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It is a triple sali, and is thus Danaen Dr the reason gi Venunder the head Soda tartarigata. No preparation is of greator importance, or has been subjected to more VarietieS, as maybe seen in the Essay upon it in Berginan's opuscula, whichveli deserves attention ; so much in deed do es it differ indifferent Pharmacopoeias, that Geosfroy found the proportionos oxyd os antimony to vary Dom .lo to .25. VariOUS modes have been employed for iis preparation: the Pharmacopoeia of lI87 used as iis base the Crocus antimonii; othersilie Antimonium vitrifactum; others again the Precipitate froni iis muriate called Pulvis Algarothi, and as approXimat-ing thereto the former edition prepared an odiyd from a mixture os muriatic and nitric acid ; to this howevor it has been justly objected that it cannot be prepared upon the large Scale, and in ivide-mouthed vesseis; and a New formula haS, after numerous triais, been adopted, whicli is due to Mr. Hume of Long Acre, to Whose practical si ill it is right to acknowledge great obligation. It is necessary that the whole Ofthe Supertartrate os potass should be combine d witti theoXyd, and there re that there should bo a tali suffciencyof the lalter, otherwise the sirst crystals, as it cools, will be of the Supertartrate only ; Whilst, on the other hand, is a superabundarace of oxyd os antimony be used it will remalia Dponthe filior, and not influence the crystals; the former incon-
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venierace theres ore is e specialty to be avoided, and for that PUTPOse more oXyd than may be strictly necessary is directed.
The evaporatiora must not be carried too far, as there appears to be sonae tartrate Os potass in the solution, Whose crystalSwill in that case be mixed with the triple sali. The crystalsought always to be formed, for it is ora ly When they are that the proportions of the sali cara be considered as preci Se. Afier the formation of the crystais, is the liquor be evaporat ed to dryness, it Will osten yield a transparent brownishyellow mass, which looks like resin, and whicli I have nevereXamined accurately, sarther than to assure myself that it contained antimony. The more perfect of them Will be regular Dur-si ded, or triangular pyramids, or eight-si ded; theyWill be come opaque on exposure to air, but Will uot crumbieli e the essiorescent salis. It has been usefultu stated, that
the purity of the crystals should be tested by dropping sonae
into a solution os sulphuret os potass, When a copiOUS Orange-
coloured precipitate ought to forna, or is the salt be in poWder, that iis perfeci solubility in Water sttollit be tried, to asincertain Whether it be mixed with any of the stightly solubie
supertartrate Os potass. Very disterent statements are maderes pecting their solubility. Fourcroy says, that one part issolubio in SO cold and 40 boiling Water; and Duncan, thatone part is solubie in I 5 of water at 60', and in I at 212'. Thera ard gives iis constituent paris as acid 35, i Oxyd 39, 3, PotaSS 16, 7, Water 8, 3, or tartrate os antimony 56, 3, tartrate os potass 35,ψ, water 8, 3. It Should be remembered in pre- scription, that this sali is decomposed by the alhaline earths,alhalies, their sub carbonates and hydrosulphureis, and also bydecoctions os bit ter and astringent planis, Which lalter yielda yello visti red precipitate, Whicli is not emetic ; and that Berthollet, ii pon this principie, proposes decoction os barkto be USed as an antidote, When the sali has been taken insuch quantities as to do injury.
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SOLUTION OF TARTARIZED ANT IMONY.
Vinum antimonii fartarietati, P. L. 178I.
The Vinum Antimonii of the Pharmacopoeia of 1787 hasbeen omitted in the present one, on account of iis uncertainty, for it depended for iis strength upon the quantity of acid contained in the wine used, and this is alWays very variable. The same objection also held in a stili higher degree against the Wine prepared Dom metallic antimony, Which Was preferred by Dr. HuXham. The preparation here given, althoughit is analogous to the Vinum Antimonii tartarigati, yet differs Bom it in the proportion of the sali dissolved; each fluid-Οunce of the lalter contained Dur gratias of tartariged anti-mony, Which in the present preparation has been lowered tohalf the quantity or two gratias in each fluidounce. Theobject os ali these solutions being to afford a ready mode OfdiViding active substances into minute quantities for internaluse, it has been thought that the proportions noW giVen
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Would be more convenient than the former for that pur-POSe, Since A gr. is osten used as a diaphoretic Which wouldhe contained in 15 mininas of such a solution, and might thenbe readily measured and administered. Solutions os metallicstilis ought not to be kept for any tength of time, as it mayhe objected to them that they form precipitates and consequently become wenker.
Puhis Antimonialis, P. L. 178I.
I his preparation was introduced into the Pharmacopoeia os II 87 as a substitute sor a medicine os extensive celebrity,
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Dr. James's po er; to whicli, hoWever, the present formmore nearly assimilates in iis dose, and it is also renderenmore manageable in iis administration, by the reduction ofine proportion os antimony to one half. In the applicationos heat in this process, great care is neceSSary, and the Uncertainty of uniformity in this respect, has, in other instances, induced the College rather to substitute precipitations. It has however been judged right to preserve thepresent form, in preference to the precipitated one given byΜr. Chenevix, Phil. Trans.) with an espectat caution, that the heat may be managed as closely as possibie according to the directions, and be by no means continued for a greater tength of time. The following is the receipt for James's Powder, as e X- tracted froni the Records of Chancery. . Tahe antimony, calcine it with a continuat protracted heat in a flat ungi aged earthen vesset, ad ling to it Domtime to time a sussicient quantity of any animal oil and sali, weli dephlegmated; then boli it in meited nitre for a considerable time, and separate the poWder Dom the nitre by dissolving it in Water. Talae quichsiluer, malae an amalgam Willi equat paris of tbe martiat regulus os antimony and pure silver, adding a proportionabie quantity of sal ammoniac. Distit Osf the mercury by a retori into a glass receiVer, thenwith the quicksilver malae a fresti amalgama With the fame ingredients; distit again and repeat this operation nine orten times ; then dissolve this mercury in spirits of nitre, and put it into a glass retori and distit to dryness; calcine thecaput mortuum illi it becomes of a gold colour; burn spiriis of wine u pon it, and heep it for use. The dose of the poWder is uncertain. In generat, thirty gratias of the anti monial powder and one grain of the mercuriat is a moderate
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solve the silver therein on a sand bath; thenitici ease the heat gradually that the nitrate os silver may be dried. Μolt the sali in a Cruci ble over u sto v sire, untii the waterbeing evaporaled, it censes to boli: thenpour it qui chly into moulds of convenient
Nitric acid dissolves abolit iis Weight os silver, but thereis no objection to a superabundance of acid, as, is it exist in the first, it is driven off in the subsequent paris of the processuebui in the former edition, this was properly stated to be Un- neceSSarily great, and is theresere now diminished. The crucibie in Whicli it is meited should be of close teXture, Or
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be cause the mass swelis and may boii over; and the operatorshould fur ther talae care not to come into contact with the corro Sive Spray Whicli iS thrown up, and care should also betaken that the temperature be not higher at any time than is necessary to the effeci, and that the acid be not de composed
by it. The instant the ebullition ceases, and the substancerematiis at the bottom liquid and smooth like Oil, it should bepoured into moulds Of iron, or pipe-clay greased, after Whichit will, as it seis, assume a greyisti colour and radiated appearance in iis fracture. It is most especially used as a causti for decomposing animal substances, and it is also osten administered internalty as a most poWerfui antispasmodic in Some cases of muscular convulsion. The quantity of such a substance whicli the human stomach Will bear Without injury, affords me an opportunity os observing that the doses of medicines can only be learned by experience, and not inferredfrona calculations, and that Ι have been caresul in many instances, as in the present, to keep below the mark whicti myown experience Would justify, in not stating the maXimum above 5 gr. Ιt dissolves in an equat weight of water at 6O'; the solution is colourless, but is the fused preparation be dissolved, sorne se thin dark silms rem ain. It may be crystal-liged in thin plates. Its taste is bitter and strongly metallicrand it is considered by Proust as an Oxynitrate. The metalis reduced by exposure to a strong light; and, inde ed, it is an observation which may apply forcibly to ali other metallic preparations as Weli as to this, that they should be Eept care-
fully secluded frona light. Although Resned Silser is directed in the Materia Medica,
it may not be superfluous here to repeat, that the puri ty of the metat is necessary to this preparation, and that iis common alloys With copper, as in silver coinage, ought not to be
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REDUCE Oxyd of Arseni C to poWder, thenput it into a Cruci ble, and apply heat so asto sublime it into another cruci ble inverte l
Arsenic is usually mixed with the ores os other metais, and the oxyd os commerce is chiefly separated by sublimationfroni the cobali ores of Saxony. It is seund in the shops sither under the forna of white poWder, or in Shining semi- vitreous lumps, which lalter fati into poWder gradually on exposure to air; the lumps are to be preferred, but as theyare prepared coarsely upon the large scale, it has been judged proper to submit the arsenic to another sublimation, as apharmaceutical process, for the complete separation of anyeXtraneous matters derived frona the original ore. The sublimation may be effected by a heat os about 88 3'. Whiteoxyd os arsenic has a sharp acrid taste, to whicli succeeds aflight sense of smeetness; iis smeli, When subliming, is peculiar, and very like that os garlic; one part dissolves in 80 of Water at 6O', and in 15 of water at 212'; it is solubie also in 80 paris of hol alhohol. From these solutions it may be crystalliged into four-sided crystals. It whitens copper is heated belween two plates of it. Ιt is precipitaled under the
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form os sulphuret, by sulphuret os potass, or sulphuretted hydrogureis ; heated with carbonaceous matter of any sori it is metalliged, and in a heat of 356' sublimes into lamellar metallic plates. It consists of I5,2 metal, and 24, 8 oxygen, accordingio Proust, and as it poSsesses many properties of the acids, ithas been ranked among them by Fourcroy, and called Arse-nious acid. Is it has been taken in to the stomach in quantity sufficient to produce deleterious effecis, the proper Practice seems to be to sileath the stomach from iis contact bymucilages, and at the fame time to endeavour to render itinnocuous by chemicat agenis, of whicli the readiest, and a Very effectual one, is a solution os sulphuret os potass.