Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 3

_Prop., &c._ The properties and uses of iron are too well known to require description. Its applications are almost universal. It is remarkably ductile, and possesses great tenacity, but is less malleable than many of the other metals. Its sp. gr. is 7844. It is the hardest of all the malleable and ductile metals, and when combined with carbon (steel) admits of being tempered to almost any degree of hardness or elasticity. In dry air it does not oxidise at common temperatures; but at a red heat it soon becomes covered with a scaly coating of black oxide, and at an intense white heat burns brilliantly with the production of the same substance.

Pure water, free from air or carbonic acid, does not tarnish the surface of polished iron, but the combined action of air and moisture, especially when a little acid vapour is present, causes its surface to be soon covered with rust, which is hydrated sesquioxide of iron (ferric hydrate).

Nearly all acids attack iron; dilute sulphuric and hydrochloric acid do so with considerable energy and the evolution of hydrogen gas. At a red heat iron decomposes water rapidly, hydrogen being evolved, and the black oxide of iron formed. Iron is magnetic up to a dull-red heat, at which point it loses all traces of that property. It melts at about 3300 Fahr. With oxygen, chlorine, iodine, the acids, &c., it forms numerous important compounds. As a remedial agent, when properly exhibited, iron acts as a genial stimulant and tonic, and generally proves beneficial in cases of chronic debility, unaccompanied with organic congestion or inflammation.

The carbonate (ferrous carbonate), as it exists in mineral waters, held in solution by carbonic acid in excess, appears to be the form most congenial to the human body; and from its state of dilution is rapidly absorbed by the lacteals, and speedily imparts a ruddy hue to the wan countenance.

Iron is undoubtedly one of the most valuable articles of the materia medica, and appears from the antiquity of its introduction into medicine, and the number of its preparations, to have been deservedly appreciated.

_Tests._ Iron forms two cla.s.ses of salts, namely, ferrous or proto salts, in which iron exhibits a power of combining with two atoms of any monad element, and the ferric or persalts in which iron has a capacity of uniting with three atoms of any monad element.

The ferrous or proto salts have generally a greenish colour, but yield nearly colourless solutions, except when concentrated. Their solutions are known by the following reactions:--They are not precipitated by hydrosulphuric acid when acid, and but incompletely when neutral. Sulphide of ammonium produces a black precipitate, becoming brown on exposure to the air, insoluble in alkalies, but easily soluble in the mineral acids.

Ammonia and pota.s.sa give a greenish-white precipitate, gradually becoming green and then brown in the air. This precipitate occasionally is of a bluish-black if excess of pota.s.sa is used. The presence of ammoniacal salts interferes with the action of these tests. Ferrocyanide of pota.s.sium gives a nearly white precipitate, becoming gradually blue in the air, and immediately so on the addition of a little weak nitric acid or chlorine water. Ferricyanide of pota.s.sium produces a rich deep-blue precipitate, insoluble in hydrochloric acid. In highly dilute solutions the effect is only a deep bluish-green coloration. Phosphate of sodium produces a white precipitate, which after a time becomes green.

The ferric salts, which are also called the sesqui or persalts of iron, have for the most part a reddish-yellow colour, yielding deep-coloured solutions, which exhibit the following reactions:--They redden litmus paper. Hydrosulphuric acid in acid solutions reduces ferric to ferrous salts, giving a white or yellow precipitate of sulphur only. In alkaline solutions it yields a blackish precipitate, consisting of sulphur and ferrous sulphide. Sulphide of ammonium gives similar reaction. Ammonia and pota.s.sa produce bulky reddish-brown precipitates insoluble in excess.

Ferrocyanide of pota.s.sium gives a rich blue precipitate, insoluble in hydrochloric acid, and readily decomposed by pota.s.sa. Ferricyanide of pota.s.sium deepens the colour, but does not give a blue precipitate, as it does with ferrous salts (proto salts). Sulphocyanide of pota.s.sium gives an intense ruby-red colour to neutral or acid solutions. Tincture and infusion of galls strike a black colour. Phosphate of sodium gives a white precipitate, which becomes brown, and finally dissolves on the addition of ammonia.

_Estim._ The iron may be thrown down in the state of ferric hydrate or hydrated sesquioxide, washed, dried, ignited, and weighed. The weight, in grains, multiplied by 7, indicates the weight of metallic iron.

Fifty gr. of the ore are reduced to powder, dissolved in aqua regia, with the aid of heat, and the solution filtered in order to separate the silica and a little alumina which sometimes is left in an insoluble state; an excess of ammonia is then added to the filtered liquor, which produces a reddish-brown precipitate of ferric hydrate mixed with alumina which is collected on a filter, washed, and boiled with a solution of pota.s.sa, in order to dissolve the alumina; the whole is next thrown upon a filter, washed, dried, carefully ignited, and weighed. The above is well adapted to determine the quant.i.ty of iron in clay ironstone, the most common ferruginous ore in England.

The sulphur in cast and wrought iron, and steel, may be estimated by the following process, invented by M. Koppmayer:--10 grammes of iron, finely produced and sifted, are introduced into a bottle holding from 1/2 to 1/3rd litre. The stopper has three holes. Through one of these pa.s.ses a funnel with a ground-gla.s.s tap, its neck reaching to the bottom of the bottle. Through the second pa.s.ses the tube at right angles, fitted with a tap and reaching also to the bottom of the bottle.

Through the third hole pa.s.ses a delivery tube, connecting the bottle to the condensing apparatus.

This latter consists of a series of bulbs arranged like a staircase, so as to permit the gas to come into the greatest possible contact with the standard solution of iodine in iodide of pota.s.sium, with which the condenser is filled, this solution ought not to be exposed to light.

When the apparatus is arranged as above, the atmospheric air is first driven out of the bottle by means of a current of hydrogen gas, introduced by the tube bent at right angles. When it is considered that the air is entirely expelled, the tap of this tube is closed. The funnel is now filled with hydrochloric acid, its tap is opened, and by means of the application of heat the acid is allowed to run down upon the iron without allowing any common air to enter. Hydrogen and sulphuretted hydrogen are formed which pa.s.s into the condenser.

Acid is thus added until all disengagement of gas ceases. The bottle is then heated till its contents boil, a little water having been first added by means of the funnel. After these operations, hydrogen is allowed to enter anew to sweep out all remaining gases. The iodised solution is then poured out, care being taken to rinse the bulb-tube thoroughly, and t.i.trated with hyposulphite of soda, so as to find the remaining proportion of free iodine. The difference between the original amount of free iodine present in the solution, and the amount thus found, shows the proportion of iodine which has been converted into hydriodic acid, and which is proportional to the sulphur contained in the sample under examination.

=Iron, Preparations of=:--

=Ferric Acetate.= Fe_{2}(C_{2}H_{3}O_{2})_{6}. _Syn._ PERACETATE OF IRON; FERRI SESQUIACETAS, L. _Prep._ Ferric carbonate, 1 part; acetic acid, 6 parts; digest three days and filter. A dark brownish-red, uncrystallisable liquid, very soluble and powerfully astringent. The calcined sesquioxide of iron of the shops, commonly sold as carbonate of iron, does not answer well for this or any of the sesqui-compounds, owing to its being with difficulty dissolved by acids, especially by the weaker ones.--_Dose._ (Of the last) 10 to 25 drops, in water or wine.

=Ferric Alb.u.minate.= _Syn._ FERRI ALb.u.mINAS, L. _Prep._

Precipitate a filtered solution of white of egg with another of ferric sulphate or persulphate of iron, wash the deposit in water, and dissolve it in alcohol holding pota.s.sium hydrate in solution.

This preparation is highly spoken of by M. La.s.saigne as especially adapted by its nature, on theoretical grounds, for combining with the tissues of the body.

=Ferric Citrate.= Fe_{2}(C_{6}H_{5}O_{7})_{2}. _Syn._ PERCITRATE OF IRON, CITRATE OF SESQUIOXIDE OF I., CITRATE OF I.; FERRI CITRAS.

_Prep._ By saturating a solution of citric acid in an equal weight of water with freshly precipitated moist hydrated ferric hydrate, evaporating at 150 Fahr. to the consistence of a syrup, and spreading on gla.s.s plates to dry.

By either of the methods adopted for the AMMONIO-CITRATE, merely omitting the addition of the ammonia. It much resembles the ammonio-citrate, but is only slightly soluble in water, and has a rather less agreeable taste.--_Dose_, 3 to 5 gr.

=Ferric and Ammonium Citrate.= _Syn._ AMMONIO-CITRATE OF IRON: AMMONIO FERRIC CITRATE; FERRI AMMONIO CITRAS. L. There are several preparations in which the term 'citrate of iron' has been applied. That commonly known under this name is really a double citrate of iron and ammonia, and appears to be correctly called 'ammonio-citrate of iron.'

B. P. Liquor Ferric Persulphatis (B. P.), 8; liquor ammonia, 19-1/2; citric acid (in crystals) 4; distilled water, a sufficiency, mix 14 of the solution of ammonia, with 40 of water, and all gradually; the solution of ferric sulphate stir constantly and briskly; let the mixture stand two hours, and put into a calico filter and allow to drain. Wash well the precipitate until it no longer gives a precipitate with barium chloride.

Dissolve the citric acid in 8 oz. of the water, and having applied the heat of a water bath add the precipitate of ferric hydrate previously well drained, stir them together until the whole or nearly the whole of the hydrate has dissolved. Let the solution cool, then add 5-1/2 of the ammonia, filter through flannel, evaporate to the consistency of syrup, and dry it in thin layers on flat porcelain or gla.s.s plates at a temperature not exceeding 100.

_Prep._ (Ph. L.) Ferrous sulphate, 12 oz.; carbonate of sodium, 12-1/2 oz.; dissolve each separately in boiling distilled water, 6 pints; mix the solutions whilst still hot, and allow the precipitate to subside; after a time decant the supernatant liquor, wash the precipitate frequently with water (drain it), add of citric acid (in powder), 6 oz., and dissolve by the aid of a gentle heat; when the whole has cooled, add of liquor of ammonia, Ph. L., 9 fl. oz., and gently evaporate to the consistence of a syrup; in this state spread it very thinly on flat earthenware dishes (or sheets of gla.s.s), dry by a gentle heat, and when dry keep it in well-stoppered bottles.

(Ph. D.) Citric acid, 4 oz.; distilled water, 16 fl. oz.; hydrated ferric oxide, obtained from the sulphate, 5 oz.; liquor of ammonia, 4 fl. oz., or q. s.

(Wholesale.) A mixture of iron filings and citric acid, in powder, with barely sufficient water to cover it, is kept in a warm situation for some days, occasionally stirring the ma.s.s, and replacing the water as it evaporates. A saturated solution is next made in distilled water, there being previously added more citric acid (about half the weight of the acid first used), as required; it is then neutralised with liquor of ammonia (about 1-1/4 oz. of liquor of ammonia, sp. gr. 882, to every gallon of the solution of sp. gr. 1025), and the solution is concentrated by evaporation; the process is then completed as in No. 1. The first part of this process produces a salt of the protoxide of iron, or ferrous citrate, which is afterwards converted, by exposure to the atmosphere, into a citrate of the magnetic acid, or ferri, ferro-citrate, and, lastly, into citrate of peroxide of iron, or ferric citrate.

B. P. Liquor Ferri Persulphatis 8. Liquor ammoniae 19-1/2. Citric acid (in crystals) 4. Distilled water, a sufficiency. Mix 14 of the solution of ammonia with 40 of water, and add gradually the solution of ferric sulphate. Stir constantly, let the mixture stand 2 hours and filter through calico, and allow to drain. Wash until the washing ceases to precipitate barium chloride, dissolve the citric acid in 8 of water, add the precipitated ferric hydrate, and heat in a water bath until dissolved.

Let the solution cool, add 5-1/2 of the ammonia, filter through flannel, evaporate to the consistency of syrup, and dry on flat porcelain plates in thin layers at a temperature below 100 F.

_Obs._ Pharmaceutical writers have been so diffuse in their disquisitions on the preparation of this salt, as would lead to the inference that there is some difficulty attending it. The contrary is, however, the case. The only care necessary is to spread the syrup solution very thinly on warm sheets of gla.s.s to dry, which it will rapidly do if they are placed in an atmosphere of warm dry air, for which purpose a 'drying closet' is the most convenient. The dry salt may then be easily detached from the gla.s.s, and will form thin scales, or lamellae, of great brilliancy and beauty. It is also better to use a little more oxide than the acid will dissolve, as the remainder will be employed in a future operation. Less water may be used, or even a larger quant.i.ty than that mentioned; but in the first case the liquid will become difficult to filter--in the latter it will require more evaporation. Boiling water dissolves about twice its weight of citric acid, and there remains 13/20ths of this quant.i.ty in solution when cold, and it takes rather more than twice the weight of the citric acid in moist hydrated protoxide of iron to produce saturation.

_Prop., &c._ This beautiful salt is of a rich ruby colour, and forms glistening transparent scales, very soluble in aqueous menstrua, and the resulting solution is less easily decomposed by reagents than the solutions of most of the other salts of iron. It is 'compatible' with the alkaline of carbonates and bicarbonates, and several other salts, and is nearly tasteless, advantages which have been perhaps overrated by both prescriber and patient. It is doubtful whether this article has not obtained a larger sale from its pleasing appearance than from its medicinal virtues. Several persons who have prepared it in lumps or powder, by the simple evaporation of the solution to dryness, have been unable to sell it under that form, even at a lower price.

Ammonio-citrate of iron is soluble in water; the solution neither changes the colour of litmus nor turmeric; nor is it turned blue by ferrocyanide of pota.s.sium; but either pota.s.sium hydrate or lime water being added, it throws down ferric hydrate, and ammonia is evolved. From 100 gr. dissolved in water, pota.s.sium hydrate precipitates about 34 gr. of ferric hydrate.--_Dose_, 3 to 10 gr., in water, wine, or bitter infusions.

=Ferric and Strychnine Citrate.= (U. S.) _Syn._ FERRI ET STRYCHNIae CITRAS.

_Prep._ Citrate of iron and ammonia, 500 gr.; strychnia, 5 gr.; citric acid, 5 gr.; distilled water, 9 fl. dr. Dissolve the citrate of iron and ammonia in 1 oz. of the water, and the strychnia and nitric acid in 1 dr.

of distilled water. Mix the two solutions, evaporate the mixture over a water bath, at 140 Fahr., to the thickness of a syrup, and spread on gla.s.s plates, so that the salt, when dry, may be obtained in scales.

=Ferric and Magnesium Citrate.= _Syn._ CITRIC OF IRON AND MAGNESIA; FERRI MAGNESIO CITRAS; FERRI ET MAGNESIae CITRAS, L. _Prep._ As the last, but using carbonate of magnesium instead of ammonia to neutralise the solution.--_Dose_, 2 to 10 gr. It has been recommended as a chalybeate in the dyspepsia of gouty and debilitated habits.

=Ferric and Quinine Citrate.= _Syn._ CITRATE OF QUININE AND IRON; FERRI-QUINIO-CITRAS, L. As the ammonio-citrate, but using quinine, recently precipitated, instead of ammonia, to neutralise the acid.

B. P. Pure ferric hydrate is prepared from liquor ferri persulphatis, 4-1/2 pints, and liquor ammoniae, 8 pints, as in the ferric and ammonium citrate. Sulphate of quinine 1 is mixed with water 8, and sulphuric acid 1-1/2, and when dissolved, ammonia added until the quinine is precipitated. The precipitate is collected and washed with 30 of water.

Citric acid 3 is dissolved in 8 of water by the aid of a water bath, and the ferric hydrate, well drained, added; stir together until dissolved, and add the quinine, stirring well until all is dissolved, and allow to cool; add 1-1/2 of solution of ammonia diluted with 2 of water, stirring the solution briskly until the quinine at first thrown down by the ammonia is redissolved; filter and evaporate to a syrup, drying in thin layers on flat porcelain or gla.s.s plates at a temperature of 100.

Ferric citrate, 4 parts; citrate of quinine, 1 part; distilled water, q. s.; dissolve, gently evaporate, and proceed as directed for ammonio-citrate of iron. Greenish golden-yellow scales when prepared by the B. P. process, soluble in 2 parts of water, and somewhat deliquescent; entirely soluble in ether; taste bitter as well as chalybeate.--_Dose_, 2 to 6 dr.; in cases where the use of both iron and quinine is indicated.

=Ferric and Sodium Citrate.= _Syn._ FERRI SODIO-CITRAS, FERRI ET SODae CITRAS, L. _Prep._ From citric acid, carbonate of sodium, and iron or the hydrate, as the ammonio-citrate or pota.s.sio-citrate.

=Ferric Chlo'ride.= Fe_{2}Cl_{6}. _Syn._ SESQUICHLORIDE OF IRON, PERCHLORIDE OF IRON, PERMURIATE OF I.; FERRI SESQUICHLORIDUM, L. _Prep._ 1. (Anhydrous.) By pa.s.sing dry chlorine over heated iron filings. Brown scales.

(Hydrated.) Dissolve ferric hydrate in hydrochloric acid, evaporate to the consistence of a syrup, and crystallise. Yellow or red scaly crystals. The impure solution of this salt has been greatly used as a sewage deodoriser.

See TINCTURE.

=Ferric and Ammonium Chloride= (Fe_{2}Cl_{6}NH_{4}Cl.Aq). _Syn._ DOUBLE CHLORIDES OF IRON AND AMMONIUM, AMMONIO-CHLORIDE OF IRON; FERRI AMMONIUM CHLORIDUM.

Ferric oxide, 3 oz.; hydrochloric acid, 1/2 pint; digest in a sand bath until dissolved, then add of ammonium 2-1/2 lbs., dissolved in water, 3 pints; filter the liquid, evaporate to dryness, and reduce the ma.s.s to coa.r.s.e powder. Orange-coloured crystalline grains readily soluble in water.

Ammonio-chloride of iron is tonic, emmenagogue, and aperient.--_Dose_, 5 to 15 gr.; in glandular swellings, obstructions, &c.

=Ferric Ferrocy'anide.= (Fe_{4}(FeCy_{6})_{3}. 18Aq). _Syn._ SESQUIFERROCYANIDE OF IRON, PRUSSIAN BLUE; FERRI FERROCYANIDUM, F.

SESQUIFERROCYANIDUM, L. _Prep._ Ferrous sulphate, 4 oz.; water, 1 pint; dissolve, add to the solution of nitric acid, 6 fl. dr., in small portions at a time, boiling for a few moments after each addition; next dissolve ferrocyanide of pota.s.sium, 4-1/2 oz., in water, 1 pint, and add this last solution, by degrees, to the first liquid, stirring well each time; lastly, collect the precipitate, wash it with boiling water, drain, and dry it.--_Dose_, 3 to 5 gr., three or four times daily, as an alterative, febrifuge, and tonic, gradually increasing the quant.i.ty until some obvious effect is produced; in agues, epilepsy, and neuralgia. See PRUSSIAN BLUE.

=Ferric Hydrate.= Fe_{2}(HO)_{6}. See under Ferric Oxide.

=Ferric Iodide.= Fe_{2}I_{6}. _Syn._ FERRI PERIODIDUM, L. _Prep._ Freely expose a solution of ferrous iodide to the air; or digest iodine, in excess, on iron, under water, gently evaporate, and sublime. A deliquescent, volatile red compound, soluble in water and alcohol. It is rarely employed in medicine.

=Ferric Oxide.= Fe_{2}O_{3}. _Syn._ SESQUIOXIDE OF IRON, PEROXIDE OF IRON, RED OXIDE OF I.; FERRI SESQUIOXYDUM, F. PEROXYDUM, F. OXYDUM RUBRUM, L.

This substance is found native under several forms, but that employed in the arts is prepared by one or other of the following methods:--