NAPH′THALIN. C10H9. Syn. Naphthaline, Naphthalene. A white crystallisable, odorous, volatile substance, obtained from coal-tar.
Prep. The last portion of the volatile oily product is collected separately, and allowed to repose, when crude naphthalin separates in the solid state. By pushing the distillation until the residuum in the still begins to char, a further portion of dark-coloured naphthalin may be obtained. It is purified by resublimation a second, or even a third time.
Prop., &c. Soluble in alcohol and ether; slightly soluble in boiling water; melts at 176° Fahr.; boils at 412°; highly inflammable, burning with a red and smoky flame; with sulphuric acid, it unites to form sulpho-naphthalic acid. By the action of nitric acid upon naphthalin, numerous substances may be formed, the most interesting being nitro-naphthalin. Naphthalin has lately been extensively employed as a stimulating expectorant.—Dose, 5 to 20 gr.; or, preferably, 1⁄2 gr., frequently. Externally, made into an ointment, in dry tetters, psoriasis, &c. 30 gr. may be mixed with 1 oz. of lard.
NA′PLES YEL′LOW. See Yellow pigments.
NAR′CEIA. C23H20G9. Syn. Narceina, Narceia. A peculiar substance discovered by Pelletier in opium. It is obtained from the aqueous solution of opium, after it has been freed from morphia, and narcotina, by ammonia, by adding to it hydrate of lime, or preferably, baryta. On boiling the filtered solution, to expel the ammonia, and evaporating the liquid, crystals of narceine are gradually deposited. It may be purified by solution in hot alcohol and recrystallisation.
Prop., &c. White, silky, acicular prisms; neutral; inodorous; bitter; pungent; soluble in 375 parts of water at 60°, and in 330 parts at 212° Fahr.; insoluble in ether; does not neutralise the acids, and is destitute of basic properties. It is distinguished from morphia
by its easier fusibility (190°), and by forming a blue liquid with the dilute mineral acids, which on gradual dilution changes to violet and rose red, and ultimately becomes colourless. It does not strike a blue colour with ferric chloride, like morphia, but forms a blue compound with iodine, which is decomposed by boiling water. It appears to be inert, and has not been applied to any useful purpose.
NAR′COTICS. Syn. Stupefacients; Narcotica, Stupefacientia, L. Medicines which produce drowsiness, sleep, and stupor. In small doses, narcotics mostly act as stimulants, but in larger ones they produce calmness of mind, drowsiness, and torpor; and in poisonous doses, delirium, coma, and death. The general objects in the administration of these agents are the production of sleep and the alleviation of pain. Their action is modified to a greater degree by idiosyncrasy and habit than that of, perhaps, any other class of medicines. Hence the care necessary in their administration. Alcohol, camphor, chloroform, chloral hydrate, ether, foxglove, hemlock, henbane, morphia, opium, and tobacco, are narcotics.
NAR′COTINA. C22H23NO7. Syn. Narcotine, L.; Sel d’opium, Matière de Derosne, Fr. A peculiar crystalline substance, found by Derosne in opium, and on which its stimulant property was at first supposed to depend.
Prep. 1. From opium exhausted of soluble matter by cold water, by treating it with water acidulated with acetic or hydrochloric acid, filtering, neutralising, with ammonia, and dissolving the washed precipitate in boiling alcohol; the narcotine is deposited as the liquid cools, and may be purified by solution in ether.