The most common remote cause of spontaneous mortification is a rigid state of the arteries, most frequently met with in the inferior extremities of elderly persons, in consequence of the deposition of calcareous matter between the internal and middle coat; this calcareous degeneration may be confined to a part of the limb, or may pervade the whole of it, and even extend throughout the arterial system. There are many cases in which disease of the arteries has existed, though no gangrene occurred; but this by no means invalidates the assertion, since, when arteries are thus affected, the part cannot withstand sphacelus when exposed to any of its immediate causes. An attempt has been made to connect mortification with an inflamed state of the arterial coats. This opinion is not confirmed by experience. Obstruction from coagulation of their contents, and inflammation of the venous trunks, sometimes precedes death of the extreme parts in old people, and seems to act as a direct cause. After wet seasons, spontaneous gangrene has prevailed as an endemial disease on the Continent, where rye is a principal article of food. The rye is subject to a disease called _Ergot_; the grains become large, black, and have a horny consistence; and the use of it, when thus diseased, is assigned as the cause of gangrene. The patients who have suffered from the use of this ergot or cockspur rye have experienced pain and heat, with swelling, generally in the lower limbs, though occasionally in the upper. These symptoms abating, the parts became cold, insensible, and discoloured, and were gradually separated from the body. The disease attacked patients of both sexes and every age, did not appear to be infectious, and was frequently fatal. It has occurred in this country from the use of unsound wheat. A tendency to mortification sometimes arises from a peculiar state of the atmosphere, want of cleanliness, poor and irregular diet, &c. Cancrum oris, for example, and sloughing of the pudendum in children, occur in those of the poorer classes who live in low, damp, and dirty situations; and little or no incited action precedes the sloughing. The same may be said of the phagedænic affections of the genital organs. Mortification and ulceration seem to differ merely in this,—in the latter, a part which, from any cause, is unfitted to remain a portion of the living body, is only prevented from dying by absorption just as it is about to lose its vitality; whilst in mortification the part perishes too soon, or in too great quantity, to admit of absorption. Sloughing phagedæna is a sort of connecting link.