_Mortification_, or the death of a part, is also one of the results of inflammatory action, and the term has been subdivided into _Gangrene_ and _Sphacelus_. Gangrene is that state in which the larger arterial and nervous trunks still continue to perform their functions; a portion of the natural temperature remains, and the part may be supposed still capable of recovery. Sphacelus, again, expresses complete death, when, putrefaction being no longer resisted, the part becomes black, cold, insensible, and fetid; but, in general, the distinction between the terms is not strictly attended to. A division of more importance is into humid and dry, or traumatic and chronic, gangrene; humid or traumatic being applied to mortification produced by external injury; dry or chronic to that resulting from a constitutional cause. Mortification is not always a result of inflammation; it is sometimes preceded by incited action of the vessels, sometimes not. It follows as a matter of course that if inflammatory action is so violent as to cause stagnation of blood in most or all the vessels of a part, and this is continued, there must be a consequent failure of nutrition, which will terminate in mortification. Humid or traumatic gangrene frequently occurs without previous inflammation, the injury being so severe as at once to deprive the part of its vitality. Dry or chronic mortification is often unpreceded by inflammatory action, or at least it is slight and of very short duration. It is preceded by stagnation, or is at all events coincident with this stagnation, not in the smaller vessels only, but in the trunks leading to the affected part. In humid gangrene, swelling with erethismus generally precedes the death of the parts; whereas in the dry, whether the surface change colour immediately or not, they shrink immediately. In the former they quickly lose their vitality, and consequently retain a considerable portion of their fluids; in the latter the process is much slower, and they become dry and shrivelled.