Antiseptics, a term applied to those substances which resist or check putrefaction.

Prior to the experiments made by Sir John Pringle, for the purpose of ascertaining in what manner bodies are resolved by putrefaction, and the means of accelerating or retarding that process, there prevailed a general notion, that alkalies and volatile salts were of a putrescent tendency. The result of his investigations, however, have demonstrated that this opinion was erroneous ; and that there are considerable antiseptic virtues in these salts. Indeed, daily experience has evinced, that volatiles, when applied to the organs of smell, or taken in substance, are perfectly harmless ; and yet a strong prejudice has hitherto prevailed against their use j from a supposition that these salts, being the produce of corruption, are apt to accelerate putrefaction. Respecting their internal use, nothing decisive can be maintained, unless the nature of the disease be accurately defined. For admitting they have a tendency to promote putrefaction, yet in the languor and obstruction which usually mark its commencement, volatiles, from their aperient and stimulating qualities, may be the means of arresting its progress ; on the contrary, even though they were antiseptic, yet where the humours are disposed to corrupt from excess of heat or motion, these salts, by supporting the cause may aggravate the malady. Hence the only criterion the point, is to inquire whether they accelerate or retard putrefaction, when externally brought in contact with muscular fibres. To decide this question, repeated experiments have been instituted, by uniting salt and spirit of hartshorn various animal substances, and the constant result was, that, so far from promoting, they uniformly reed the putrefactive process. From these facts we are sufficiently warranted to conclude, that, when internally taken as a medicine, and with a proper application to the case, they are likewise antiseptic.

Numerous trials have also confirmed the antiseptic properties of fixed salts, though they appear to be inferior to some resinous substances, and other vegetables. Thus, myrrh, in a watery menstruum, has been found twelve times more antiseptic than sea-salt. Two grains of camphor was a better preservative of flesh than sixty grains of common salt. An infusion of a few grains of powdered Virginian snake-root, exceeded in antiseptic property twelve times its weight of chamomile flowers; and the Peruvian bark possesses nearly the same extraordinary quality. These balsamic vegetables are the more valuable, as they are usually free from acrimony, and may be taken in much greater quantity than either spirits, acids, resins, or even neutral salts.

To the class of antiseptics we may also add fermented liquors, vinous spirits, and even those plants called ant-acids, which formerly were erroneously supposed to accelerate putrefaction, particularly the scurvy-grass and horse-radish.

Antiseptics are prescribed in all putrid and malignant diseases, though not without due precaution, as to the proper time for their exhibition, and the different stages of the disorder. Thus, for instance, bark is a specific in mortifications, or gangrene, when the vessels are relaxed, and the blood disposed to putrefy: but will be unavailing, when the intestinal canal is obstructed, or if there prevail a preternatural tension and fulness. In cases where astringent remedies cannot be employed with safety, contrayerva, snake-root, camphor, etc. may serve as excellent substitutes.—See Putrefaction.