These formations are, on the whole, a rare appearance in the bony system; by far the most frequent of them is cancer. Those which originate in some general diseased condition, are usually the expression of a high degree of it, especially when such diseased condition has the character of dyscrasia: it is, however, a fact of great importance, though it has not yet received much notice, that the dyscrasia, which has established itself in a bone, usually remains fixed there for a long time, and spreads, for the most part, only upon some evident cause, such as forcibly effacing its localized character, that is extirpating the local affection. With regard to that disease, which old writers named spina ventosa, and which has, since their time, been represented in such different forms, I think it best to remark at once, that expansion of bone, from the eventual production of which spina ventosa obtained its character as a disease, is a condition common to several of the morbid growths about to be described.

To the actual new formation in bone, I prefix an account of the morbid development of its system of capillary vessels.

A. Teleangiectasis

It consists in an enlargement of the system of arterial and venous capillary vessels within the bone. It forms rounded soft tumors, which sometimes pulsate, and which attain various, and occasionally very considerable, size. The dilated vessels produce enlargement of the Haversian canals and cells, expansion of the bone, and subsequently by their pressure, absorption of its substance. Generally, also, the vessels become ruptured and hemorrhages ensue; the extrava-sated blood forms roomy cavities for itself in the cellular tissue that connects the convoluted vessels, and there coagulates in layers, just as in the sac of an aneurism (Breschet). From special examination of the disease itself, as well as from having met with cancer in other parts of the skeletons in which it occurred, I have been led to believe that it originates in cancer of the bone. In the skull, moreover, I have observed a cavernous structure developed from the diploe.

B. Cysts

My own experience agrees with published observations of these growths, as to the rarity of their occurrence in bone.

a. The simple cyst, containing a serous or synovial fluid, may occur in any bone, but it is chiefly met with in those of the face, the lower jaw being the most subject to it, and next the upper jaw. In size it may equal a hen's egg, or even exceed it (Dupuytren). By its pressure it produces atrophy of the osseous tissue, and expands the compact tables of the bone to a thin-walled bladder, which crackles under the finger like a piece of parchment. When this layer is also consumed, the cyst protrudes through and beyond the bone, and its wall becomes strengthened by the periosteum, etc.

B. Compound cystoid growths are very rarely seen in bones. Some cases, however, recorded by old observers, undoubtedly belong to this class; especially one or two of those which Lobstein has collected from his own experience and that of others, and has described under the name of osteolyosis.

y. Acephalocysts have been observed in bone eight times. Of these eight cases one, which is preserved in the Vienna Museum, presents considerable interest, from the premises which it affords with regard to the cause of the disease. They have been met with in the humerus, the tibia, the ilium, and the diploe of the skull. In most of the cases recorded by foreign observers, the disease had been developed in consequence of injury. The following is an account of our own case.

The patient, a laborer, aged 42, had, in his youth, suffered from swellings of the cervical and axillary glands; and five years before his death from gonorrhoea and chancre, and consequent bubo. Still later, his penis had been amputated on account of malignant (bösartig) ulcerations; and one year before his death the disease, which was afterwards found in his bones, commenced with pains of a tearing and boring character.

When the body was examined, the left ilium was found converted into a fibrous sac as large as a man's fist, which, besides containing numerous splinters of bone, small and large, sticking in the inner wall of the sac, was also filled with echinococcus-bladders (acephalocysts), varying from the size of a millet-seed to that of a nut. Similar sacs, but less in size, were found also in the pubes, ischium, and sacrum, from which bones they projected into the pelvis. Some of the echinococci were free; but others, especially the smaller ones, were situated either singly or in clusters in the dilated pores and cells of the bare and broken-up pieces of the bone. The bottom of the acetabulum was completely destroyed, and the head of the femur projected into an acephalocyst sac, which occupied its place.

C. Abnormal Fibrous Tissue

To this class belong, a. Fibroid tissue, originally deposited as a product of inflammation or exudation, but arrested in its development into bone; fibroid callus.

B. Fibroid tumors. These occur most in spongy bones, in the articular extremities of long bones, the vertebrae, and the phalanges of the fingers, in the bones of the skull, the lower jaw, and the bones of the pelvis. They sometimes reach a very large size, and distend the bone into a bladder, or so break it up, that it is found scattered in separate fragments through the tumor. The fibroid tumor sometimes has a very dense structure; at other times it is looser, soft, and elastic, and then merits particular notice, inasmuch as it may be easily mistaken in the living subject for other softer - chiefly cancerous - growths; especially if it should have attained a large size, and produced inflammation, sloughing, and ulceration of the integuments by the chafing and pressure which it occasion.

D. Enchondroma

This growth is incomparably more frequent in bone than in any other structure, and presents in the osseous system all those numerous varieties which are incident to it both in its own internal construction, and in the condition of the bone around it.

It is met with chiefly in the bones of the fingers and toes; it occurs also in the ribs and sternum, and has, moreover, been observed in the bones of the skull, the ilium, and the long bones. Its commencement dates mostly from the period of youth, even though it may have first attracted attention by its enlargement at a later period of life: I have, however, seen cases in which there can be no doubt that it had been developed at an advanced period of life. The variety of aggregated enchondroma I have seen combined with an extensive formation of osteophytes.

Like the permanent cartilages, it generally remains for a long time, and even throughout life, in its original condition; sometimes it ossifies, and I have observed this metamorphosis affecting the last-mentioned variety of the disease in a very remarkable manner; it has been already described. Lastly, an entire enchondroma is sometimes involved in inflammation of the surrounding soft parts, and destroyed (wird verjaucht).

E. Osteoid

There can be no question that several of the new growths which occur in bone, though they differ in their nature, may be included under this title. Passing by mere concretions, I may observe, that fibroid growths in bone ossify as well as those in other structures: but to be more particular, a spherical osseous tumor may be developed by the progressive ossification of a newly-formed cartilaginous basement in an old bone; and it may be distinguished from the normal bony tissue by the difference of its elementary structure. A most remarkable specimen of this kind is preserved in the Vienna Museum. It is the skull of a person of 26 years of age, who died suddenly whilst suffering from Exophthalmos. In the anterior fossa of the base of the skull on the left side there is a tumor, nearly as large as a duck's egg, which appears slightly lobulated on its surface, and is composed of a very dense, dull white, bony structure: a portion of it as large as a walnut projects into the orbit, and forms one process with another portion, of about the size of a hazel-nut, which extends into the zygomatic fossa. This mass of bone springs from the diploe of the frontal bone, forces its compact walls asunder, and perforates them on both sides. There are other tumors near it, similar but smaller in size, which spring from the diploe of the frontal, and greater wing of the sphenoid, bones.

A different osteoid tumor may be developed also from the enchondroma at any period of its existence.

F. Cholesteatoma

Cholesteatoma is rarely seen in bone, and I am aware of but one instance, which is in the Vienna collection. It is that of an encysted cholesteatoma, occupying the mastoid portion of the temporal, and the adjoining occipital bone.