Therapeutic Application

So far as concerns the alterative and sialagogue effects, enough has been said on this subject already. I would, however, urge on the young practitioner, the importance of a guarded use of the medicine, and of not allowing himself to be deceived, by the impunity with which it is often carelessly given, into the very erroneous supposition that this apparent harmlessness can always be relied on. He should also carefully guard against those influences, above referred to, which are calculated to give intensity to the action of the medicine.

Administration

Calomel may be given in the form of pill, or that of powder. The pill may be made with gum arabic and sugar; but, if desired to act quickly and vigorously, should be freshly prepared. The powder may be given in syrup or molasses.

The alterative dose is from half a grain to two grains, every night or every other night, to be followed, if there has been no action on the bowels, by a gentle laxative in the morning. When the stomach and bowels are irritable, the dose may be one-sixth or one-eighth of a grain, given every hour or two, so that the same quantity may be taken in the twenty-four hours.

For the general mercurial effect, as indicated by the sore-mouth, from half a grain to a grain three times a day may be given in chronic cases, and increased if necessary. in acute cases, the quantity may vary from four to twenty-four grains in twenty-four hours, according to the urgency of the symptoms; the several doses not exceeding, as a general rule, one or two grains. it is much better thus to give the medicine in small and repeated doses, as they are more likely to act on the system, and less liable to produce gastric or intestinal irritation. Should the stomach and bowels be irritable, it may even be advisable to follow the practice of Dr. Law, of Dublin, and give extremely minute doses, as from the twenty-fourth to the twelfth of a grain repeated at very short intervals. It has been found that a much smaller quantity of the mercurial will produce salivation, thus given, than as ordinarily exhibited.

When calomel is found unexpectedly irritating, it should be carefully tested for corrosive sublimate, the presence of which is probably one of the causes of the occasional harshness which it exhibits. Should water in which calomel has been agitated, yield, after fitration, a white precipitate with solution of ammonia, it would indicate the presence of this impurity.

Topical Use. Calomel has been employed topically for various purposes. It has been snuffed up the nostrils in ozaena; blown into the eyes in chronic ophthalmia, with or without specks in the cornea; employed as a gargle, suspended in mucilage, in ulcers of the throat; introduced into the larynx, by inhalation, in chronic inflammation of that organ; injected into the urethra in gonorrhoea; and, in the state of ointment made with a drachm of calomel to an ounce of lard or simple ointment, used as a dressing for indolent or specific ulcers, and by inunction in chronic cutaneous eruptions. It has also been used for fumigation; and some prefer it for this purpose to any other preparation of mercury. According to Mr. Henry Lee, of London, it acts in this way more satisfactorily, when mixed in vapour with the vapour of water. To effect this object, nothing more is necessary than to put under a cane-bottomed chair, on which the patient may be seated, enveloped together with the chair in a blanket, a cup of hot water, and a thin metallic plate with ten grains of calomel sprinkled upon it, and to heat each of these by means of a spirit-lamp. At the end of fifteen or twenty minutes, the patient may wrap himself in the blanket, and go to bed. (Medico-chirurg. Trans., xxxix. 341.)

Calomel has been used by Dr. Scarenzio, by the way of subcutaneous injection, for the cure of syphilis; and out of eight cases, only one proved refractory to the treatment. In all the others, the cure was prompt, stable, and without serious accident whether simultaneous or consecutive. It is true that, two or three days after the injection of the calomel, inflammation came on, terminating in small abscesses; but these were always confined to the subcutaneous cellular tissue, and were promptly cured on the evacuation of the pus. The question suggests itself why the calomel, so mild in its action on the skin and mucous membranes, should here exhibit properties so irritant; and the very plausible reply may be made that, so long as it continues to be calomel, it is un-irritating; but that, in the course of two or three days, it is converted, vol. ii.-20 through the agency probably of the alkaline salts of the blood, into a soluble substance, capable at once of being absorbed and thus affecting the system, and of acting as a local irritant. As a vehicle for the injection of calomel, Dr. Scarenzio prefers glycerin, using three grains of the mercurial to about 20 of the liquid. (Arch. Gén., Janv. 1866, p. 86.)

Jewell's calomel, Howard's calomel, or the hydro sublimate of mercury, is a preparation made by condensing the vapours, as they proceed from the materials for preparing calomel, in contact with steam, whereby they are thoroughly cleansed from corrosive sublimate, and the resulting preparation is obtained in a state of finer division, and more impalpable, than in the ordinary mode of pulverization. Another mode of attaining the same object of minute division is that proposed by M. Soubeiran, of effecting the condensation in a current of air. The calomel thus prepared is whiter, and considerably lighter than that ordinarily used, and, in consequence of its more complete comminution, is said to be acted on more rapidly by the alkaline chlorides, and consequently to be rather more active when taken into the stomach. The latter quality is a disadvantage; as the superiority of calomel over other mercurials is owing to its union of mildness with efficiency; but, from its impalpable character, the hydrosublimate is more esteemed for introduction into the eye.

There are two officinal preparations of calomel intended for use as alteratives, or with the view of obtaining the mercurial influence, which require a brief notice.

1. The Pills of Mild Chloride of Mercury, or Calomel Pills (Pilulae Hydrargyri Chloridi Mitis, U. S. 1850), consisted of calomel made into the pilular form by means of powdered gum arabic and syrup, and contained each one grain of the mercurial. They were intended simply as a convenient form for administration, and to facilitate prescription.

2. The Compound Calomel Pill (Pilula Calomelanos Composita, Br.), or Compound Pills of Antimony (Pilulae Antimonii Composita, U. S.), consist of calomel, with an equal weight of sulphurated antimony, and a little guaiac and molasses. They are often called Plummets pills, after Dr. Plummer, who first employed them. They are considered as peculiarly applicable to scaly and other eruptive diseases of the skin, and chronic rheumatism, especially when of syphilitic origin, and are said to be useful also in chronic hepatitis, and disorders of the digestive organs connected with deficient action of the liver. if, however, it be true, as stated by Vogel, that they are ultimately converted into sulphuret of mercury and terchloride of antimony, they must in the end owe their virtues to the antimonial alone, as the sulphuret of mercury is nearly or quite inert.