Preparation

This was formerly prepared by dissolving subcarbo-nate of iron (U. S.) in muriatic acid, and, after filtration, adding alcohol to the solution. As the subcarbonate of iron of the U. S. Pharmacopoeia consists mainly of sesquioxide of iron, and this, by reaction with muriatic acid, is converted into sesquichloride, there is obtained by this process a solution of sesquichloride of iron in alcohol, with only so much water as was contained in the muriatic acid used. But there is usually, in the subcarbonate above referred to, a small, though uncertain proportion of carbonate of protoxide of iron, producing with the muriatic acid a corresponding proportion of protochloride, which remains in the solution. But protochloride of iron, exposed to the air, is converted, by the absorption of oxygen, into sesquichloride and sesquioxide, the latter of which, being insoluble, has a tendency to render the preparation turbid. If there be an excess of muriatic acid present, it will dissolve the sesquioxide as fast as formed, and thus preserve the liquor clear; but. as this was not the case in the old U. S. formula, the tincture was apt to become turbid on standing. A precipitate was slowly produced, which formed crusts on the bottle, and in this state was insoluble in an excess of muriatic acid, probably from its peculiar state of aggregation.* Another inconvenience incident to the preparation was that, in consequence of the muriatic acid of the shops falling short of the officinal sp. gr. 1.16, the whole of the subcarbonatc directed was not dissolved, and the resulting tincture was, therefore, too weak. If the strong acid could not be obtained, this defect might be obviated, as suggested by Mr. A. P. Sharp, of Baltimore, by passing a little muriatic acid gas, from some liquid mu-riatie acid heated in a Florence flask, through a bent glass tube, into the mixture of the subcarbonate and acid, until a perfect solution was effected, and then proceeding as directed in the officinal process. (Am. Journ. of Pharm., xxvii. 103).

But most of the disadvantages above mentioned have been obviated in the new process adopted in the present Pharmacopoeia, in which a pint of aqueous solution of the sesquichloride is first made by the successive action of muriatic and nitric acids on iron wire, as in the process for preparing the solid sesquichloride; and three pints of alcohol are then added. But, in order to obtain satisfactory results even with this method, it is necessary in the first place to be provided with materials pure and of due strength, and then faithfully to carry out all the directions. (See U. S. Dispensatory).

Properties

The tincture of chloride of iron is a deep-brown liquid, which, in very thin layers, is yellowish, and, applied to white paper, produces a yellow stain. It has a sour, very astringent, and strongly chalybeate taste, and an odour resembling that of muriatic ether, a little of which is probably generated by reaction between the muriatic acid and alcohol. It should have the sp. gr. 0.990; and a fluidounce of it should yield when diluted, and precipitated with ammonia, an amount of sesquioxide of iron weighing, after being washed, dried, and ignited. 29 grains. It is sensible to the ordinary tests for iron. The following substances produce precipitates with it; namely, the alkalies, alkaline earths and their carbonates, acetate and subacetate of lead, nitrate of silver, astringent vegetable infusions, and mucilage of gum arabic.

Effects on the System

This preparation is locally excitant and astringent, and, in excess, highly irritant. Swallowed in moderate doses, it acts as a tonic and astringent upon the alimentary canal, increasing the appetite, promoting digestion, and causing constipation of the bowels. More largely used, it irritates the stomach, and, in great excess, acts as a poison by inflaming the gastric and intestinal mucous membrane. Christison, in his treatise on poisons, mentions a case in which death appeared to result from swallowing a fluidounce and a half of the tincture. There were symptoms of inflammation in the stomach and bowels during life, and the marks of it after death. Upon the system in genera] it produces the ordinary effects of the chalybeates, and is thought, moreover, by some, to operate as a diuretic, and to exert a peculiar influence on the urinary organs. Though I have used the medicine considerably, 1 have not noticed the latter effects, but I do not wish to be understood as denying them. Attention has recently been called to an extraordinary power of coagulating the blood, possessed by a strong watery solution of the sesquichloride, when injected into the blood-vessels; and the tincture would probably have a similar effect.

* Prof. Procter ascertained, at my request, that this precipitate was not an oxy-chloride of iron, for it was dissolved by sulphuric acid without the evolution of muriatic acid. It was, therefore, probably sesquioxide, rendered, as suggested in the text, insoluble in excess of muriatic acid by its peculiar molecular condition.

Therapeutic Application

The tincture may be used with advantage as a tonic in dyspepsia, and a joint tonic and astringent in diarrhoea of relaxation, and in passive hemorrhage from the stomach and bowels It may also be used with a view to bring the system under the influence of iron, and is with many a favourite remedy for this purpose; but it has the disadvantage of being liable to irritate the stomach, if given somewhat too freely; and is inferior, I think, for this purpose, to the powder and carbonate, and to the milder soluble salts, as the double tartrate, or ammonio-citrate. There are, however, special purposes which it may be better calculated to fulfil than those preparations. Through the chlorine in its composition, it has been considered as having alterative properties, which render it more efficient in scrofula than the chalybeates generally : and it has, therefore, been associated with other chlorides, as those pi barium, calcium, and sodium, in the treatment of that affection, when complicated with anaemia. It is supposed also to be more efficacious than most of the chalybeates, in checking hemorrhage from the uterus and urinary passages. It has, indeed, enjoyed considerable reputation.

In consequence of the special influence ascribed to it over the urinary organs. In anemic cases of dropsy, in which chalybeates are indicated, it might be selected preferably to others, from its supposed possession of diuretic powers. It is also well adapted to those cases of anaemia, in which there is a coexisting indication for nitromuriatic acid, as in the form of cachexia attended with copious formation of oxalate of lime in the urine. I have seen this combination very speedily successful under such circumstances. Some surgeons of eminence have found it peculiarly efficient in spasmodic stricture of the urethra, in which it must be used more freely than for other purposes; ten minims being given every ten minutes until it produces the desired effect or nauseates. It has also been recommended in dysury from weakness of the muscular coats of the bladder, in chronic mucous discharges from the same viscus, and from the pelvis of the kidney, in leucorrhoea, gleets, and the advanced stages of gonorrhoea. A very natural explanation of the efficacy of this tincture in diseases of the urinary passages was that, being eliminated along with the urine, it came in contact with the interior surface of the passages, and produced its effects by an immediate action on the seat of the disease; but Dr. A. H. Hassall, of London, has satisfactorily determined, by repeated experiments, that neither the chloride itself, nor either of its constituents, passes out with the urine; and this explanation, therefore, must be abandoned. (Lancet, Dec. 1864, p. 740.) But the absence of the tincture from the passages is no proof that it may not act directly on the diseased tissue; for, if it circulates with the blood, it comes really more closely into contact with the tissue than if merely passing over the outer surface of it; and, if it has any special relation to these organs, it thus has the opportunity of exercising its full influence on them.

A new application has, within a few years, been made of the tincture by Mr. C. Hamilton Bell, of Edinburgh; to the treatment, namely, of erysipelas. He gives it internally, in doses of from fifteen to twenty-five drops every two hours, continued night and day, throughout the complaint, employing no other treatment, except to operate freely on the bowels in the beginning, and afterwards to keep them regularly open. At the time of his published notice, he had used the remedy for twenty-five years, with invariable success. (Ed. Month. Journ. of Med. Sci., a.d. 1851, p. 498.) Other practitioners have employed the remedy, and reported favourably of its effects. I have myself used it in many cases, which all terminated in health at the usual period; though the same result might possibly have happened under other modes of treatment; for, within my observation, this complaint has almost always ended favourably, unless in individuals previously broken down by intemperance or disease. Still, after so uniformly favourable an experience, running through several years of hospital practice, I cannot but think that there is real efficacy in the remedy.

Dr. H. L. Byrd, of Savannah, Geo., has employed a similar treatment, with great supposed advantage, in scarlet fever, and considers the remedy, from his experience with it in twenty cases, as superior to all others in that complaint. He gave it in doses varying according to the age, from half or three-quarters of a drop for an infant six or seven weeks old, to ten drops for a child eight years old, and at intervals varying from four to eight hours. {Charleston Med. Journ., ix. 165, March, 1854).

The tincture has also been given, with supposed benefit, in pseudomembranous angina, or epidemic diphtheria, in which the blood is believed to be depraved in a manner somewhat analogous to that which characterizes erysipelas.

It has also been recommended as especially efficacious in purpura haemorrhagica.

The dose of the tincture for ordinary purposes is from ten to thirty minims, which may be increased to one or two fluidrachms, two or throe times a day.

Externally the medicine has been employed as a stimulant and astringent application to venereal warts, and cancerous and fungous ulcers; and as a styptic to bleeding surfaces.