Pack this firmly in a percolator, and pass rectified spirit through it till the spirit ceases to be coloured. Concentrate the spirituous solution by distillation, so long as no deposit forms, and pour the residue, while hot, into 12 times its volume of cold distilled water. Filter through calico, and wash the residue on the filter with distilled water, till the fluid ceases to precipitate with ammonia. To the united filtered liquid add the ammonia in slight excess, let the precipitate completely subside, pour off the supernatant fluid, collect the precipitate on a filter, and wash it with distilled water till the fluid passes colourless. Diffuse the moist precipitate through 12 oz. of distilled water, and add gradually, with diligent stirring, sufficient hydrochloric acid to make the fluid feebly but persistently acid.
Then add the animal charcoal, digest at a gentle heat for 20 minutes, filter, and allow the liquid to cool. Add ammonia in slight, excess, and when the precipitate has completely subsided, pour off the supernatant liquid, collect the precipitate on a filter, and wash it with cold distilled water till the washings cease to be affected by nitrate of silver accidental with nitric acid. Lastly, dry the precipitate, first by imbibition, with filtering paper, and then by the application of a gentle heat.
Prop. Pure veratrine is perfectly white; but as usually met with, it is a yellowish or greenish-white powder; it is highly acrid; uncrystallisable; scarcely soluble in water, soluble in ether, and freely soluble in hot alcohol; heated to about 125° Fahr., it fuses like wax, and solidifies, upon cooling, to a transparent yellow mass. With the dilute acid it forms salts, which are either amorphous or difficulty crystallisable. The smallest possible portion of its powder causes violent sneezing.
Tests. 1. Potassa, ammonia, and their carbonates, give flocculent white precipitates
which at first are not crystalline under the microscope, but which, after some minutes, assume the appearance of small scattered clusters of short prismatic crystals; they are insoluble in excess of potassa and its carbonate, and only very slightly so in excess of ammonia.—2. With sulphuric acid it strikes an intense red colour, changing afterwards to crimson, and finally to violet.—3. A dilute acetic solution of veratrine is turned to a superb red by strong sulphuric acid.
Veratrine is distinguished from brucine and the other alkaloids by its fusibility—by the crystalline form of its precipitate with potassa, and—by its reaction with oil of vitriol.
Uses, &c. “As an external application, it has been efficaciously employed by Magendie in France, and by Dr Turnbull in this country; but the extravagant eulogies of the latter have not tended to confirm the reputation of this remedy.” (Dr A. T. Thomson.) From 6 to 12 gr., dissolved in 1 fl. oz. of rectified spirit, as a liniment; or 30 gr., mixed with 1 dr. of olive oil, and 1 oz. of lard, as an ointment, have been occasionally found very serviceable in neuralgia, and other like painful affections, and in gouty and rheumatic paralysis. As an internal remedy it possesses no advantage, as it merely acts as a violent and depressing cathartic.—Dose, 1⁄24 to 1⁄16 gr. In larger doses it acts as a powerful irritant poison. For antidotes, &c., see Alkaloid.
VERA′TRUM. See White hellebore.
VER′DIGRIS. Syn. Ærugo, L.; Vert-de-gris, Fr. This is a mixture of several basic acetates of copper which have a green or blue colour. It is obtained in the wine districts of the south of Europe, by the action of refuse grapes, from which the juice has been expressed, on thin sheets of copper. When pure it should dissolve, almost entirely, and without effervescence, in dilute sulphuric acid. It is very poisonous; for antidotes, see Copper.
An inferior quality of verdigris is now prepared from pommage, or apple marc, in the cider districts of England.