The ulcerative processes are, for the most part, results of inflammations already described; and they are especially liable to occur when those inflammations, having been raised to unusual intensity by some unfavorable external influences, either continue intense or repeatedly become so; or when they are called forth by some internal constitutional cause (dyscrasia); or when running their course under such constitutional influence, they give rise to a special product by which the tissues are in a peculiar manner consumed (dissolved). As the inflammations, especially the various exanthematous forms of inflammations present numerous characters, which more or less distinctly manifest the nature of the constitutional affection, so also, and still more, are these characters usually stamped upon the ulcer.

Again, many ulcerations of the skin are produced by the metamorphosis of known adventitious growths in the skin itself or in the tissues beneath it; others are secondary stages of various changes in the texture of the cutis, with which we are not as yet acquainted.

Of this kind the following are examples, although most of them still require minuter anatomico-physical investigation: All ulcers connected with disorder of normal, or what have become normal excretions: all those which originate in a congenital or hereditary, or in an acquired dyscrasia, whether the latter be simple, or combined and modified: all menstrual, hemorrhoidal, and urinary ulcers, as they are called, are therefore of this kind; so also are the abdominal, the gouty, and the scorbutic ulcers, those which exist in psoriasis, the syphilitic and syphiloid, the leprous, scrofulous (tubercular) and cancerous, and the numerous cancroid ulcers. They present many more or less characteristic differences in site and in form, i. e. in the state of their margins and bases, in their disposition to extend superficially or deeply, and in the amount, and especially in the quality of their product: hence the known divisions of ulcers into round, oval, and sinuous; into callous and fungous; into moist and dry, etc.

As the ulcer presents various characteristic peculiarities, so also does the cicatrix.

It is important and interesting to observe the relation subsisting between inflamed and ulcerating integuments and certain subcutaneous structures, especially periosteum and bone: it is seen, for instance, on the cranium and shins, and prevails chiefly in the inflammation and ulcer arising from constitutional causes.

1 [ Gangrenous stomatitis? - Ed].