The sulphate is the only salt of copper employed medicinally, although other compounds, as well as the metal itself, are introduced into the Pharmacopoeia as tests.

1. Cupri Sulphas

Cupri Sulphas. Sulphate of Copper. CuSO4. 5H1O 5H1O.

Source. - Made by heating Sulphuric Acid with Copper, dissolving the soluble product, evaporating and crystallising.

Characters. - A blue crystalline salt in oblique prisms. Solubility, 1 in 3 of water.

Impurity. - Iron.

Dose. - As an astringent or tonic, 1/4 to 2 gr.; as an emetic, 6 to 10 gr.

From Cupri Sulphas is prepared:

.Sulphate of Copper. Anhydrous. CuSO4. - A yellowish-white powder made by heating sulphate of copper to 400° Fahr. Used in testing. F - 8

Copper wire is used for preparing Spiritus Ętheris Nitrosi.

2. Subacetate of Copper of Commerce. Verdigris. Œrugo. (C2H3O2)2Cu,CuO. In powder, or masses of very minute crystals of a bluish-green colour. Used in chemical testing.

Action And Uses. 1. Immediate Local Action

Externally. - The action of copper differs but little from that of silver and zinc. It does "not affect the unbroken skin, nor is it absorbed by it into the blood. Applied freely to wounds, ulcers, or the delicate surface of exposed mucous membranes, such as the conjunctiva, the sulphate or "blue-stone" is caustic, and is in frequent requisition to destroy warts, chancres and poisoned wounds, and for similar purposes. A swift and slight application of the crystal, or its solution in water, acts so far like nitrate of silver - precipitating the discharges from a mucous or ulcerated surface; coagulating the superficial layers; thus contracting the blood-vessels and arresting discharge. It is used as a stimulant to ulcers; and a solution of 2 to 5 gr. to the oz. may be used as an astringent lotion, or injected into the vagina, rectum, or urethra.

Internally. - The local action of copper on the mouth, beyond its astringent metallic taste, corresponds with that just described. If long administered, it may cause a greenish discoloration of the bases of the teeth (not of the gums) from direct combination with decomposing products there.

Sulphate of copper, in large doses (10 gr.), is not entirely converted into an albuminate in the stomach, but acts on the mucous membrane as an irritant, and causes vomiting. It is a rapid direct emetic, and is suited for administration when the stomach is to be surely and speedily emptied of a narcotic poison, such as opium, or the air-passages evacuated of mucus or false membrane, as in bronchitis and diphtheria, after ipecacuanha has failed. It causes less depression and subsequent nausea than tartar emetic. If sulphate of, copper fail to vomit, it must be evacuated by some other means, otherwise dangerous inflammation may result.

Lastly, copper, sulphate is a valuable antidote to phosphorus, as it is reduced by the metalloid, the copper being deposited upon the phosphorus and rendering it inert. In cases of poisoning by phosphorus, 3 gr. of blue-stone should be given in water every few minutes, until vomiting occurs, whereupon a free saline purgative is to be administered.

In the intestines copper is an astringent in small quantities, an irritant purgative in larger quantities. Small doses, combined usually with opium, are given for some kinds of diarrhoea.

2. Action In The Blood

Given in small doses, copper is absorbed into the blood; but we neither know any effect that it produces here, nor use it in this connection.

3. Specific Action And Uses

The specific action of copper on the tissues is most difficult to evoke, as anyone can testify who has watched a large number of persons working in brass and copper. It is said to weaken the voluntary muscles and heart, and to affect the nutrition of the central nervous system; whence it was formerly used in convulsions and spasmodic diseases, including epilepsy, chorea, and hysteria. This treatment is now almost obsolete. It is believed by some to be a specific astringent to the uterus.

4. Remote Local Action

Copper is chiefly excreted by the liver, that is, leaves the body with the bile and faeces; part is discharged in the urine, and part by the saliva. No special advantage is taken of its ehmination by these channels.