Origin

Sulphate of copper exists in solution in the water running from copper mines, from which it is obtained by evaporation and crystallization. But it is more frequently prepared artificially; and the method usually employed in this country is by the direct action of sulphuric acid on copper or its oxide.

Composition

It consists of one equivalent of oxide of copper, one of sulphuric acid, and five of water of crystallization.

Properties

Sulphate of copper is in fine, large, deep-blue, transparent crystals, inodorous, of a strong, harsh, styptic, metallic, and very disagreeable taste, very soluble in water, and insoluble in alcohol. It is slightly efflorescent on exposure. By heat it melts, and loses its water of crystallization, becoming white and opaque; and by an intense heat is decomposed. On the addition of ammonia to its solution, a precipitate is first thrown down, which is dissolved by a further addition of the ammonia, with the production of a beautiful deep azure-blue colour.

Incompatibles. The fixed alkalies and their carbonates, the alkaline earths, the soluble salts of lead, lime, and baryta, acetate of iron, bichloride of mercury, nitrate of silver, borax, tannic acid, and the astringent vegetable substances containing it, yield precipitates with the solution of sulphate of copper, and are therefore incompatible in prescription.

Effects on the System

The effects of this salt are those already described of the preparations of copper in general, with the addition of astringency, in which it much exceeds the others. In short terms, it may be said, in relation to its action on the alimentary canal, to be tonic, astringent, powerfully emetic, highly irritant, and corrosive, according to the quantity swallowed; in relation to its effects upon the system, to be in medicinal doses tonic to the nervous centres, and in excessive doses poisonous by an overwhelming influence upon those centres. Death, with coma and convulsions, has resulted from two drachms of it swallowed. Besides albumen, magnesia has been recommended as specially useful in poisoning by the sulphate.

Therapeutic Application

Sulphate of copper is thought to have been employed as a medicine by the ancients. In regard to its emetic operation, I shall treat of it under the emetics, and as an external remedy, in which capacity it is much used, under the escharoties. It is here considered solely in reference to its tonic, astringent, and alterative action on the stomach and bowels, and its general influence on the system.

1. It is seldom employed for its tonic action on the stomach; but has been highly recommended in chronic diarrhoea and dysentery from a supposed astringent effect. In certain cases of this kind, it is certainly an admirable remedy. No doubt its astringency renders it useful in some of these cases; but I ascribe its efficacy chiefly to a stimulant and alterative influence upon the ulcerated surfaces, similar to that which it exerts upon old and indolent ulcers externally. It has the great advantage, in intestinal affections of this kind, over nitrate of silver, that it may pass un-decomposed through the stomach into the bowels, and thus come into contact with the ulcers. The particular condition in which I have found it specially useful, and in which, so far as my experience has gone, it is equalled by no other remedy, is a kind of chronic enteritis, attended with diarrhoea, distressing pains in a particular part of the abdomen, with or without tenderness on pressure, emaciation, great depression of spirits, a pulse often, though not necessarily frequent, and a moist tongue. In such cases, I have been disposed to ascribe the obstinacy which they often exhibit, and sometimes in an extraordinary degree, to the existence, within a comparatively small extent of the bowels, of a chronic, indolent ulceration, which requires a strongly excitant and alterative impression to enable it to take on a healing tendency. I have seen them, after being treated by a diversity of remedies, opiates, astringents, etc., and lingering month after month, without permanent relief, yield most happily to the persevering use of this remedy, combined with a little opium to render it less offensive to the stomach. A beneficial change is usually experienced in a few days, and afterwards regularly advances to a cure. The only adjuvants which have seemed to me advisable, besides the small proportion of opium, arc a diet exclusively of milk and farinaceous substances, and the daily use of the hot salt bath. In somewhat larger doses than are necessary in the affection just mentioned, I have no doubt that the remedy would prove highly useful also in certain obstinate cases of chronic dysentery, with ulceration of the large intestines. In the former affection, one-quarter of a grain of the sulphate, with the same quantity of opium, or even less, may be given four times a day, and gradually increased, if necessary, till the stomach is disturbed; in the latter, one-half a grain may form the commencing dose, to be similarly increased. The necessity of the larger dose in the dysenteric affection is that, the seat of ulceration being lower in the bowels, the medicine will have been to a greater degree diminished by absorption before reaching it. Dr. Pereira states that he has, in an old dysenteric case, increased the dose to six grains three times a day, and continued this for several weeks, with no other obvious effect than slight nausea, and amelioration of the disease. (Mat. Med., 3d ed., p. 802).

2. For its effects on the nervous system, sulphate of copper has been employed in epilepsy, hysteria, and other spasmodic, convulsive, or nervous affections; but for these purposes it is generally less esteemed than the ammoniated copper, to which the reader is referred. It has also been recommended in intermittents, and might a priori be deemed useful in these complaints, from its corroborative influence upon the nervous centres, rendering them, like quinia. insensible to the irritant impressions which give rise to the paroxysms. Though much less efficient than quinia, it might be used as a substitute for that remedy when circumstances prevent or forbid its use; and I have occasionally employed it as an adjuvant in obstinate cases.*

Besides the diseases mentioned, sulphate of copper has been recommended in dropsy, worms, chronic catarrh with excessive secretion of mucus, and catarrh of the bladder; but I have had no experience with it in these affections, and should have little faith in its efficacy.

* The prescription I have employed is as follows. Take of sulphate of copper one grain, sulphate of quinia eight grains, opium one grain. Form with syrup of gum arabic into a mass, to be divided into four pills. One to be taken four times a day.

Administration

The dose of sulphate of copper, to begin with, is one-quarter of a grain, three or four times a day, which may be gradually increased, if the stomach will bear it well, to two grains. In doses of from three to five grains, it would be apt to vomit. It is most conveniently given in the form of pill, which may be made with crumb of bread, or with a mixture of gum and syrup.