Syn. Blue Vitriol.

See volume i. page 406, for a general account of this medicine. As an emetic, it possesses properties closely analogous to those of sulphate of zinc, so that what has been said above of the latter, may be said of this also, with the exception, that, if there is any difference between them, the salt of copper is still more prompt, more energetic, and less disposed to nauseate than that of zinc. it is, moreover, more dangerous, being much more irritant and corrosive.

Like sulphate of zinc, too, it is used chiefly in cases of narcotic poisoning and pseudomembranous croup. in its application to the former purpose, the caution is still more necessary, to avoid a too frequent repetition of the dose; as, if it accumulate in the stomach, and remain long without vomiting, though it may give no signs of action during the state of insensibility, yet, upon the occurrence of reaction, violent inflammation may ensue, even should the medicine, in the mean time, have been discharged. The dose should not, I think, be repeated more than once; and it would be best to administer it in no case until milder emetics had been tried without effect.

In pseudomembranous croup, sulphate of copper has been considerably used, since originally recommended by Dr. Hoffman, of Darmstadt, in 1821, and more recently by Dr. Droste, of Germany, who had extraordinary success with it in the treatment of the disease. it acts almost immediately, and, by the violence of the vomiting, was thought by Droste to cause a separation and discharge of the false membrane more efficiently than any other emetic. The dose for a child from one to two years of age is a grain; from two to four years, two grains; and from the latter age to ten, about three grains. if complete relief is not obtained by the first dose, from one-quarter to one-half of a grain is, according to Dr. Droste, to be given every two hours; and of these smaller doses more than three or four are seldom required. (See Am. Journ. of Med. Sci., xvii. 231.) There can be little doubt that this medicine will, like tartar emetic or ipecacuanha, cure nearly all the cases of ordinary spasmodic or catarrhal croup; and such, probably, were most of the cases of the disease treated by Droste, all of which recovered. But, in the pseudomembranous croup, it very often fails. in one instance, in which I used it, a tube of false membrane, two inches or more in length, was discharged; yet the child nevertheless died of the same affection, extending deeply into the bronchial tubes; and it is the tendency, I believe, to this extension, which renders the disease so terribly fatal; even tracheotomy offering little chance of relief under such circumstances.

The dose of sulphate of copper, under ordinary circumstances, is two or three grains; in cases of narcotic poisoning, from five to fifteen grains.