MERCURY OR QUICKSILVER.

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few drachms of liquid mercury, as a prophylactic for itch and vermin(Richter, Ausf uhr. Arzneim. Supplem. Bd. 615).

The injurious effects of mercurial vapours, when inhaled or otherwiseapplied to the body, have been long known. They are observed in watergilders, looking-glass silverers, barometer-makers, workmen employed inquicksilver mines, and in others exposed to mercurial emanations. Inmost instances an affection of the nervous system is brought on, andwhich is indicated by the shaking palsy or tremblement mercuriel (tremormercurialis), \\ liich is sometimes attended with stammering ( psellismusmetallicus), vertigo, loss of memory, and other cerebral disorders, whichfrequently terminate fatally. The first symptom of shaking palsy is un-steadiness of the arm, succeeded by a kind of quivering of the muscles,which increases until the movements become of a convulsive character.In all the cases (about five or six in number) which have fallen under mynotice, the shaking ceased during sleep. I have not seen the least benefitobtained by remedial means, although various modes of treatment weretried. This is not in accordance with the experience of Dr Christison,who says the tremors “ are cured easily though slowly.” If the individualcontinue his business, other more dangerous symptoms come on, such asdelirium or epilepsy, or apoplexy ( apoplexia mercurialis) ; and ultimatelydeath takes place.

In some instances salivation, ulceration of the mouth, and haemoptysis,are produced by the vapour of mercury. The following remarkable caseis an instance in point. In 1810, the Triumph man-of-war, and Phippsschooner, received on board several tons of quicksilver, saved from thewreck of a vessel near Cadiz . In consequence of the rotting of the bagsthe mercury escaped, and the whole of the crews became more or lessaffected. In the space of three weeks 200 men were salivated, two died,and all the animals, cats, dogs, sheep, goats, fowls, a canary bird,—nay,even the rats, mice, and cock-roaches, were destroyed (Ed. Med. andSurg. Journ. xxvi. 29).

As metallic mercury in the liquid state is not active, it has been thoughtthat mercurial vapour must also be inactive. Thus Dr. Christison thinksthat the activity of the emanations arises from the oxidation of the metalbefore it is inhaled. I believe, however, with Buchner (Toxicologie ),Orfila ( Toxicol. Gen), and others, that metallic mercury, in the finelydivided state in which it must exist as vapour, is itself poisonous.

2. Of Mercurial Compounds. —Probably all the mercurial com-pounds are more or less noxious. The only doubtful exception to this isin the case of the sulphurets of this metal, which, according to Orfila{Arch. Gen. de Med. xix. 330), are inert.

(a.) Local effects. —For the most part, the local action of the mercu-rial compounds may be regarded as alterative, and more or less irritant.Many of the preparations (as the bichloide, the nitrates, &c.) are energeticcaustics. The protoxide and protochloride (calomel) are very slightlyirritant only: indeed, Mr. Annesley ( Diseases of India ) asserts, from hisexperiments on dogs, and his experience with it in the human subject,that the latter substance is the reverse of an irritant; in other words,that when applied to the gastro-intestinal membrane it diminishes itsvascularity. But I suspect some error of observation here.

(, b.) Remote effects. —In small and repeated doses, the first obviouseffect of mercurials is an increased activity in the secreting and exhaling