The pharmacopoeia of the Royal College of Physicians of London, MDCCCIX

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AC IDUM ACETICUM.

Aeestim distillatum. P. L. II 87. P. L. 1 45. P. L. II 2O

Vinegar, Whicli is in France and Italy prepared Dom Wines, and receives iis common name accordingly, is made inthis country, as an article os trade, by a second fermentationos mori or infusion os mali whicli has previously undergone the spirituous sermentation in Open Vesseis, and in a temperature between I 5 and 90 ; and besides the solubie eXtraneous substances which the vegetable matter itself supplies, othersare commonly added by the manufacturer, Such as sulphuricacid and colouring matter. The object of the present processis to separate these, and to obtain the acetic acid os an uniform and sussicient strength. The use of glais vesseis is intended to do aWay the possibility of the solution of eithercopper or lead, to the contact of whicli metals the acid is exposed is prepared in tho ordinary Way ; yet, notWithstand-

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application to the preparation os larger quantities, that thecommon copper still With a peWter Worm, is most frequentlyemployed. In the distillation a greater heat is not to beapplied than is sussicient to Eeep the liquor moderately botling, whicli it begins to do at 2I 29; for is the heat he urgentOO far, or continued too long, it gives to the distilled acid anem pyreumatic smeli and taste Whicli it ought not to possess. The sirst part whicli passes over on distillation is the water, Iess Strongly impregnated With acid ; and, in order that themore acid pari Whicli subsequently folloWs may be Stronger, the first one-eighth, although it contains sonae portion ofacid, is directed to be thrown aWay, and the neXt siX-eighthsWhicli pass, forin the Acelio Acid of the Pharmacopoeia ; theremaining one-eighth in the retori is os a deop reddisti brown

Colour, and containg the saline, colouring, and mucilaginous matters, and the sulphuric acid; some acetic acid also remains, in a more Concentraled state, than that whicli has actuallypassed over ; but the greater heat which would be requirensor iis distillation mouid decompose the vegetable matter Withishicli it is combined, and thus produce a strong emPyreummatic smeli and flavour, like that acetic acid whicli is actuallyobtained in hi glier temperatures by distillation os Wood orother Vegetable substances. On account also of the densityof the liquor Whicli remains in the retori, and is apt to SWellinto large bubbles, and to pass over, it is proper that the bulla of the retort should be comparatively large. Thus preparedit is considered to be sufficiently strong for ali medicat pur' poses; and there re no second process is noW gi Ven, asformerly, for obtaining a stronger acid by the decompositionos any of those salts of whicli it fornas a pari; especialty sinceit has been thought that there is no other difference in thenature of the acid itself prepared in any of these Ways, than that one is in a more concentraled state than the other,

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Others, hoWever, and who seem to be right, suppose that itis not pure wheia thus prepared by distillation, but that some mucilage passes over With, and is present in it, and that wheniis compotand with potass is bolled, it becomes brown, whilstiliat prepared with an acid obtained by the decomposition ofan acetate, remains colourteta. Is the acid be prepared correctly, it will be colourless, and of a gratesul pungent peculiar acid taste. One fluidounce ought to dissolve at least thirteen gratias of carbonate of lime mire Marb .9 Ofthe impurities Which may be suspected, sulphuric acid maybe detected by acetate of barytes, lead by sulphuretted hydrogeia, and copper by ammonia, added so as to superSatUrate the acid Darracq. An. Chim. V. 4 l. 261. B. Higginson Acuous Aciri So. t 786.

Flores Benzdies, P. L. II 8 I. Flores Benzoini, P. L. 1720.

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gentie heat put it into a Pro Per Vesset placed in a sand bath, and by a very genties re sublime the Bengoic BC id.

BenzOIn is a concrete substance, consisting of a peculiar acidmixed with resin, and chemicatly, there re, classes With thebalsams : this acid is called Benzoic, and it is the object of the Present process to Separate it. Chemisis have effected this in various Ways, either by sublimation, which gives beautifulfoliated crystais, but requires to be repeated thrice, and pressed after each sublimation belween bibulous paper, to obtain them white and Dee Dom any adherent essentiat Oil; this Was the process of the last Pharmacopoeia, and is stili

precipitate the acid: or, by simply boiling the Benzoin inwater inhicli dissolves the acid, and as it coois allows it to separate again. Doeux . The two former processes are here combined: firSt, the acid is separated accor ling to Scheele's method, this consisis in forming a benZoate of lime, and add-ing to the solution thereos muriatic acid, whicli precipitates the benZoic, While the ne N compound muriate of lime re-

mains dissolved; secondiy, this precipitate is subjected toone sublimation which gives iis usual foliat ed crystalline appearance. The Edinburgh Pharmacopoeia, follo ing Gren, formS a benZOate of soda, precipitates the acid by sulphuricacid, and afterwards crystalliges it by Solution in hol Water, Whicli dissolves a larger quantity than cold. The Dublinstill retalias the method by sublimation. Μr. Brande obtain-

ω, by folloWing this process of the Pharmacopoeia, stom One

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Mapound of benetoin, IJ 63 2B I9gr. of the acid Nichiau es Durnal, X. 88. Whicli is to that obtained by the former pro-CesS, about as 45 to 48. Benzoic acie has a Strong, pungent, aromatic, peculiarodour. Iis crystals are ductile, not pulverigable ; it sublimes in a moderate heat, forming a White, irritating smolae. It is solubie in about 24 times iis weight of boiling mater, Whichas it coois precipitates ths of What it had previolasty dissolved. It is solubie in athohol. It may be crystallized by solution in botling water, as by dissolving an ounce in a piniand a half of water, and afterWards allowing the solution tocool; or by sublimation; but as in iis crystalline forsa it is not reducibi e to poWder by mechanical means, it has beensomelimes thought better suiled to the purposes of medicineto keep it in that more divided state in Whicli it is obtained by precipitation alone.

Add the Cholh by smali portions at a timeto the juice, Whilst botling, stiri ing it a sterea cli addition, and then Pour olf the liquor. Wash the Citrato os Lime Whicli rem alias by

then dry it. Add the diluted sulphuric acid

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to the driod poWder, and bo it it for ten minutes: then press it Strongly through a linencioth, and alter Nariis fit ter it through papor.

cister euch solution siter the liquor, boli itdo Wia, and set it hy to crystallige.

The generat use of temon juice for the purposes of medicine, the uncerta in ty of obtaining it Dom the fresti fruit, and the dissiculty of heeping it unchanged, have rendered the

adoption of the present forna expedient, is not absolutely ne ceSSary : and there are also sOme potnts of practice, as in theexhibition os effervescing draughis, Where the diminished bulla of the acid in the forin os crystals and iis Sio er actionas it dissolves Dom a soli 1 state, give it considerable aclvan inge. This Process owes iis origin to Scheele. and the acidhas thias been for sonae years prepared Upon a large Scale and

in a very pure state by Μr. Coxwell, and applied to medicat Use. It depen is upon the formation os an insolubie citrate os lime, whicli is dried and afterwards decomposed by the stronger assini ty of sulphuric acid ; and the delached citricacid rem altas dissolved in the liquor, while the newly-formedinsolubie sulphate of lime precipitates. The liquor Whicli contains the citric acid is evaporated untii the crystals forna as it eools; but Dom the action of the sulphuric acid UPon some adherent mucilaginous matter, the sirst crop of crystals Wili besmali in siete, of a dark brown colour, and impiare ; their CO- O ing matter can only bu separatod by a repetition of the

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solution and crystalligation twice, and , is the crustalg be notthen colourless and weli formed, even a third time. The use of rather more sulphuric acid than is requisite to the decomposition of the citrate is intended for the complete destructiori of the mucilage ser Without this be effected the acidwill not crystallige, though, at the fame time, it certainly also acis iapon a portion Os the citric acid itself. This dissicultyos crystalligation has been urged against the preparation al- together, and a concentrat ed liquor has by some been suggested as more convenient; much of this objection, however, is now removed by practice, and that an elegant and pure article may be prepared Upon a large scale, the great Supplywhich Μr. Coxweli is enabled to malae sum ciently proves. of the crystalliged acid, one ounce dissolved in orae pint of water is equat in strength to one pint of common lemon juice. An equat portion of the crystals is more than sum cient forthe saturation Os one os subcarbonate os potass, but there is generalty no objection to sonae predominance of acid in iis common admini Stration as a Saline draught. According to

require for their Saturation os carbonate os potass 6l, of carbonate of Soda 42, of carbonate os ammonia 44, and of carbonate os magnesia 4O. Os course, the solution in Water has only the acidity of temon juice, not that flavour Whicli dependS Upon the admiXture of iis essentiat Oil, and whicli forsonae Purposes may be a USesul addition. The crystals are rhomboidal prisms, whose fides incline to each other atangies of 12O' and 6OR, terminating at each end by Dur trapezoidat faces whicli include the solid an gles. They are notaltered by eXposure to air. Water at 212' dissolves twice iis

Weight, I A paris of cold water dissolve IO0 paris. It Would be advantageous is the citrate of lime could bemade and imported as weli as the fruit iis eis; for the greater perfection of the fruit in Warmer climates, the quantity Ofac id they yield, and the sinali comparative space whicli the

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lis present price Very considerably. It may be and has been attempted to substitute for it the chea per tartarous acid, butthis may be detected is to a solution of the lalter a solution oflari rate os potass be ad ded, for an in Sol abie supertar trate os potass will then be formod and precipitate in granular crystals. This preparation, properly made, oKeS non e of iis acidity to adherent sulphuric acid; is it cloes, the precipitate yielded by a s mali addition os solution os acetate os lead, Will, as sulphate os lead , he insolubie in acetic acid, while citrate of te ad will be entirely solubie in the Same menStruUm. It may farther be observed, that although the process heregiven does generalty answer, and is common ly emplOyed, yet, that as temon juice somelimes varies in the proportion os acidit contains, it may occasionalty require some modification of the quantity of chath to be added in the sirst instance, and of sulphuric acid in the second. Three ounces of chath WillCOmmonly Saturate 3s pinis of juice, and 27 fluido unces of dilute sulphuric acid will be requisite for iis decomposition. Proust frates cyourn. Pos. 52. that II paris of citrate oflime require 2O paris of sulphuric acid os a Sp. gr. I, Io forthis purPOSe.

Acidum Muriaticum, P. L. II 87. Spiritus Salis marini Glauberi, P. L. t 745. Spiritus Salis, P. L. II 2O.

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having luted on the retori, disti l the muriatio ac id into it by the hoat os a sand bath gra

du atly rai sed to re in CS The specific gravi ty of muriatio acid is tolliat of V ater as 1, 160 to 1,OGO, and a fluido unce diluted with water ought to dissolveos a lum se of lime-stone immersed therein, two hundred and tWenty grain S.

This process differs Dom the former in some practicalpoinis. The proportion os sulphuric acid requisite for thecomplete decomposition of the sali is as 3 to 4, according to Vauquelin s Experiments; but objections having been rat sed to the proportions, further experiments have been instituted, and the present have been found to be correct. The result of the fame experiment has been the change of the standaruspecific gravi ty Whicli ought probably to be a fraction less), and of the quantity of carbonate of lime dissolved thereby;

and as the last portions os muriatic acid adhere more Strongly, so do they require for their delachment that the temperatureshould be considerably increased. Is sulphuric acid, undi-luted, be added to muriate of soda, there is an immediate and Unmanagable eXtrication os muriatic acid gas, and to preventiliis, a dilution of the sulphuric acid with one third of water, allowing such mixture to remain illi iis increaSed temperatur e