This is a class of medicines formed without any precise or definite object. Obstruction was a cause of convenient application, from its vague indefinite meaning; and, while Ientor and viscidity were the sources of diseases, deobstruents were common remedies. We declined speaking of them in the class of aperients; as for these medicines there was an apparent foundation, we mean not to say that there is not some foundation for the present group . it is less clear and satisfactory-obstruction, during the reign of the humoral pathology, was, as we have hinted, frequently introduced as a cause; but though fevers and inflammations were then ultimately resolved into obstruction, deobstruents were confined exclusively to chronic complaints: of these, infarctions of the viscera were chiefly attacked by gentle laxatives, from this effect styled aperients, of which we have already spoken.

The obstructions to be removed by this class of [ dicines, are those of natural discharges, or infarctions of organs, whose utility is less obvious, and from which no excretory ducts proceed. The natural discharges, to restore which we employ deobstruents, are those of the menses, of the haemorrhoidal vessels, of the nose, the lungs, and the skin. The first we must treat of under the title of Emmenagogues; the second we have spoken of in the article Cathartics; the others will occur under the articles of Errhines, Expectorants, and Diaphoretics. Our present object is, then, those tumours out of the circulation, or in parts where the circulation is languid, and from which no excretory ducts proceed.

We have already stated, that where obstruction occurs, two modes of treatment offer themselves to our notice; the one consists in forcing on the circulation, by increasing the vis a tergo; the other in moderating too great action, 'in order to prevent the fluids from being further impacted, the obstruction increased, and suppuration supervening. The first can seldom be effected by violent stimulating remedies; yet we have had occasion to show, that mercury, by slowly and steadily increasing the action of the arterial system, and of course the momentum of the blood, sometimes succeeds. It certainly, at times, removes complaints of the liver; sometimes, though rarely, scirrhous tumours of the breast, and other parts where its topical application by friction can be combined with its internal stimulus. The internal use of arsenic, in cancers, must be referred to the same head; and other stimuli sometimes succeed in different complaints. The tartar emetic ointment has been useful in bronchocele, and occasionally in the white swelling of the knee. In the latter also, the arum, and the gum ammoniacum, with squills, have been successful. These, then, are deobstruents from their stimulus. When the application of sea weeds and sea salt, with their internal use, relieves cases of scrofula; and mesenteric tabes, or the burnt sponge, under the tongue, lessens the bronchocele; they appear to be useful in the same way.

The sedative or refrigerant deobstruents are medicines of the same classes, though they have not been usually arranged under this head. When we give nitre, and employ the antiphlogistic regimen in cases of tubercles in the lungs, we use them as deobstruents. A similar treatment is often, for the same purpose, adopted in incipient cancers. The general remedies of this class, however, besides opium, are, the cicuta, the lactuca virosa, the belladonna, the aconite, and the various genera of the same order. These have been used as deobstruents in other parts of Europe, it is said, with success. We have to regret that we cannot add our testimony to their efficacy.

It has not been uncommon to unite the two orders of deobstruents; and not long since fashionable to join the extract of cicuta with mercury in tubercular consumptions; arum, with the same preparation, as an application to white swellings; mercury, antimony, and opium, in internal obstructions; and mercury, with camphor, externally applied.

We have enlarged on this class more fully than, perhaps, its importance might have demanded; for, from being highly valued, it has been neglected in the later systems. It was proper, therefore, to show, that the establishmentof this association was not wholly theore-tical, and to point out its real foundation.