If, on the other hand, we suppose the original derangement to have taken place in the periosteum, we shall be enabled, more easily, to explain some of the phenomena. We then reason thus: The whole of the body had shrunk considerably, from disease, and, the circulation being deprived of a part of its usual vigour, the periosteum, a part possessed of little vitality, was unable to bear the additional extension, which it underwent, across the unyielding bone of the tooth. The blood ceased to circulate in it, and it died. Ulceration of the adjacent parts followed, as a matter of course; and these parts, especially the periosteum, being possessed of but little sensibility, the sympathies of the other parts of the system were but little interested, until an extensive portion of the mucous membrane of the mouth, or a mass of cellular substance, became affected. We certainly see that, in every case but two, the disease commenced in contact with the teeth. This doctrine will also explain the rapid and deep penetration of the ulcer along the roots of the teeth; and the destruction of the bone. We may recur to the statement, that a portion of the fang of every loose tooth was always found deprived of its periosteum. In the two cases excepted, we have seen it apparently begin in the mucous membrane of the fauces; and indeed the manner in which it generally spreads from the gums to the cheek and lips, seems to me, unquestionably, to indicate a greater liability than common to gangrene in more than one part of the mouth. The soreness and pain of the socket, which forms a part of most tooth-achs, might have been reasonably expected here; but neither was ever complained of, even when the teeth were loosening: and, as no fever existed at this time, the original irritation can hardly be considered as inflammatory; excepting perhaps the cases which exhibited redness, and slight swelling of the gums. _Is this disease scorbutic?_--I never observed ecchymoses, nor in more than a single instance any the minutest red specks upon the cutis, which might be thought to resemble petechiae. The patients never fainted; the gums were never spongy, nor did they bleed more than those of any other child would have bled, under an equal degree of violence. I however requested my friend, Dr. HARRIS, who has had ample opportunities of making himself acquainted with scorbutus, to see some patients with me. He complied, with his usual kindness, and pronounced their disease not at all to resemble the scurvy.