Origin and Properties

This is prepared by melting together sulphur and carbonate of potassa. The carbonic acid escapes, and the sulphur and potassa mutually react so as to produce sulphuret of potassium and sulphate of potassa, which are, therefore, the ingredients of the preparation. The sulphuret contained in it, and upon which its peculiar medical virtues depend, is supposed to consist of three equivalents of sulphur and one of potassium, and consequently to be a tersulphuret of potassium. in the recent state, it is of a liver-brown colour, which has given rise to its ordinary name. When perfectly dry, it is inodorous; but, if moistened, it acquires a slight smell of sulphuretted hydrogen. its taste is acrid, alkaline, bitter, and very disagreeable. it is dissolved by water, forming an orange-coloured solution, which slowly evolves sulphuretted hydrogen, probably through the action of the carbonic acid of the air.

Almost all acids decompose it, with the formation of sulphuretted hydrogen, and the deposition of the excess of sulphur. By exposure to the air, it absorbs oxygen, the sulphuret is changed successively into the hyposulphite, sulphite, and sulphate of potassa, and the colour becomes green, and ultimately whitish.

Effects on the System

The effects of sulphuret of potassium appear to consist of those of an alkali, combined with those of sulphur or of sulphuretted hydrogen. Locally, it is irritant, and applied, in a concentrated state, to any sensitive surface, whether external or internal, will produce inflammation, and even corrosion. internally, its immediate effects depend, in some degree, upon the contents of the stomach. if there is acid among them, this is neutralized, a mild neutral salt is substituted for the acrid sulphuret, and sulphuretted hydrogen is evolved. if not, the sulphuret operates directly on the stomach, with an irritant influence proportionate to its quantity, and, being gradually absorbed, produces its effects on the constitution. Under these circumstances, it probably enters the circulation in the condition of sulphuret, and there reacts with the oxygen of the blood so as to be partly converted into a sulphate, in which state, as well as in its own state unchanged, it is thrown out by the emunctories. Should an acid have been encountered, and sulphuretted hydrogen have been evolved, this is absorbed; but, at the moment of mixing with the blood, it must react with the soda of that fluid so as to form sulphuret of sodium, which then acts and is eliminated, in like manner as the sulphuret of potassium just referred to. it seems, then, that, whichever of these preparations of sulphur is taken, whether the element itself, sulphuretted hydrogen, or one of the sulphurets, and whether or not the latter encounters an acid in the stomach, though the degree of local irritant effect may differ, the influence on the system at large is the same, at least from proper medicinal doses.

When taken duly, sulphuret of potassium acts as a moderate stimulant, increasing the frequency of the pulse, heat of skin, and the various secretions, particularly, it is thought, the mucous secretion and that of the liver. Some suppose it to operate with a special influence on the pelvic viscera, determining the menstrual and hemorrhoidal flux; but this, when observed, is probably a mere accidental direction of a general influence.

In over-doses, it irritates the primae viae, sometimes producing nausea, vomiting, and purging; and, in large quantities, acts as a violent acrid narcotic poison; death sometimes following in so short a period as fifteen minutes. The symptoms are severe burning pain in the throat and stomach, perhaps vomiting, and speedy and great prostration, attended with convulsions. The best antidote is probably sulphate or acetate of zinc, with free dilution. A joint emetic and antidotal effect might be expected. The state of system remaining must be met, in accordance with the obvious indications.

Therapeutic Application

Carefully administered, sulphuret of potassium may prove useful in the complaints before mentioned as being benefited by the use of sulphur. It has been particularly recommended in chronic affections of the mucous membranes, attended with copious mucopurulent discharges, such as chronic bronchitis, catarrh of the bladder, etc. In common with other alkaline sulphurets, it has been used in pseudomembranous croup, in the hope of modifying the plastic secretion, and thus favouring the expulsion of the membrane; but the results have not been such as to encourage its further employment. Indeed, the medicine is at present almost never prescribed internally; as all its good effects can be obtained by milder remedies, less disposed to irritate the stomach, and less dangerous in over-doses.

The dose is from two to six grains, which may be given dissolved in from four to eight fluidounces of sweetened and aromatized water, and repeated twice daily. It may also be administered in pill, which, however, is a less eligible form.

External Use

It is chiefly as a topical or external remedy, that sulphuret of potassium is now used. It may be applied in the form of ointment, lotion, or bath.

The ointment may be made by rubbing half a drachm of the sulphuret with an ounce of lard. It may be used in cutaneous eruptions, as scabies, psoriasis, pityriasis, and the chronic and dry state of eczema, and of impetigo.

Lotions may be made of various strengths, from one drachm or less to two drachms to the pint of water. These are employed in the cutaneous affections just mentioned, and also for injection into the nostrils, ears, vagina, urethra, and even the rectum, in chronic muco-purulent discharges from these parts.

The bath is a much more important remedy. Artificial sulphurous baths generally consist of a solution of this salt, or of sulphuret of sodium, which so precisely corresponds in effect with the analogous compound of potassium, that what is said of one may be considered as belonging equally to the other. I shall first treat of the effects of these baths, and then of their application. They are usually applied warm, or in various degrees hot; as the effect to be produced is essentially excitant, and consequently is favoured by an elevation of temperature.

Considerable irritation of skin is produced, which reacts on the system, and joins with the heat, and the constitutional influence of the medicine, to cause a general excitement, sometimes amounting to fever. In some persons, this is so readily induced as to render them unfit subjects for the remedy. Not unfrequently the irritation of skin, especially if the solution be strong, the temperature high, and the period of immersion protracted, is attended with a papular or vesicular eruption, which is occasionally extensive and painful. This effect is by some administrators of the remedy considered as essential to its full favourable operation, and is aimed at as the sine qua non in the therapeutics of sulphurous bathing. it is supposed to constitute a sort of crisis, to be an indication of the escape of offensive humours, and must be produced at all events. Perhaps these relics of old times may find advocates in the revived humoralism of the day; but, whatever may be the theoretical views on the subject, care should be taken not to urge their application too far; as some persons obstinately resist this effect of the remedy, and might suffer seriously, if the bath were strengthened, and persevered in without limits, under the impression of its necessity. I presume most therapeutists would agree with me in considering this affection of the surface as a mere result of irritation, and as useful no further than as it might act revulsively against interior diseases, or supersedingly on those of the skin itself.

If the object, in the bathing, be more to bring the system under the sulphurous influence than to irritate the surface, it may be accomplished by the addition of a small quantity of sulphuric or muriatic acid, which will evolve sulphuretted hydrogen, and substitute a mild neutral salt for the acrid and irritating sulphuret. Care, however, must be taken to stop short of the point of saturation, if any effect on the surface is to be produced. When the acid is used, a portion of the sulphur is precipitated, as well as of sulphuretted hydrogen evolved.

These sulphur baths act by producing an excitant effect throughout the ultimate organic structure, substituting anew and self-limited action for that previously existing; perhaps, as in the case of mercury or iodine, changing the very structure itself by stimulating the disintegrating process, and causing a healthier nutritive deposition, in the place of the diseased tissue removed. in other words, they are an alterative remedy. This influence is felt especially in the skin, and it is here, consequently, that their curative effects are most obvious. But, beside this alterative operation, they act revulsively, in relation to internal diseases, by the irritation they produce upon the surface.

The complaints in which they are perhaps most beneficial are all old, obstinate cutaneous eruptions, in which the skin has become organically changed by the disease, with little or no remaining tendency to active irritation or acuteness of inflammation. Lepra, psoriasis, pityriasis, old eczema and impetigo, and obstinate prurigo, are examples of the kind. Scabies, too, almost always yields to this remedy.

Under sulphur, the various general or constitutional diseases have been mentioned in which the baths are most used. Chronic rheumatism, irregular and chronic gout, chronic mucous inflammations, whether of the bronchia, the stomach and bowels, or the urinary and genital passages, consequently chronic catarrh, cystirrhoea, leucorrhoea, diarrhoea, and dysentery, scrofulous affections without fever, and secondary syphilis, constitute a catalogue of maladies, offering abundant opportunities for the beneficial influence of this therapeutic measure. inertness of the liver, and amenorrhoea are often also benefited by the stimulant influence extended to the hepatic and uterine functions respectively.

Another important application of the sulphurous baths is to obviate the poisonous effects of lead on the system. But enough has been said on this subject under lead.

Contraindications are offered, as before stated, by fever, acute inflammation, and tendencies to high vascular irritation; and, whenever the bath is observed to develop these conditions, it should be suspended for a time, or abandoned.

The ordinary strength of the bath is four ounces of the sulphuret to thirty gallons of water; but, to meet special cases, it may be diminished down to two ounces or increased to six. The patient may remain in the bath from half an hour to two or three hours; and the bathing may be repeated daily, or less frequently as the case may require. Care should be taken, when an acid is added, that sulphuretted hydrogen should not be so copiously evolved as to occasion serious inconvenience if inhaled. The bath should be prepared in a wooden tub.