water to drink after the administration of a dose of calomel, I can safely say, that never yet have I seen any evil effect result from the use of it; on the contrary, I have always considered the use of it beneficial.

As a Eutrophic, mercury is useful in many obstinate cutaneous affections. By the use of the bi-chloride in small and oft-repeated doses, the eruptions will frequently disappear, and the parts be restored to a perfectly healthy condition.

"In congestion, and consequent remora of the circulation, so frequent in advanced stages of fever, in the gastro mucus membrane substances fail to produce their effect when applied to their surface. Patients in this state cannot be salivated. The mercurial medicines remain upon the surface to which they were applied."

Mercury has been found useful in destroying certain exostosis which are a true hypertrophy of the osseous tissue. The general therapeutical effect of mercury is to superinduce a new action in the secretory system, in which it always appears to act as a physical excitant.

In consequence of the many peculiar and physical properties possessed by mercury, it has excited the curiosity and attention of the medical profession for ages, and still continues to do so. With oxygen, it forms two oxides, one red and the other a gray, both of which are salifiable. "The red is the most permanent, and should be regarded as the protoxide in place of the gray, to which the name has been applied." The true constitution of these oxides are not, in the present state of our knowledge, correctly understood; nor will they be, until the isomorphous relations connecting mercury and other elements are better comprehended.

The protoxide of mercury (Hg O.) is obtained from calomel digested in a solution of caustic alkali. It is ashcolored, and its composition is fully exemplified in this formula: Hg. Cl. and Ca. O-Hg. O (the protochloride) and Ca. Cl. given off. This preparation is not much used. The bichloride of mercury or corrosive sublimate, (Hg. Cl2)

is a very active corrosive poison, and is obtained by boiling mercury with sulphuric acid until a dry, white mass is left. Rub with this the chloride of sodium and then sublime. This bichloride forms a white, dense, transparent, crystalline mass, the melting point of which is 509 degrees. It is dissolvable in ether or alcohol, and also in sixteen parts of cold, or three parts of hot water. The best antidote to this poison is albumen-the white of one egg being able to counteract the effect of four grains of corrosive sublimate.

The protochloride of mercury, (Hydrargyrum Chloride Mite Hg. Cl.) may be made in a great variety of ways, one of which I give: HgO. SO.3 and Na. Cl=Hg. Cl. the calomel and NaO. SO3 the sulphate of soda is given off.

The tests of the presence of mercury are both general and special. In making a post-mortem examination it is sometimes necessary for us to examine the contents of the stomach of the subject, which should be dissolved, no matter how.

The best tests for corrosive sublimate are as follows: A bright copper plate dipped in a solution will be covered with a white metallic coat; the protochloride of tin will give us a black precipitate; the iodide of potassium will yield yellow precipitate; and ammonia a white precipitate, when added to a solution containing the bichloride of mercury. All these are positive proofs of its presence.

Sulphuret of mercury, (Hg. S.) commonly called vermillion, when subjected to a high degree of heat, will be converted into a metallic state. It is of a very beautiful red color, and resists the action of all the acids, even nitric acid, and the caustic alkalies; being attacked only by the Aqua Regia.

Hydrargyrum cum Creta (mercury with chalk), is an excellent preparation for increasing the biliary secretions in children, in cases of cholera, and in some cutaneous diseases.

The Pillulæ Hydrargyri of the USP is a very mild and convenient mercurial, every three grains of which contains one of mercury. When combined with rhubarb or aloes, it may be used with benefit in cases of torpidity of the

bowels. When administered in small doses it is an alterative; when taken in large doses it is a purgative. Sometimes it is used in cases of chronic dysentery; and other inflammations of the mucus membrane, of a chronic character.

Hydrargyrum Oxidum Rubrum (red precipitate), is of a bright red color, with a light cast of orange, and is often adulterated with red lead. This article is used externally only-in the form of a powder or an ointment-to old and indolent ulcers, which it stimulates to take on a healthy action.

Hydrargyri Chloridum Mite (mild chloride of mercury, or calomel). This article was first described therapeutically by Beguin, (of Europe, in sixteen hundred and eight), who called it Draco Mitigatus, in consequence of the bichloride being known to the alchemists under the name of Dragon. By some of the older pharmaceutical chemists calomel was called Aquila Alba, Panacea Mercurialis, and Sublimatum Dulce. It has been often used in combination with opium, (as an anti-syphilitic), when it salivates without purging.

As an Anthelmintic, it exerts no marked salutary effect, unless it be as a purgative. It is used as an alterative in chronic hepatitis, and in various glandular and cutaneous affections, as well as in epilepsy, tetanus and other disorders. In these cases it is generally combined with opium, to prevent its passing off, and in order to secure its full and speedy effect.

The Bichloride of Mercury (Hg. Cl2 corrosive sublimate) when pure, is entirely volatile; if not so, it must contain some impurity. This preparation contains two parts of chlorine to one of mercury. The taste is not only metallic, but nauseous, acrid and astringent. It is obtained in imperfectly crystallized, white, semi-transparent masses, and is quite soluble in twenty parts of cold water. The addition of salt, however, greatly increases its solubility. Boiling water will take up one-third of its weight.

This preparation, if used incautiously, is a dangerous one, being a powerful poison; and is apt to bring on dys

peptic symptoms, diarrhea, &c. These symptoms may be prevented by using opium in combination with it. Formerly, it was much used in the treatment of venereal disease, but is not now often employed. The dose is from the sixteenth to the eighth of a grain. With cinchona, it is sometimes used as an alterative. When applied externally, it is a powerful stimulant; but its solubility permits it to be used in almost any state of dilution. The poisonous effects of this salt are to be seen on animals as well as upon When taken into the system in improper quantities, it corrodes the coats of the stomach, creates inflammation of the lungs, depressed action of the heart, and possibly inflammation of that organ. So says Dr. Christison. Its antidotes are albumen, the gluten of wheat, iron filings and milk. These are the principal, and most to be relied on.

man.

Hydrargyrum Ammoniatum (white precipitate), is a neat preparation, and is useful, externally, for the destruction of vermin; which it does without much irritation of the skin. In the form of an ointment it is used for the same purposes, and for the cure of the itch, and herpetic eruptions.

Iodide of Mercury (protiodide). This must be kept in well-stopped bottles, excluded from the light. It is of a yellow color, which will sublime in red crystals upon the application of heat; and light being admitted to them they will blacken. The biniodide differs from the protiodide by having, as its name implies, double the amount of iodine contained in it, to the same amount of mercury, as the protiodide. Both of these preparations act as powerful alteratives; and are used in the treatment of scrofula, indolent tumors, and in the cure of syphilis in persons of a scrofulous diathesis. The dose of these medicines is from the one-tenth to the one-half of a grain-given either in pill or solution, two or three times a day. When used as an ointment, it is applied to ulcers, tumors, and swelled joints. It promotes the action of the absorbent vessels of the parts. It is sometimes used as a stimulant to the nerves, on the opthalmic branch of the fifth for amurosis.

The ointment of the Nitrate of Mercury is used effica

ciously in many cutaneous diseases. The mercurial plaster is applied to glandular swellings and venereal buboes, and also over the region of the liver in cases of hepatic derangement.

The preparations of mercury already referred to, although not all, are among the principal and most important of those used in the practice of medicine, and should be thoroughly understood by every practitioner, before he has recourse to them in the treatment of disease.

The treatment of persons poisoned by the use of mercurial preparations, will vary with the cause and symptoms of the patient. The principal antidotes have been already referred to. The treatment of salivation, when very profuse, is quite easy-cool air, nourishing food and mild aperients being the leading remedies. Frequent doses of tartar emetic, so as to act upon the skin, have been recommended by Dr. Findlay, of Ohio; and the acetate of lead, in large doses, has been found to be of great benefit by Dr. Christison and Mr. Daniel.

The discovery of this article as a remedial agent is to be regarded as one of the greatest discoveries in medical science. It is, indeed, one of the Samsons of our Pharmacopoeia, from the proper use of which, happy results will always be obtained, in the hands of the intelligent, prudent and careful physician, who loves his profession and takes an interest in the well-being of his patients.

Mercury, and all its preparations, are, indeed, valuable remedies, placed in the hands of the physician for the purpose of enabling him the better to contend against the many painful diseases to which mankind are subject. If used properly, it exerts upon the system an excellent salutary effect; but if it is used improperly or incautiously, and no attention be paid to the signs of the constitutional effects of the medicine, the most alarming symptoms may exhibit themselves. In many cases, in fact, mercury has to bear the blame of having done mischief, when the physician, on account of either carelessness or ignorance, is the one upon whom the ignominy should rest.