It is a kind of gummy and wavering Tumour, which is form'd by the settling of a gross Humour between the Bone and the _Periosteum_. _Are _Exostoses_ and _Nodus_'s suppurable Tumours?_ Yes, because they sometimes produce Ulcers and Gangrenes in the Bone, which are call'd {199} _Caries_, proceeding from an internal Cause; nevertheless they are generally dissolv'd by Frictions with _Unguentum Griseum_, or by the application of Plaisters of Tobacco, or _Emplastrum de Vigo quadruplicato Mercurio_; taking also to the same purpose internal Diaphoretick and Sudorifick Medicines, with convenient Purgatives. * * * * * CHAP. V. _Of Cauteries, Vesicatories, Setons, Cupping-Glasses, and Leeches._ _What is a Vesicatory?_ The Name of Vesicatory may be attributed to every thing that is capable of raising Bladders or Blisters in the Skin; nevertheless in Surgery, by a Vesicatory is understood a Medicament prepar'd with _Cantharides_ or _Spanish_ Flies dried, which are beaten to Powder, and mingled with Turpentine, Plaisters, Leaven, and other Ingredients. _In what places, and after what manner are Vesicatories usually apply'd?_ They are apply'd every where, accordingly as there is occasion to draw out or discharge some Humour from a Part: In Defluxions of Rheum upon the Eyes or Teeth, they are laid on the Neck and Temples; in Apoplexies, behind the Ears; and so of the rest, observing always to make Frictions on the places where the {200} Application is to be made, to the end that the Vesicatory may sooner take effect. _How long time must the Vesicatory continue on the Part?_ The Blisters are generally rais'd by 'em within the space of five or six Hours; yet this Operation depends more or less upon the fineness of the Skin; and when the Bladders or Blisters appear, it is requisite to deferr the openning of 'em for some time, to the end that Nature may have an Opportunity to introduce a new Scarf-Skin, by which means the Pain may be avoided that would be felt, if the Skin were too much expos'd to the Air. _What is a Cautery?_ It is a Composition made of many Ingredients, which corrode, burn, and make an Escar on the Part to which they are apply'd. _How many sorts of Cauteries are there in general?_ There are two kinds, _viz._ the Actual and the Potential; the former are those that have an immediate Operation; as Fire, or a red-hot Iron; and the others are those that produce the same Effect, but in a longer space of time; such are the ordinary Cauteries compos'd of Caustick Medicaments. _Which are the most safe, the Actual or the Potential Cauteries?_