An Ulcer is a Rupture of the Natural Union of the Parts made a long while ago, which is maintain'd by the Sanies that runs out of its Cavity; or an Ulcer takes its Rise from a Wound that cou'd not be well cur'd in its proper time, by reason of the ill quality of its Pus or corrupt Matter.
What difference is there between a Wound and an Ulcer?
It is this, that a Wound always proceeds from an external Cause, and an Ulcer from an internal, such as Humours that fall upon a Part; or else a Wound in growing inveterate degenerates into an Ulcer.
Whence is the difference of Ulcers deriv'd?
It is taken from the Causes that produce 'em, and the Symptoms or Accidents with which they are accompany'd. Thus upon Account of their Causes they are call'd Benign or Malignant, Great, Little, Dangerous, or Mortal; and by reason of their Accidents, they are term'd Putrid, Corrosive, Cavernous, Fistulous, Cancerous, &c.
Do Ulcers always proceed from external Causes, or from an outward Wound degenerated?
No they sometimes also derive their Origine from internal Causes, as the Acrimony of Humours, or their Malignant Quality; the Retention of a Splint of a Bone, and other things of the like Nature. These Ulcers are commonly call'd Primitive, and the others Degenerate.
What are Putrid, Corrosive, Cavernous, Fistulous and Cancerous Ulcers?
The Putrid Ulcer is that wherein the Flesh is soft and scabby, the Pus and Ichor being viscous, stinking, and of a cadaverous smell.