Cupri Sulphas. Sulphate of Copper (purified).

Sulphate of Copper (Anhydrous). Appendix B. Sulphate of copper deprived of its water by heat.

Prep. The native sulphuret of copper, called copper pyrites, when roasted with free access of air, oxidates, and forms the sulphate; the salt thus prepared, however, is very impure, containing, as the ore does, much iron, which, to a great extent, is removed by the process given in the Pharmacopoeia for its purification, namely, by dissolving the sulphate in boiling distilled water, filtering, and setting aside to crystallize. The Anhydrous Sulphate of Copper, deprived of its water by a heat of 400°, (Cu O, So3) is a yellowish white powder, and is used only as a test.

Prop. & Comp. Sulphate of copper forms oblique rhombic azure-blue crystals, with a styptic metallic taste; efflorescing slightly in dry air; soluble in water; and reddening litmus. The aqueous solution gives a white precipitate with chloride of barium insoluble in hydrochloric acid, and a maroon-red precipitate with ferrocyanide of potassium; it is also precipitated by ammonia, but re-dissolved in excess of the re-agent. Composition (Cu O, So3 + 5 HO). A watery solution of the salt, to which twice its volume of the solution of chlorine has been added, when treated with an excess of ammonia, gives a clear sapphire-blue solution (from the formation of the ammonio-chloride), leaving nothing undissolved; this shows the absence of iron.

Therapeutics. Internally, in small doses, it is astringent to the alimentary canal; and after absorption, a tonic to the nervous system. In large doses, a quick and powerful emetic. Externally in powder, or in strong solution, it acts as an escharotic; in a more diluted form as a stimulant and astringent. It is given as an astringent in cases of obstinate diarrhoea and dysentery, also as a tonic in chorea and epilepsy; in some cases of narcotic poisoning, as an emetic. Externally it may be used to excessive granulations or ulcers, or to diminish excessive secretions from mucous membranes, as in ophthalmia, gleet, etc.

Dose. As an astringent or tonic, 1/4 gr. to 2 gr.; as an emetic, 5 gr. to 8 gr. Externally, in substance or in solution, from 1 gr. to 10 gr., or more to the fl. oz.

Adulteration. Sulphate of iron in the commercial salt; sometimes sulphate of zinc is fraudulently added: the iron is detected by ammonia, not redissolving the oxide; zinc, by first precipitating the copper with sulphuretted hydrogen, then, on the addition of ammonia, some of the above gas being in solution, a whitish sulphuret of zinc is thrown down.