bodies were weighed with the greatest care and accuracy before and after they were so exposed to the absorbents, and were found unaltered in any respect. A paper, detailing these experiments, is published in the _Medico-Chir. Transactions_. The separation of the dead part from the living is accomplished with greater or less ease, according to the bone which is affected, the state of the constitution, and the general health; in the bones of the superior extremity, this, as well as every other action, proceeds more rapidly than in those of the inferior. It occurs in consequence of absorption of the living part of the bone, which is in close proximity to the dead. The sequestrum, if large, is not pushed off, as some have supposed, by granulations, deposited on the living margin of the bone. A small portion of the inner shell, when completely detached, may sometimes be observed to be extruded from a cloaca by granulations from the living bone. During its progress, matter forms, makes its way to the surface, and is discharged through minute, and often numerous apertures, which afterwards become fistulous. The soft parts are thickened and indurated, and the integuments are red, and sometimes of a livid colour. Formation of matter upon the bone is occasionally the cause of necrosis, the periosteum being destroyed or separated from its connections by the pressure or insinuation of the pus. I have seen several instances in which it followed neglected erysipelas of the lower extremity.