Hydrargyrus purificatus Ph. Lond.

Quicksilver, triturated with powdery or with thick unctuous matters, is gradually divided, and incorporated with them into one uniform compound, in which no particle of the mercury can be distinguished by the eye. It is most difficultly mixed with earthy powders, moft eafily with thick balsams and mucilages.

Killed or extinguished, that is, ground till the mercurial globules disappear, with one twelfth its weight or more of Venice turpentine, or half that quantity of balsam of sulphur, it is mingled with plasters; which, for this purpofe, are to be melted, and taken from the fire, before the mercury is stirred in. The college of London directs the mercury, killed with balsam of sulphur, to be mixed with four times its quantity of the common plaster +, or of gum am-moniacum ‡: that of Edinburgh uses six parts of common plaster, and one each of oil olive and white resin, to three parts of the quick-silver ||. Thefe compositions are applied as resolvents and discutients, against venereal pains, and indurations of the glands; the mercury exerting itself in some degree upon the part, though it is rarely introduced into the blood in such quantity as to affect the mouth. Aftruc observes, that even by covering all the limbs with mercurial plasters, the method once prac-tifed for raising salivations, it was difficult to obtain a complete and effectual ptyalism (a).

Substances of less consistence, as ointments, leave the mercury at more liberty to act; and are generally and deservedly preferred to the plasters, in the intention of topical resolvents, etc. as well as in that of conveying the mercury into the habit. A dram of quicksilver mixed with unguents, well rubbed into the skin, and repeated every day, or rather every other day, generally produces, soon after the third application, and sometimes after the second, appearances of inflammation in the mouth, which are followed by a free and copious ptyalism: those employed in rubbing the ointments on others, have been salivated by the mercury imbibed through the palms. The ptyalism raised by unction is often more effectual, and accompanied with fewer inconveni-encies, than that produced by mercurials taken internally ; which last are apt, in some constitu-tions, to run off by the intestines, without affecting the salival glands; and in others, to affect the mouth so hastily, as to excite a copious salivation without extending their action sufficiently to the remoter parts. The mercurial ointments are commonly prepared, by rubbing the mercury with lard or other fat matters of a due consistence: three parts of hog's lard, and one of mutton suet, make a commodious bails, with which may be mixed one part or more of mercury†. Or the hog's lard may be used in much greater proportion to the fuet, as twenty-three parts of the former to one of the latter, for an equal weight of quicksilver ‡; which may occasionally be let down by adding twice its weight of hog's lard ||. As a good deal of labour is required for thus uniting the quicksilver with simple fats, some are accus-tomed to previously extinguish it with a little turpentine or balsam of sulphur; these additions, however, particularly the turpentines, are, in this form, accompanied with an inconvenience; being apt, by frequent rubbing, to fret the skin.

(a) De morbis venereis, torn. i. lib. ii. cap. 7.

† Emplastr. lithargyri cum hydrar-gyro Ph.

Lond.

‡ Emp. amnion. c. hy-drarg. Ph. Lond.

Emplastr. e hydrarg. five caeruleum Ph. Ed.

† Ung. ex hydrarg. five caeruleura Ph. Ed.

‡ Ung. hy-drargyri fortius and || mitius Ph. Lond.

Mercury is divided also, with different materials, for internal use, and given, as an alterative and as an anthelmintic, from two or three grains to eight or more. Half a dram of quicksilver is ground, for example, with two scruples and a half of prepared chalk. Sometimes also purgative materials are joined: the pills called Bellofte's, are supposed to be a composition of this kind. The Edinburgh and London colleges, in their last dispensatories, have rejected all these compound forms. The former direct only a mass of pills made of quicksilver divided by equal its weight of honey, and afterwards beat up with double the Weight of bread-crum and a sufficient quantity of water. The latter direct the quicksilver to be rubbed with an equal weight of extract of liquorice of the consistence of honey, and made into pills with powder of liquorice.

A treatise has been published by Mr. Plenck of Vienna, recommending a mixture of quicksilver and gum-arabic as preferable to all the other mercurial preparations hitherto known; being in all cases safe, rarely or never producing a salivation, and acting soon on the venereal virus. He directs one dram of purified quicksilver, and two drams of the gum, to be ground together in a stone mortar, adding by degrees half a spoonful of water, till the quicksilver disappears, and the whole becomes a viscid grey mucilage, which happens in a short time: half an ounce of syrup, and eight ounces of a simple water, are then gradually added, and two spoonfuls of the mixture given every morning and evening. Part of the mercury remains suspended in the liquor, part settles to the bottom, but retains so much of the gum as to continue divided and form a grey mucous sedi-ment, which readily unites again with the water on shaking the vessel: if the fluid be separated, and the sediment dried by heat, the mucilage then loses its power, and the mercury runs into globules.

Hydrarg. cum Creta Ph. Lond.

Pil. mercurial. Ph. Ed.

Pil. e hydrar-gyro Ph. Lond.

The author made trial of several other sub-stances, both animal and vegetable, for the extinction of mercury, but found none that answered equally with gum-arabic. The mucus expectorated from the throat extinguished it, and kept it divided after the addition of water; but very little of the mercury remained suspended in the liquor, both the mercury and the mucus subsiding. Saliva had much less effect: yolks of eggs, white of eggs, bile, glue of isinglass, gum-tragacanth, mucilage of quince seeds, clarified honey, simple syrup, either did not extinguish the mercury at all, or suffered it, on dilution with water, to run together again. But thick honey, unclarified, kept it divided; and syrups greatly promoted the effect of gum-arabic.