Observations on Necrosis

'E now know, that, in the long bones of the human body, a portion of the bony cylinder may be deprived of the living principle; and that, in fuch cafes, nature gradually feparates the living from the dead part. While this feparation is taking place, a new cylinder is formed by an effufion of bony matter, fo as to inclofe the old bone, as it were, in a cafe ; and the new bone conneding itfelf with the extremities of the old, the limb retains its original lhape, and, after a certain time, when the