Gangrene as the result of infectious processes is seen in phlegmonous erysipelas, where death of tissue seems to be due to the combined influence of the invading organisms and of mechanical agencies--_i. e._, tension produced by stasis and exudation, with such stretching of tissues or overcrowding with inflammatory products as to virtually strangle them, in consequence of all of which they die. Gangrene of an entire hand may thus result, or, more commonly, the gangrene is limited in extent to the more superficial parts, so that sloughs separate. A specific form of gangrenous inflammation known as _malignant edema_, due to a peculiar anaërobic bacillus, will be treated of separately under a distinct heading. Quite like it in several respects is the gangrenous emphysema of certain writers, known also as the fulminating form, or, as the French call it, the “_gangrène foudroyante_.” More or less emphysematous condition may accompany malignant edema; yet that we do have gaseous forms of gangrene without the specific bacillus of malignant edema is established. At least sixteen cases of so-called gaseous gangrene due to infection by the _bacillus aërogenes capsulatus_ are on record, of which twelve were fatal. Most of them followed surgical injuries--_e. g._, compound fracture. [Illustration: FIG. 16 Noma. (Original.)] _Hospital gangrene_, so called, has been in years past the terror of military surgeons and camp hospitals. As a type it has almost completely disappeared from observation, and, in its old manifestations at least, is now practically never seen.