Volume 1

The elements of materia medica : comprehending the natural history, preparation, properties, composition, effects and uses of medicines / by Jonathan Pereira, F.R.S. & L.S.

  • Pereira, Jonathan, 1804-1853.
Date:
1839-1840
Catalogue details

Licence: Public Domain Mark

Credit: The elements of materia medica : comprehending the natural history, preparation, properties, composition, effects and uses of medicines / by Jonathan Pereira, F.R.S. & L.S. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    The London Pharmacopoeia professes to follow Soubeiran’s process, r it the formula which is given is much more complex; it is as fol- ws:—Mix three ounces of sesquioxide of iron with half a pint of drochloric acid, and digest for two hours in a sand bath. Add to ese two gallons of water, and set aside for an hour; then pour off the jpematant liquid. Four pints and a half, or as much as may be ! fficient, of solution of potash being added, wash what is precipitated quently with water, and, while moist, boil it with eleven ounces and a If of bitartrate of potash, previously mixed with a gallon of water, the liquor should be acid when tried by litmus, drop into it solution of -squicarbonate of ammonia until it is saturated. Lastly, strain the [uor, and with a gentle heat let it evaporate, so that the salt may main dry. ! The theory of this process is as follows:—By the reaction of sesqui- ide of iron and hydrochloric acid we obtain water and sesquichloride iron (vide p. 541). On the addition of caustic potash, the sesqui- illoride is decomposed, hydrated sesquioxide of iron is precipitated, and loride of potassium is left solution. These changes are illustrated by ee following diagram:— REAGENTS. qq. Potash 144 i]l. Sesquichloride Iron ..164 3 eq. Potassium 3 eq. Oxygen .. i3 eq. Chlorine . >2 eq. Iron ter RESULTS. 3 eq. Chloride Potassium 228 2eq.Sesquiox-l Hydrated Ses- idelron. 801 quioxide of j Iron. When the hydrated sesquioxide of iron is boiled with bitartrate of >’4ash, one equivalent or 40 parts of sesquioxide combine with one uivalent or 66 parts of tartaric acid of the bitartrate of potash, and rrm an equivalent or 106 parts of tartrate of sesquioxide of iron, which imbine with an equivalent or 114 parts of tartrate of potash, to form b- e equivalent or 220 parts of ferrotartrate of potash. REAGENTS. RESULTS. S’. BUartrate ^l Jq.Tartaric Acid 66 } 1 eq‘ Tartrate ofSesquiox. Iron 106 jl eq. Ferro-tartrate of 'otash 180 i 1 eq. Tartrate Potash 114 . j Potash, 220 i The processes of the Dublin and Edinburgh Colleges are much Inferior to the above, and need not be minutely described. A mixture iron, bitartrate of potash, and water, is exposed to the air, by which £3 iron is converted into sesquioxide, and combines with the bitartrate. Properties.—It is an olive-brown inodorous powder, with a styptic tay taste. It reacts on vegetable colours, mildly alkaline. It is slightly 1 liquescent, probably from the tartrate of potash which it contains. It sssolves in about four times its weight of water, and slightly in alcohol. 'Characteristics. Ferrocyanide of potassium does not occasion any i.ie colour with it, unless a few drops of acid be added. Potash, soda, and • -ir carbonates, do not decompose it at ordinary temperatures, nor does mionia or its carbonate even by the aid of heat. Tincture of nut alls i uses a dark-coloured precipitate. Sulphuric, nitric, or hydrochloric lid, throws down the sesquioxide of iron from a’solution of this salt- excess of acid redissolves it: the solution has then a very astringent •4te. Tartaric acid causes the formation of crystals of tartar. Heated a covered crucible, ferrotartrate of potash yields charcoal, carbonate potash, and protoxide of iron.