1000 parts of barks afford, upon an average, 12 parts of sulphate. The sulphate of cinchona, which is formed at the same time, remains dissolved iu the mother-waters.