What is the Composition of the Potential Cauteries?
They may be made with quick Lime, Soap, and Chimney-Soot; or else take an Ounce of Sal Ammoniack, two Ounces of burnt Roman Vitriol, three Ounces of quick Lime, and as many of calcin'd Tartar; mingle the whole Mass together in a Lixivium of Bean-Cod Ashes, and cause it to evaporate gently to a Consistence: Let this Paste be kept for use in a dry place, and in a well-stopt Vessel. Or else the Silver-Cautery, or Lapis Infernalis may be prepar'd after the following manner:
Take what quantity you please of Silver, let it be dissolv'd with thrice as much Spirit of Nitre in a Vial, and set the Vial upon the Sand-Fire, to the end that two third parts of its Moisture may evaporate: Then pour the rest scalding-hot into a good Crucible, plac'd over a gentle Fire, and the Ebullition being made, the heat of the Fire must be augmented, till the Matter sink to the bottom, which will become as it were an Oil: Afterward pour it into a somewhat thick and hot Mould, and it will coagulate, so as to be fit for Use, if it be kept in a well-stopt Vial. This Cautery is the best; and an Ounce of Silver will yield one Ounce and five Drams of Lapis Infernalis.
What is a Seton?
It is a String of Silk, Thread, or Cotton, threaded thro' a kind of Pack-Needle, with which the Skin of a Part is to be pierc'd thro', to make an Ulcer therein, that hath almost the same effect as a Cautery.
What is most remarkable in the Application of a Seton?
It ought to be observ'd, that the String must be dipt in Oil of Roses, and that one end of it must always be kept longer than the other, to facilitate the running of the Humours.
In what Parts is the Seton to be apply'd?
The Nape of the Neck is the usual place of its Application, altho' it may be made in any part of the Body where it is necessary. It sometimes happens that a Surgeon is oblig'd to use a kind of Seton in such Wounds made with a Sword, or by Gun-shot, as pass quite