necessary to enlarge freely the external opening, in all cases where the dead portion of bone is of considerable size. If, on thus exposing the parts, the sequestrum be found detached, but still firmly bound down by the substitute bone, deposited over it either in one continuous sheet, or in irregular columns, this must be divided by a trephine, a small saw, or cutting pliers, before the sequestrum can be extracted. When a dead portion of bone, of considerable length, is exposed at its centre, whilst its extremities are entangled by the old or substitute bone, the division of the exposed part of sequestrum, by means of the cutting pliers, will often be sufficient for its removal, the cut ends being seized by the forceps, and one half removed after the other; thus the perforation or removal of any portion of the substitute will be rendered unnecessary. The instruments, and especially those for extraction, ought to be very powerful, and suited to the purpose; for in the employment of inefficient means there is much folly and cruelty. Incisions into a necrosed limb are attended with profuse hemorrhage from the enlarged and excited vessels; and in some cases it is with difficulty arrested, in consequence of retraction of the cut ends of the vessels not taking place within the condensed and indurated parts. Pressure, and an elevated position of the part, will generally be found to answer. When necrosis has been extensive, the limb must be carefully supported by the application of splints and bandage, till the process of reparation be completed, in order to prevent fracture of the recently formed substitute. This proceeding is seldom, however, necessary. The treatment may be summed up in a very few words. Prevent the necrosis, if possible; open abscesses whenever they appear; encourage the patient to move the neighbouring joints; support the strength; remove sequestra when loose, but do not interfere till they are ascertained to be so; give the limb proper support and rest, when a large sequestrum is formed. When fracture has taken place, when the health has been undermined, or when neighbouring joints have become diseased, amputate, in order to save the life, if it be impossible to save the limb. [Illustration] It is almost superfluous to remark, that leeching and blistering are worse than useless after necrosis has occurred, however useful they may be in preventing it; and that the adoption of measures to promote the dissolution and absorption of the sequestra are glaringly absurd. Necrosis, after amputation, was formerly frequent; but in the present improved state of this operation it is so rare as scarcely to demand separate consideration. [Illustration]