exceeding difficulty in hot water; it dissolves sparingly in cold dilute spirit of wine, more readily in hot spirit of wine, and the most freely in absolute alcohol. From hot alcoholic solutions the greater portion of the dissolved cinchonia separates upon cooling in a crystalline form. Solutions of cinchonia taste bitter, and manifest alkaline reaction. Cinchonia is insoluble in ether.* 2, Cinchonia neutralizes acids completely. The salts have the bitter taste of the bark; most of them are crystallizable; they are generally more readily soluble in water and in spirit of wine than the corresponding quina compounds. Ether fails to dissolve them. 3. Cinchonia, when heated cautiously, fuses at first without loss of water; subsequently white fumes arise which, like benzoic acid, condense upon cold substances, in the form of small brilliant needles, or as a loose sublimate, a peculiar aromatic odor being exhaled at the same time. If the operation is conducted in a stream of hydrogen gas, long, brilliant prisms are obtained (Hlasiwetz). 4. Potassa, ammonia, and the neutral carbonates of the alkalies produce in solutions of salts of cinchonia a white, loose precipitate of CINCHONIA, which does not redissolve in an excess of the precipitants. If the solution was concentrated, the precipitate does not exhibit a distinctly crystalline appearance, even though viewed through a lens magnifying 200 times; but if the solution was so dilute that the precipitate formed only after some time, it appears under the microscope to consist of distinct crystalline needles aggregated into star-shaped tufts. 5. Bicarbonate of soda and bicarbonate of potassa precipitate cinchonia in the same form as in 4, both from neutral and acid solutions, but not so completely as the simple carbonates of the alkalies. In solutions containing 1 part of cinchonia to 200 parts of water and acid, the precipitate still forms immediately; its quantity increases after standing some time. 6. Concentrated sulphuric acid dissolves cinchonia to a colorless fluid, which upon application of heat first acquires a brown, and finally a black color. Addition of some nitric acid leaves the solution colorless in the cold, but upon application of heat the fluid, after passing through the intermediate tints of yellowish-brown and brown, turns finally black. 7. The addition of chlorine water to the solution of a salt of cinchonia fails to impart a color to the fluid; if ammonia is now added, a yellowish-white precipitate is formed. Recapitulation and Remarks. $234. The alkaloids of the second group are altered or precipitated by various other reagents besides those mentioned above; the reactions are, however, not adapted to effect their individual detection and separation. Thus, for instance, bichloride of platinum produces in solutions of the salts of the three alkaloids belonging to this group, a yellowish * The cinchonia of commerce usually contains in admixture another alkaloid, called cinchotina, which is soluble in ether. This alkaloid crystallizes in large rhomboidal crystals of brilliant lustre, which fuse at a high temperature, and cannot be sublimed, even in a stream of hydrogen gas (Hlasiwetz). white precipitate, chloride of mercury a white precipitate, tincture of galls a yellowish-white, flocculent precipitate, &c. Narcotina and quina being soluble in ether, whilst cinchonia is insoluble in that menstruum, the former may be most readily separated by this means from the latter alkaloid. For this purpose the analyst need simply mix the solution of the three alkaloids with ammonia in excess, then add ether, and separate the solution of quina and narcotine from the undissolved cinchonia. If the ethereal solution is now evaporated, the residue dissolved in hydrochloric acid and a sufficient amount of water to make the dilution as 1:200, and bicarbonate of soda is then added, the narcotina precipitates, whilst the quina remains in solution. By evaporating the solution, and treating the residue with water, the quina is obtained in the free state. THIRD GROUP. NON-VOLATILE ALKALOIDS WHICH ARE PRECIPITATED BY POTASSA FROM THE SOLUTIONS OF THEIR SALTS, AND DO NOT REDISSOLVE TO A PERCEPTIBLE EXTENT IN AN EXCESS OF THE PRECIPITANT; BUT ARE NOT PRECIPITATED FROM (even somewhat concentrated) ACID SOLUTIONS BY THE BICARBONATES OF THE FIXED ALKALIES: Strychnia, Brucia, Veratria. 24 2 + a. STRYCHNIA, or STRYCHNINE (CH2 N ̧ O ̧ = Sr). 1. Strychnia appears either in the form of white, brilliant rhombic prisms, or, when produced by precipitation or rapid evaporation, as a white powder. It has an exceedingly bitter taste. It is nearly insoluble in cold, and barely soluble in hot water. It is insoluble in absolute alcohol and ether, and difficultly soluble in dilute spirit of wine. It does not fuse when heated. It is exceedingly poisonous. All the 2. Strychnia neutralizes acids completely. The salts of strychnia are, for the most part, crystallizable; they are soluble in water. salts of strychnia have an intolerably bitter taste and are exceedingly poisonous. 3. Potassa and carbonate of soda produce in solutions of salts of strychnia white precipitates of strychnia, which are insoluble in an excess of the precipitants. Viewed through a lens magnifying one hundred times the precipitate appears as an aggregate of small crystalline needles. From dilute solutions the strychnia separates only after the lapse of some time, in the form of crystalline needles, which are distinctly visible even with the naked eye. The preci 4. Ammonia produces the same precipitate as potassa. pitate redissolves in an excess of ammonia, but after a short time—or if the solution is highly dilute, after a more considerable lapse of time—the strychnia crystallizes from the ammoniacal solution in the form of needles, which are distinctly visible with the naked eye. 5. Bicarbonate of soda produces in neutral solution of salts of strychnia a precipitate of strychnia, which separates in fine needles shortly after the addition of the reagent, and is insoluble in an excess of the precipitant. But upon adding one drop of acid (so as to leave the fluid still alkaline) the precipitate dissolves readily in the liberated carbonic acid. The addition of bicarbonate of soda to an acid solution of strychnia causes no precipitation, and it is only after the lapse of twenty-four hours, or even a longer period, that strychnia crystallizes from the fluid in distinct prisms, in proportion as the free carbonic acid escapes. If a concentrated solution of strychnia, supersaturated with bicarbonate of soda, is boiled for some time, a precipitate forms immediately; from dilute solutions this precipitate separates only after concentration. 6. Sulphocyanide of potassium produces in concentrated solution of salts of strychnia immediately, and in dilute solutions after the lapse of some time, a white crystalline precipitate, which appears under the microscope as an aggregate of flat needles, truncated or pointed at an acute angle, and is but little soluble in an excess of the precipitant. 7. On putting a drop of concentrated sulphuric acid in a watch-glass, and adding to it some strychnia or a little of a salt of strychnia, solution ensues without any particular reaction; but if a drop of solution of chromate of potassa is now added to the fluid, the latter instantly acquires a deep blue color, which speedily changes to red (Otto). If the strychnia is rubbed together with binoxide of lead and concentrated sulphuric acid containing 1 per cent. of nitric acid, the mass acquires first a blue, then a violet color, which changes to red, and, finally, to greenish-yellow (E. Marchand). The former reaction (Otto's) loses in distinctness, or even altogether fails to manifest itself, if the substance contains admixtures of some other organic compounds, e. g., quina, sugar (Brieger). But by the second method (Marchand's) strychnia may be clearly detected even when mixed with much sugar. Ferricyanide of potassium also will produce the same reaction (W. Davy); with this oxidizing agent the change from violet to red and yellow takes place more slowly. 8. Chloride of mercury produces in solutions of salts of strychnia a white precipitate, which changes after some time to crystalline needles aggregated into stars, and distinctly visible through a lens. Upon heating the fluid these crystals redissolve, and upon subsequent cooling of the solution the double compound recrystallizes in distinct needles. 9. Strong chlorine water produces in solution of salts of strychnia a white precipitate, which dissolves in ammonia to a colorless fluid. 10. Concentrated nitric acid dissolves strychnia and its salts to a colorless fluid, which becomes yellow upon the application of heat. 1. Crystallized brucia (Br+7 aq.) appears either in the form of transparent, straight rhombic prisms, or in that of crystalline needles aggregated into stars, or as a white powder composed of minute crystalline scales. Brucia is difficultly soluble in cold, but somewhat more readily in hot water. Both absolute and dilute alcohol dissolve it freely, but it is insoluble in ether. Its taste is intensely bitter. When heated, it fuses with loss of its water of crystallization. 2. Brucia neutralizes acids completely. The salts of brucia are readily soluble in water, and of an intensely bitter taste. Most of them are crystallizable. 3. Potassa and carbonate of soda throw down from solutions of salts of brucia a white precipitate of brucia, which is insoluble in an excess of the precipitant. Viewed under the microscope, immediately after precipitation, it appears to consist of very minute grains; but, upon further inspection, these grains are seen-with absorption of water-to suddenly form into needles, which latter subsequently arrange themselves into concentric groups. These successive changes of the precipitate may be traced distinctly even with the naked eye. 4. Ammonia produces a whitish precipitate in solutions of salts of brucia, which appears at first like a number of minute drops of oil, but changes subsequently-with absorption of water-to small needles. The precipitate redissolves, immediately after separation, very readily in an excess of the precipitant, but after a very short time-or, in dilute solutions, after a more considerable lapse of time-the brucia, combined with crystallization water, crystallizes from the ammoniacal fluid in small concentrically grouped needles, which addition of ammonia fails to redissolve. 5. Bicarbonate of soda produces in neutral solutions of salts of brucia a precipitate of brucia, combined with crystallization water; this precipitate separates after the lapse of a short time, in form of concentrically aggregated needles of silky lustre, which are insoluble in an excess of the precipitant, but dissolve in free carbonic acid (compare strychnia). Bicarbonate of soda fails to precipitate acid solutions of salts of brucia ; and it is only after the lapse of a considerable time that the alkaloid separates from the fluid in regular and comparatively large crystals, in proportion as the carbonic acid escapes. 6. Concentrated nitric acid dissolves brucia and its salts to intensely red fluids, which subsequently acquire a yellowish-red tint, and turn completely yellow upon application of heat. Upon addition of protochloride of tin or sulphide of ammonium to the fluid heated to this point, no matter whether concentrated or after dilution with water, the faint yellow color changes to a most intense violet. 7. Addition of chlorine water to the solution of a salt of brucia imparts to the fluid a fine bright red tint; if ammonia is then added, the red color changes to yellowish-brown. 8. Concentrated sulphuric acid dissolves brucia to a faint rose-colored fluid. 9. Sulphocyanide of potassium produces in concentrated solutions of salts of brucia immediately, and in dilute solutions after some time, a granular crystalline precipitate, which, when viewed under the microscope, appears composed of variously aggregated polyhedral crystalline grains. Friction applied to the sides of the vessel promotes the separation of the precipitate. 10. Chloride of mercury also produces a white granular precipitate, which, when viewed under the microscope, appears composed of small round crystalline grains. + c. VERATRIA, or VERATRINE (CH22 NO) Ve. $237. 1. Veratria appears generally as a pure white, yellowish or greenishwhite powder, of acrid and burning, but not bitter taste; it is exceedingly poisonous. Veratria acts with great energy upon the mem branes of the nose; even the most minute quantity of the powder excites the most violent sneezing. It is insoluble in water; in alcohol it dissolves readily, but more sparingly in ether. At a gentle heat it fuses like wax, and solidifies upon cooling to a transparent yellow Some salts of veratria are mass. 2. Veratria neutralizes acids completely. crystallizable, others dry up to a gummy mass. They are soluble in water, and of acrid and burning taste. 3. Potassia, ammonia, and the simple carbonates of the alkalies produce in solutions of salts of veratria a flocculent, white precipitate, which, viewed under the microscope, immediately after precipitation, does not appear crystalline. After the lapse of a few minutes, however, it alters its appearance, and small scattered clusters of short prismatic crystals are observed, instead of the original coagulated flakes. The precipitate does not redissolve in an excess of potassa, and of carbonate of potassa. It is slightly soluble in ammonia, in the cold, but the dissolved portion separates again upon application of heat. 4. With bicarbonate of soda and bicarbonate of potassa the salts of veratria comport themselves like those of strychnia and brucia. However, upon boiling, the veratria separates readily, even from dilute solutions. 5. If veratria is acted upon with concentrated nitric acid, it agglutinates into small resinous lumps, which afterwards dissolve slowly in the acid. The solution presents a faint reddish-yellow color. 6. If veratria is treated with concentrated sulphuric acid, it also agglutinates at first into small resinous lumps; but these dissolve with great readiness to a pale yellow fluid, the color of which gradually increases in depth and intensity, and changes afterwards to a reddishyellow, then to an intense blood-red, subsequently to crimson, and finally to violet. 7. Sulphocyanide of potassium produces only in concentrated solutions of salts of veratria flocculent-gelatinous precipitates. 8. Addition of chlorine-water to the solution of a salt of veratria imparts to the fluid a yellowish tint, which, upon addition of ammonia, changes to a faint brownish color. In concentrated solutions chlorine produces a white precipitate. Recapitulations and Remarks. § 238. The alkaloids of the third group also are precipitated by many other reagents besides those above-mentioned, as, for instance, by tincture of galls, bichloride of platinum, &c. But as these reactions are common to all, they are of little importance in an analytical point of view. Strychnia may be separated from brucia and veratria by means of absolute alcohol, since it is insoluble in that menstruum, whilst the two latter alkaloids readily dissolve in it. The identity of strychnia is best established by the reaction with sulphuric acid and chromate of potassa, or with binoxide of lead or ferricyanide of potassium; also by the form of its crystals—when thrown down by alkalies-viewed under the microscope; and lastly, by the form of the precipitate which sulphocyanide of potassium and chloride of mercury produce in solutions of its salts. |