The object of the author in this paper is to state certain observations and experiments by which he considers it to be clearly established, that the periosteal membrane, covering the bones, has the power of secreting osseous substance and of forming new bony matter.

Duhamel, founding on a false analogy, which he supposed to exist between the periosteum and the bone on the one hand, and the bark and wood of trees on the other, was the first to lay down distinctly the theory that bony matter is formed by the investing membrane of the bones. The experiments and observations of Haller and others on the progress of ossification in young animals were believed, however, to militate against this idea, and tended rather to establish the doctrine, that new bony matter is formed by the pre-existing or old bone. Between these two theories, the opinions of physiologists and surgeons are still pretty equally divided.