Inflammatory action is seldom so intense as to terminate in death of the part, unless the power of that part has been diminished by previous local or constitutional disease, or by injury; and the inflammation preceding gangrene is all along attended by symptoms of so well-marked debility, both local and general, that it is frequently designated the Inflammatio Debilis. Of inflammatory affections, the erysipelatous most frequently terminates in gangrene; in other words, the power of resisting incited action is not so great in the cellular tissue and skin as in other parts of the body. [Illustration] The period at which the symptoms of gangrene appear after an accident varies, in general, according to the severity of the injury. As was already observed, the part may be immediately deprived of its vitality—if not, symptoms of gangrene sometimes appear within a few hours after reaction has taken place; while in other cases, tension, pain, and heat occur, and may continue for a longer or shorter time, according to the degree of power remaining in the part. Tension often exists to a great extent after severe injuries, from extravasation of blood or serum; the functions of the vessels are thereby interrupted, and gangrene is inevitable. As the action proceeds, the pain and heat often subside—the parts become flaccid—dark-coloured serum is effused beneath the cuticle, forming what are termed Phlyctenæ—the skin becomes dull and livid—dark streaks extend along the limb, perhaps from the colouring matter of the blood transuding, as in commencing putrefaction in the dead body—air is effused into the subcutaneous cellular tissue, causing a sense of crepitation when pressed by the finger—sloughs form, either black or of an ash colour—and the gangrene involves a greater or less extent of the limb. The mortification is here represented as attacking a limb that had suffered from compound fracture. The dark part around and above the protruded bone was in a state of sphacelus. The dorsum of the foot and the integument towards the knee were only gangrenous. The patient was advanced in life, and the state of the constitution such as to induce a belief that there was a predisposition to mortification. The removal of the limb was, under the circumstances, reckoned inexpedient. In some instances, the mortification is most towards the surface; in others, it is chiefly amongst the deeply seated parts. Sudden cessation of pain is generally regarded as an unequivocal sign of the occurrence of gangrene, especially in the internal viscera; but it not unfrequently happens that the painful sensations suddenly cease, whilst no gangrene supervenes, and that a part mortifies, whilst the pain continues but little abated.