GOLD. —Medical Properties.

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the button, of mixed gold and silver as drawn directfrom the furnace, must be due to silver originallypresent in the alloy.

The silver contained in the solution of its nitrate,resulting from the common process of parting,may readily be recovered by adding an excessof chloride of sodium, which will throw downthe whole of the silver as white insoluble chloride.This precipitate, which speedily becomes slate-coloured on exposure to light, is collected and putinto a vessel containing water acidulated with hydro-chloric acid; some zinc or iron is introduced, andthe silver is rapidly restored to its metallic state, inthe form of a dark-grey powder.

The supernatant liquid having been decanted, thisfine metal is washed with dilute hydrochloric or sul-phuric acid in order to remove traces of iron or zinc,but as the removal of the former of these metals maybe effected more perfectly, it is now always used inpreference to the latter; after washing with water,and drying, the silver is fused in a crucible with theaddition of a little carbonate of soda or nitre, andcast into bars.

Physiological Effects, &c. —Gold, says Pereira,like other metals, has been frequently supposedto be inert while it retains its metallic condition,but in this, as well as in some other instances,the accuracy of the assumption has been denied.Both Chrestien and Niel, as well as other writers,assert that finely-divided metallic gold —-pufois auri —produces the same constitutional effects as thosecaused by the various preparations of this metal,but in a milder degree, while it excites little or noirritation. It is said to promote the secretions of theskin, kidneys, and salivary glands.

It has been employed as an antivenereal and anti-scrofulous remedy by Chrestien, Kiel, and others,with considerable success. It is said to be prefer-able to the other preparations of this metal indelicate and nervous subjects, females and infants.Gold-leaf —aurum folialum seu lamdlatum —is usedby dentists for filling decayed teeth, and wasformerly employed by apothecaries for coveringpills —ad inaurandas seu obducendas piMas. Silver-leaf now takes its place. It has been administeredinternally in doses of from a quarter of a grain to agrain three or four times a day. Chrestien usedit by way of friction on the tongue and gums. Nielemployed it endermically—that is, applied it to theskin deprived of the epidermis—in the form of oint-ment composed of 1 grain of gold and 30 grainsof lard.

Teroxide of gold is sometimes used internally, invenereal and scrofulous diseases, in doses of fromone-tenth of a grain to a grain, made into the formof pills with mezereum.

The terehloride of gold, the preparation of whichis described at page 109, acts, according to Orfila,as a corrosive when introduced into the stomachof animals, but with less energy than the chloride ofmercury, and destroys them by the inflammation ofthe coats of the alimentary canal which it sets up.

On man its effects are analogous to those of

chloride of mercury. In small doses it acts, accordingto Chrestien, more energetically as a stimulant,though less powerfully as a sialogogue, than cor-rosive sublimate. It promotes the secretions of theskin, the salivary glands, and the kidneys. Takento the extent of one-tenth of a grain daily, it hasoccasioned violent fever. Collerier lias seen one-fifteenth of a grain excite, at the second dose,gastric irritation, dryness of the tongue, redness ofthe throat, colic, and diarrhoea. When it promotesthe. secretion of saliva, it does not, as mercury,affect the teeth and gums. Magendie has seenviolent gastritis, accompanied by nervous symptoms—cramps and pains in the limbs, agitation and lossof sleep—and afterwards great heat of skin andobstinate sleeplessness. In large doses, it wouldprobably occasion symptoms similar to those pro-duced by the use of poisonous doses of chloride ofmercury.

It has been employed, with variable success, as asubstitute for mercury in the secondary symptomsof syphilis. A more extended experience is, how-ever, necessary to enable one to speak of its remedialpowers with confidence. In the hands of Chrestien,Niel, Collerier, Legrand, and others, it hasproved most successful.

It has also been used in scrofulous affections,bronchocele, chronic skin diseases, scirrhous tumours,&c. Doportal cured with it a case of obstinateulceration of the face, regarded by him as cancerous,and which had resisted all the ordinary methods.

Legrand has used terehloride of gold, acidifiedwith nitric acid, as a caustic in syphilitic, scrofulous,and scorbutic ulcers, cancerous growths, and ulcer-ations of the neck of the uterus.

Internally, it has been given in doses of one-twentieth of a grain, made into pills with starch.But as organic matters decompose it, it is better touse it in distilled water, or to apply it by frictionto the mouth, in quantities of from one-sixteenth toone-sixth of a grain.

The whites and yolks of eggs, milk, and a mixtureof wheat-flour, oatmeal, or barley, and water, are, asin the case of chloride of mercury, antidotes for anoverdose of this auric compound.

It is surprising that the above are so little used inmedicine. Surely, if physicians would only dailyexperiment on the action of the different metals andtheir compounds upon the system, they might soondiscover some very valuable specifics.

Statistics. —Gold and silver are frequently con-founded in statistical returns under the commondesignation of the precious metals; and even wherethe two are classed separately, it is still desirable toplace them in juxtaposition, since much of the interestattached to the subject is derived from the relationwhich they bear to each other. In stating the mostimportant facts connected with the statistics of goldmost of the corresponding figures relating to silverwill also be given, which will not only save therepetition of a number of tables nearly similar,but will furnish the reader with a clearer and moresatisfactory view of the subject, than if the returns