Ulcers are referred to as _healthy_ when the process of granulation is proceeding with average rapidity; _indolent_, when the reverse prevails; _sloughing_, when there is actual visible tissue death in connection with the ulcerative process; _phagedenic_, when the gangrenous tendency is well marked and the process exceedingly rapid; _irritable_ or _erethistic_, when the surface is exquisitely sensitive; _hemorrhagic_, when bleeding easily; _fungous_ or _fungoid_, when the granulations have risen above the surface and are increasing at too rapid a rate. There is a peculiar form of ulcer, seen mostly upon the face, to which the name _rodent ulcer_ (also lupus exedens) has been given. This is now known to be a slowly growing form of epithelioma, and is described in Chapter XXV. The best examples of the indolent ulcer are seen in connection with varicose veins of the extremities; of the phagedenic ulcer, in certain cases of chancroid; of the irritable ulcer, in ulceration of the cornea, when the pain and photophobia are intense; or in fissured ulcer of the anus, where the pain and sphincter spasm are sometimes agonizing. Ulcers are described according to their _shape_ as _regular_ or _irregular_; as _fissured_, when they extend more or less deeply and abruptly into the surface involved; as _fistulous_ when they have a tubular arrangement; as _rodent_, when they spare nothing in their course. The _borders_ of ulcers are described as _healthy_, _indurated_, _tumid_, _edematous_, _undermined_, _livid_, _inflamed_, etc., these adjectives explaining themselves. The _surfaces_ of ulcers are described as _healthy_ when they have normal color and appearance, _inflamed_, _excavated_, _covered with sloughs_, _callous_, etc. The _callous_ ulcer is one which exhibits little change from month to month; its surface is dirty, and its secretion thin and mucopurulent. It is usually sunk considerably below the surrounding level, while its border is firm and nodular. The best examples of this form are those accompanying varicose veins. In size or area ulcers may vary from the slightest local destruction of tissue to an area covering an entire limb or a large part of the trunk. In depth they vary within lesser limits; while an external ulcer may connect with some deep lesion by means of a tubular passage or _sinus_. It thus appears that the term ulcer may be applied to the result of a natural effort to repair loss of substance without introducing the element of disease, or that it may be the consequence of local infection with local tissue disaster.