which first exists in the embryo, but continues without ceasing to reproduce this embryonic structure." 127.

From the microscopic development of enchondroma, M. Müller passes to the duration and termination of enchondroma.

The great length of time that these tumors may exist, is shewn by the history of many cases of this disease which have been erroneously regarded as cancerous. M. Müller refers to several recorded cases in proof of this. In all these cases, the long time, often fifteen or eighteen years, occupied by the disease in its development, and the absence of dangerous symptoms during that period, are very striking. All writers too, concur in representing the development of these tumors as being unattended by much pain. So that enchondroma may continue long, occasion little suffering, and give rise to no degeneration of the superincumbent parts.

But, when inflammation is set up in the tumor, it becomes painful, and bursts. The distention of neighbouring parts, and accidental injury to the enormous tumor bring on, in the course of time, inflammation of it and of the neighbouring textures; inflammation is followed by suppuration, the tumor itself discharges sanies, and the bones, the proper structure of which is already destroyed, become necrosed. Such was the state of the disease in the cases described by Mery and Scarpa.

If the part affected by the tumor is amputated, the disease does not return; but if, after the tumor has burst it still remains in connexion with the body, it may, like every extensive local disease, bring with it the ruin of the whole constitution.

6. Nature of Enchondroma.

It has been already stated that enchondroma consists mainly in the formation of cartilage resembling the primitive form of that substance in the embryo. Its causes are partly local, partly general.

Local Causes.-These may be stated, with great certainty, to be serious injuries to the vitality of the bones, and, in many instances, mechanical violence. This is confirmed by the cases already related, and will be found to be no less substantiated by the histories of other tumors which older surgeons have written, and in which, though the names applied to them are often very various, yet the characteristic features of enchondroma may be easily distinguished.

Severinus quotes a case from Nicolaus Larcho, in which the tumors had appeared in consequence of the bite of a pig, while the patient was young; and in the cases of Schaper, Otto, Klein, and Ph. v. Walther, the disease was referred to a bruise.

General Causes.-In some instances no local causes can be made out, and there is strong evidence of the existence of some powerful general one. A case of Professor Pockels is in point. The tumors of the metacarpal bones and phalanges of the fingers had formed not on one hand only, but there was a commencement of the same disease in the other hand; and the most singular fact of all was, that the feet shewed a disposition to become the seat of the same morbid procees. The pathological changes in the feet and in one hand were but slight, and did not occasion inconvenience, but

the other hand was amputated. The disease did not return; the patient is still alive; his hand and feet are in the same state as before, and probably there is nor much reason to dread the further development of the disease, since it had begun in the earliest infancy of the patient, and had progressed very slowly. Ruysch, likewise, has described some cases in which tumors grew from the fingers and metacarpal bones of both hands, and from the toes of both feet.

M. Müller thinks this general cause akin to scrofula. Both diseases are constitutional, but in no way related to carcinoma, and both are most active during childhood. The observations which have already been adduced suffice to prove that enchondroma occurs most frequently during childhood. Most of the persons in whom it was seen were young men and boys, in whom it had arisen at a very early age. In after-life the general predisposition to enchondroma seems to be extinguished, just as is the case with scrofula. The tumors, which are the effects produced by the previous disease, continue to exist and cannot be removed; but in the adult, after the diathesis has ceased, they continue as merely local affections, which, therefore, do not return after amputation. Yet there are distinctive differences between enchondroma and scrofula, for the affections of the bones in the latter are well known and peculiar, nor do scrofulous growths and tubercles occur in enchondroma. The cause of enchondroma, says our author, seems to consist rather in a peculiar formative process in the osseous system, in consequence of which, especially when local injuries have been inflicted on the bones, cartilage, in its primitive embryonic state, is developed, and continues to be formed without ever attaining to consolidation or perfect organization. The natural tendency of the part to ossification, and the influence of the whole organism, are unable to control the growth of enchondroma, which is produced by the innate vitality of the cartilage cells, and their unceasing multiplication. Other alterations of the bones are very rarely combined with enchondroma; indeed, the only instance of it with which the author is acquainted, is that of a hump-backed man, whose case Severinus has related.

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Enchondroma has figured under various names. It has been successively 'Spina Ventosa," (one of many affections lumped together under that ridiculous denomination,)—" Atheroma Nodosum,”- Osteo-Steatoma,”"Osteo-Sarcoma." Otto has confounded it with cancer of the bones, how erroneously the following cheering statements will shew;—

"The amputation of enchondroma is almost invariably successful, as in the cases of Severinus, Mery, and Scarpa, in the two cases related by Ph. v. Walther, in the two which occurred to Klein; in the case of enchondroma of the tibia, the preparation of which is now in the Museum of St. Bartholomew's Hospital; in the case observed by Professor Pockels; and in those which came under the notice of Professor v. Graefe, the preparations illustrating which are now in the museum at Berlin. Of thirty-six cases, the histories of which have been ascertained by the author, two only had a fatal termination: in one of these cases, the tumor, which was situated on the base of the skull, encroached upon the cavity of the cranium, as well as on that of the nose, and proved fatal, owing to its situation. The second case has reference to an enchondromatous tumor of the thigh bone, which is now preserved in the museum of Guy's Hospital, and is numbered 666* in the catalogue. In this instance, the tumor, which probably brought on death by the loss of the fluids which it occasioned, was removed from the body of the patient after he was dead."

7. Differences between Enchondroma and other Tumors of the Bones. Enchondroma has no resemblance in structure to schirrhous and medullary tumors of bones, their basis being albumen, and that cartilaginous mass, which, when boiled, yields chondrine, being absent.

If fungus medullaris is developed in the interior of a bone, it neither perforates it nor expands it in a spherical manner. It is only in very rare cases of medullary sarcoma that real expansion of the bones takes place. If fungus medullaris is developed on the surface of a bone, it often contains in its interior delicate acicular, or lamellar spiculæ, which shoot from the surface of the bone. In cancer alveolaris, cavities may be observed filled with a transparent jelly; but this structure differs both microscopically and chemically, and, when boiled, yields no gelatine.

"The bones," continues M. Müller, "are subject to another fungous growth, which differs not less widely from enchondroma, and resembles it only in its curability by amputation. The author had an opportunity of studying the characters of this growth, the tumor fibrosus s. desmoides, on a hand which was extirpated with perfect success, by M. v. Graefe. The tumor projected from several of the metacarpal bones, both towards the palm and towards the back of the hand, and presented a lobulated surface and a firm tendinous structure in its interior. When divided, it shewed that white and perfectly fibrous structure whence the tumor derives its name, and which similarity to the glistening satinny tissue of the aponeurosis is characteristic of the desmoid growths. Under the microscope it displayed layers of fibres intertwined, without any trace of cavities or corpuscules. Its base was seated on the surface of the metacarpal bones, from the periosteum of which it was developed; while the bone beneath remained undestroyed, and only slightly rough, as it always is in the neighbourhood of tumors. The arteries of the palm, the muscles, and tendons, ran in the form of an arch over the tumor. The museum of St. Bartholomew's Hospital contains a specimen (Morbid Preparations, first series, No. 148, 149,) of this disease in the substance of the lower jaw. The tumor had developed itself in the interior of the bone, and likewise on its surface."

Enchondroma cannot be confounded with the osteöid, or purely osseous tumor of bone.

But there are other growths, curable by amputation, though often confounded, under the names of osteo-sarcoma and osteo-steatoma with cancer of bone. That form of morbid growth called osteosarcoma, which is not rare in the bones of the face, and particularly in the lower jaw-bone, is a fungus of a peculiar nature, curable by amputation. Its substance never resembles cartilage, is of a greyish white colour, of an albuminous nature, and cannot be resolved into gelatine by boiling. Examined under the microscope, it presents a structure composed of minute cells furnished with nuclei, or else a soft tissue made up entirely of caudate corpuscules, whose linear arrangement gives it a fibrous appearance. These osteosarcomatous growths are sometimes composed entirely of an albuminous substance, but in other cases they yield some gelatine after long boiling. It is moreover, far from an easy matter to distinguish between these growths and those tumors of the bones which are really of a cancerous nature. This latter is an important observation, and should not be forgotten by those who affect the possession of certain means of diagnosis between the malignant and the non-malignant tumors of the facial bones.

Expansion of the bones is sometimes occasioned by the development within their substance of compound cysts, or of hydatids. These constitute a destructive disease, which sometimes implicates a great part of the osseous system. Hydatids are formed in the medullary tissue of the bones, and in other cases they do not produce this effect. The spongy bones, as those of the pelvis, or the ribs, are most subject to expansion; and when it does take place, the hydatids are usually found lying in a soft bed abounding in fat, which is a growth from the medullary texture; while the osseous tissue is absorbed, and forms only fragments here and there in the interior of the tumor. The shell of the bone becomes distended in a spherical manner, as in enchondroma. The disease, as might be expected, renders the bones very liable to fracture, and it often leads to a fatal result.

M. Müller devotes a section to the cases of enchondroma on record, and to the specimens contained in anatomical museums-a very useful section, and we recommend it to the reader. We have not, however, space, nor is it necessary for our purpose to notice it. We therefore pass to:

II. ADIPOSE TUMORS.

The cells of adipose tissue are shut sacs, within which the fat is contained. In most animals these sacs are round, but in some, as the sheep and ox, they have a polyedrous form. It is more difficult to detect the nucleus in the wall of adipose cells, than in cells of other tissues; but, even in them, Schwann has demonstrated the existence of nuclei.

Morbid adipose tumors are repetitions, more or less modified, of normal adipose tissue. Some are made up of ordinary fat, such as is found in the healthy adipose tissue of the human subject, while others contain likewise cholesteatoma, and may be distinguished by their laminated structure.

M. Müller divides adipose tumors into three classes:-The varieties of lipoma form the first; adipose cysts the second; and the laminated fatty tumor the third. In lipoma the fat is contained in ordinary adipose tissue, and is consequently separated into innumerable isolated compartments by the walls of the contiguous cells. In adipose cysts, the fat is not distributed through small cells, but is contained, partly in a fluid state, partly in the form of fat globules, in the interior of a larger sac, which is generally furnished with thick membranous parietes. In the former, the production of the new fat takes place just as in the healthy body; while in the latter a single fat cell appears to become predominant, and, its walls being thickened, it constitutes an independent cyst.

1. Lipoma.-Most specimens of lobulated lipoma resemble in structure ordinary adipose tissue; their cells are of a round or oval shape, and the only distinction between the two consists in the former being made up of a mass of these adipose cells, enclosed by an investment of thickened cellular tissue, while the different lobuli are separated from each other by thinner membranous septa.

A. Lipoma Simplex, to which the name lipoma is usually applied. These growths seem capable of being formed in any part where there is cellular

tissue. In Meckel's museum at Halle, the author saw a small adipose tumor which was situated between the optic nerve and eminentiæ candicantes.

B. Lipoma Mixtum.-In this case, the interstitial cellular tissue of the adipose tumor is greatly developed, and forms strong membranous septa, which intersect its substance, and thus give it a much greater degree of firmness than is possessed by simple lipoma. Hitherto the author has met with but two specimens of this form of tumor; once in the spermatic cord of a man, and once between the muscles of the thigh; and in this latter case the tumor had acquired an extraordinary size.

c. Lipoma Arborescens.-This structure consists of arborescent productions, entirely composed of adipose tissue. Growths of this sort occur in the joints, especially in the knee joint, where they spring from the free portion of the synovial membrane. In this situation they are covered by a prolongation of the synovial membrane, and hang loosely into the cavity of the joint, forming arborescent tufts, somewhat swollen at their extremities.

2. Adipose Cysts.

The ovaries are the most frequent seat of this disease, in which fat, partly in a fluid state, partly in the form of globules and free from adipose cellular tissue, is contained in a large cyst, with dense parietes. In addition to fat, these cysts usually contain hair, either loose within their cavity, or proceeding from their walls; each hair springing from a distinct follicle. In birds, feathers are found in these situations. Gurlt regards the fat in these hair-containing cysts as analogous to that which is formed by the sebaceous follicles of the cutis, and poured by them into the hair follicles. The sebaceous follicles of the skin may themselves become converted into cystoid tumors, and to the accidental occlusion of their orifices many encysted tumors owe their origin. This fact had been rendered probable by M. v. Walther and Sir A. Cooper; and in one instance the author met with a decisive proof of its truth. In an individual, all the sebaceous follicles of the skin of the nose bad become extremely enlarged, and one was converted into an encysted tumor eight lines in diameter. Microscopic corpuscules of irregular polyedrous shape, and resembling epidermoid or epithelium cells, except in being destitute of nuclei, formed the contents of these cysts. These corpuscules are probably produced in a manner similar to epithelium cells.

3. Laminated Adipose Tumor-Cholesteatoma.

This is a non-lobulated tumor, composed of concentric layers of polyedrous cells, which have a lustre like mother of pearl. It is of the consistence of tallow, and is usually invested with a thin membrane which forms a complete cyst. The fat which it contains is not found exclusively within the cells, but is likewise deposited in their interstices. This form of adipose tumor, was formerly but little, if at all known; and M. Cruveilhier was the first who examined its nature with the attention which it deserves. M. Müller refers to growths described by Dr. Merriman, M. Lepestre, M. Cruveilhier, and M. Dupuytren, which he regards apparently with justice as