Poisoning with the salts of copper is of comparatively rare occurrence; when it happens, it is generally the result of accident. The metal itself is not poisonous, but the action of the gastric juice may produce a very deleterious salt. Copper coins, when swallowed, sometimes on this account prove mischievous; though usually any ill effects which ensue are due to their mechanical action. Salts of copper have been accidentally introduced into the system by means of food which has been cooked in copper saucers. The most important substances of this class to the toxicologist are the following:

Sulphate of Copper (Blue Vitriol).—Blue-stone is met with in large crystals, which are very soluble in water and possess an acrid metallic taste. In doses of half an ounce it acts as a powerful irritant. It has been administered to procure abortion. In the case of a child sixteen months old, who sucked some pieces of blue-stone with which she was playing, death occurred in four hours.

Subacetate of Copper (Verdigris).—This preparation is met with in masses, or in the form of a greenish powder. It possesses a powerful astringent metallic taste. It is often produced by allowing substances to stand in coppers. It has proved fatal in half ounce doses.

Arsenite of Copper (Mineral Green).—The effects of this salt have been already referred to.

Symptoms.—Pain in the epigastrium, gradually extending over the abdomen, violent vomiting—the vomited matters being of a blue or green color—and diarrhoea, are the symptoms which set in the most speedily. Then there is usually dyspnoea, great depression, coldness of the extremities, headache with giddiness, and slight tetanic convulsions. Sometimes there is suppression of urine. Jaundice very frequently occurs—a symptom the more important, as it is rarely met with in most other forms of poisoning. Occasionally stupor, coma, and paralysis supervene. Should death ensue, it may occur within a few hours, or not for several days.

The salts of copper taken in very small doses, for several days, give rise to a metallic taste in the mouth, thirst, debility, cramps and colicky pains, with symptoms of dysentery. In some instances there has been found retraction of the gums with the formation of a purple line, very distinct from the blue mark due to lead.

Post-mortem Appearances.—Evidences of inflammation are usually found in the stomach and intestines, the mucous membrane being often ulcerated and of a blue-green color. Particles of the poison may sometimes be found adhering to the coats of the bowel. Perforation of the intestines has occurred.

Treatment.—Vomiting sets in spontaneously, and is to be encouraged by the use of warm water. The stomach pump will rarely be needed. The only effectual antidote is albumen. The whites and yolks of several eggs should therefore be given, followed immediately by milk or mucilaginous drinks.

Tests.—Solutions of the sulphate and nitrate of copper are blue; the chloride is green. The salts of copper may be thus identified:

1. A polished knife or needle introduced into the solution is soon covered with a coating of copper.

2. Ammonia produces with a salt of copper a bluish precipitate, readily soluble in excess of ammonia, and forming a splendid blue solution.

3. Ferrocyanide of potassium gives a claret-colored gelatinous precipitate, if the copper be abundant; otherwise the deposit is of a light brown.

4. Sulphuretted hydrogen gas yields a deep-brown precipitate.

5. A few drops of the copper solution are to be placed on platinum foil, and slightly acidulated; on touching the foil, through the solution, with a strip of zinc, metallic copper is deposited on the patinum.