Numerous growths of cancerous nature are met with in bone; they are distinguished from one another by their internal structure and external configuration, as well as by the mode in which they destroy the tissue of the bone.

a. The least frequent is areolar cancer. It forms tumors of greater or less dimensions which protrude from the interior of the bone, and sometimes it exhibits in bone, as in other structures, its remarkable character of developing its peripheral follicles into large bladders or cysts.

I have met with a case of this kind in the right superior maxillary bone-In the neighborhood of the canine fossa, a white and densely honeycombed tissue sprang out of the bone, within the small cells of which a grayish jelly was enclosed: internally it filled the cavity of the antrum Highmorianum, while externally it grew in the form of bladders, which attained such a size, that at length those at the periphery of the growth would have contained a hen's or goose's egg, and the whole mass was as large as a man's head.

B. Fibrous cancer appears sometimes in the form of a nodule, of about the size of a walnut or a hen's egg, which is developed mostly in the medullary canal of the long bones: it displaces the bony tissue, and producing atrophy of it by pressure, is frequently the cause of one or more spontaneous fractures of the bone, which occur upon the most trifling occasion. Sometimes it springs from a broader basis on the surface or in the interior of a bone, becomes a tuberculated and uneven, lobulated mass, and often reaches a very large size: it splits the tissue of the bone asunder into filaments and laminae; and new osseous substance, commencing on them at the base of the growth, and developed continuously along the principal fibres in its interior, forms for it a bony skeleton. This kind of cancer is noticed mostly in the bones of the skull and face, and in the long bones.

y. Medullary cancer appears in the following forms:

(1.) In one, which is a rare form, the bone is infiltered with a milk-white sap, - a fluid encephaloid mass. A case which was long since described by Saillant, and which has been copied by Lobstein into his chapter on Osteopsathyrosis, ranks, as I believe, in this class: and I am the rather inclined to think so because my own experience furnishes me with a similar case. Its rarity will excuse me for detailing it here, instead of that which Saillant has already published.

A silk weaver, aged 61, had suffered twenty-five years before death from haemoptysis, and twelve years before from typhus; since then, from repeated attacks of influenza, and as long as he could recollect, from rheumatic pains in his limbs. In the last year of his life he was afflicted with very severe sharp pains in his lower extremities, and transient oedema of the feet. The pains at length extended to the trunk, and affected the thorax more especially. Fever, cough, and dyspnoea came on; diarrhoea supervened, and the patient died in an extreme state of marasmus.