BRODIE, however, holds there is "sufficient to prove that the articular cartilages may be absorbed or ulcerated from the action of their own vessels, and that the ulceration may begin, and frequently does begin, on that surface which is towards the articular cavity. At the same time it is to be observed that in many instances the ulceration begins in another situation, and I have frequently seen the cartilage abraded where it had been in contact with the bone, while on the surface, towards the cavity of the joint, it remained smooth and perfect. Under these circumstances the space formed by the absorption of the cartilage becomes filled up by a vascular substance resembling granulations, and uniting the bone and cartilage to each other. In whatever way the ulceration of the articular cartilages is produced there is this remarkable difference between it and the ulceration of soft parts: suppuration seldom takes place while the ulcer of the cartilage is small, and often the disease proceeds so far as to cause caries of the bones to a great extent without matter being formed in the joint. This circumstance is deserving of notice. It has long been established, that suppuration may take place without ulceration, and it appears that, in this instance, ulceration occurs without the formation of pus." (pp. 116, 17.)

LAWRENCE (a) also says, that " ulceration of cartilage" not only takes place from other causes, but "as an original affection of the joints. Without any disease of the synovial membrane, without the occurrence of any accident or injury, it may commence as a primary or original affection of the joint itself. The ulceration is attended with two circumstances which are very different from those we observe in ulceration of other structures. There is no formation of pus, nor do we ever find granulations produced from diseased cartilages-no attempt at reproduction of the cartilaginous structure. Although ulceration of the cartilages may be in the first instance limited to the cartilaginous structure itself, yet it soon involves other parts of the joint. It extends in the first place to the bony articular extremities, which become ulcerated, and are, in common language, rendered carious: the synovial membrane and external soft parts about the joint become inflamed: small abscesses form and break externally; a succession of these takes place in various parts of the joint, and a number of fistulous openings are established about the joint, giving place to matter, and, in many cases, to carious portions of bone. The ulcerative process often extends to the ligaments that connect the articulations; the consequence of which is, that the bones are no longer retained in their relative positions, but are thrown into certain unnatural directions by the action of the strong muscles of the limb." (p. 483.)

According to KEY's views, the ulceration of cartilages, commonly so called, depends on four conditions, in three of which "the cartilage," he says (b), "is not absorbed per se, but through the agency of a structure, probably evolved for the special purpose of completing that process," and the fourth is "the result of disorganization of texture." The first two forms, viz., "the loss of articular cartilage that attends upon the chronic inflammation of the synovial membrane, and the more active destruction of the articular cartilage that attends acute inflammation of the joint," appear to me simply modifications of the same process by the degree of the inflammatory action, and, therefore, to be considered as one form, either in its chronic or acute stage, as may be, the result of which is the production of a vascular and absorbing membrane from the synovial membrane. The next is "the absorption of cartilage that accompanies strumous disease of the cancellated structure of bone," or that condition mentioned by BRODIE, in which "the cancellous structure of the bones is the part primarily affected; in consequence of which ulceration takes place in the cartilages covering their articulating surfaces." (p. 226.) The consideration of this form must be deferred to Inflammation of the Jointends of Bones. (par. 221-24.) The last condition, much less frequent, is that in which KEY says, "that structure (cartilage) appears to undergo a change in its organization, independent of foreign agency. * *An action altogether different from absorption, and analagous to the softening of the intervertebral substance." To which he applies the term "disintegration, in contradistinction to absorption, the one being a loss of substance from an absorbing action, the other being the result of a disorganization of texture. It is the primary ulceration of cartilage described by authors." (pp. 134, 35.)

Of the absorption of cartilage by a new membrane produced by inflammation of the synovial membrane,

KEY (c) thus speaks:-"In a manner analogous, in many respects, to the process of removing dead bone, does nature achieve the task of absorbing the cartilaginous structure covering the articular extremities of bones. These structures possess but (a) Lectures in Lancet.

(b) Further Remarks on the Ulcerative Process; in Med.-Chir. Trans., vol. xix.

(c) On the Ulcerative Process in Joints; in Med.Chir. Trans., vol. xviii.

a low degree of organization; in their healthy condition they present very few of the characters of animal vitality: they exhibit scarcely any trace of red blood vessels, and, for obvious reasons, their supply of nervous influence is not more than sufficient to connect them with the surrounding structures, as part of a whole. Under disease they exhibit that want of action which might be anticipated from the limited extent of their organization. In acute inflammation of a joint, while the synovial membrane and ligaments are much altered, the cartilage appears unchanged in colour or in texture, and apparently uninfluenced by the increased action going on in the surrounding parts. The cartilage becomes, under disease, softer somewhat in texture; but this change may be as well attributed to the absence of pressure as to the effect of inflammatory action; for healthy joints when kept long at rest are found to undergo a similar change, on their cartilaginous surface, from the want of that pressure to which they have been accustomed, and which may be necessary to the preservation of their due consistence. There are, however, some forms of inflammation under which the cartilage, very early in the disease, undergoes a change of structure: these instances are much less frequent, and may be looked on as exceptions to the ordinary rule." (pp. 216, 17.)

"The progress of ulceration in cartilage covering the ends of bone," continues KEY, "is not uniform in its course. The means by which it is effected vary according to the cause that gives rise to it. It is sometimes the result of acute synovial inflammation, or of a chronic affection of that membrane: it is occasionally found as a primary affection, independent of the other textures of the joint. * * * I am inclined to believe that inflammation of this membrane is the most frequent cause of ulceration of the cartilage. This opinion I have been led to adopt from the examination of a considerable number of diseased joints, in which ulceration of cartilage has been found to exist in different degrees of progress from its most advanced stage, in which the bone has been entirely denuded, to the very incipient abrasion of its surface or margin. The history of some of these cases, together with the morbid appearances, has also satisfactorily proved the existence of a long-continued synovial affection, before any alteration of the cartilaginous surface could have taken place, as the cartilage in some has been quite sound, with the exception of a slight loss of substance at the edge of the bone, where the synovial membrane is reflected from it: while the symptoms of diseased joint have existed for many months, with pain over a large part of the synovial surface, and general swelling of the joint.* **The inflammation of the synovial membrane that leads to ulceration of cartilage in the ordinary strumous affection of joints in the adult, is not, as far as my observation goes, of the most acute kind. ** The less acute forms of the disease, assuming various shades of activity between the chronic and the acute forms, rarely occur for any great length of time without the cartilage participating in the mischief. This may in some measure depend on the peculiarity of those constitutions in which sub-acute inflammation seems to have a spontaneous origin. The knee-joint is most frequently observed to suffer disorganization from this form of inflammation. * * * When the more acute symptoms are subdued (by treatment) the membrane sometimes fails to regain its normal condition, passing into a chronic form of action so slight as to attract but little attention, and often regarded as stiffness that will yield to exercise and passive motion. This slight degree of inflammation that remains often lays the foundation of future mischief, especially if the condition of the patient's health is not adverted to after the acute stage of the inflammation has subsided. The nature of the remedies employed always leaves the patient in a state of weakness and irritability, under which the low degree of action that remains in the joint will be disposed to assume the ulcerative form. *** This state of joint as the disease advances is usually attended with more pain, than when the disease assumes from the commencement the chronic form; the intervals of ease become short and few; and the action goes on with but little interruption to the formation of abscess. In the chronic form of synovial inflammation that occurs in indolent habits of a strumous tendency, especially in persons below the age of puberty, years often elapse before the ulcerative process is completed. The symptoms are proportionally mild in their course. The joint is not much swelled, the general and uniform fulness of the joint, so characteristic, as BRODIE has observed of the most acute forms of inflammation of the synovial membrane, is absent; the joint appears as if the bones themselves were enlarged, an appearance as much produced by the shrinking of the limb above and below the joint as by the swelling of the joint itself. The swelling of the soft parts about the joint depends on the degree of inflammation present in the synovial membrane, and the consequent effusion in the soft parts. In the most chronic forms the bones can almost be felt through their ligamentous investments; in the less chronic forms, when the disease runs its course in a shorter period, there is effusion of albumen in the soft structures surrounding the joint, which increases its volume, pre

venting the bones being distinctly felt, and in some measure altering the form of the joint. (pp. 218-22.)

"The patella and the extremity of the femur are the parts on which the ulcerative process can be best traced, on account of the disease being in these less advanced. In the former bone, the first part that commonly gives way to ulceration is the margin of the cartilage, where the synovial membrane is reflected from it. At this point sulci of different depths are formed, which cannot be always distinguished until the thickened edge of the synovial membrane is raised. The ulcerated surface sometimes exhibits parallel vascular lines, verging towards the centre, and having their origin from the synovial membrane. The synovial membrane at this part, if the vessels are well filled with fine injection, appears highly vascular and fringed, or villous, like a mucous membrane. This increased vascularity is particularly noticeable at the edge of the membrane and in those portions of the fringed margin that correspond to the ulcerated surface of the cartilage; the other parts of the synovial membrane have their vascularity but slightly increased. This highly vascular fringe of membrane is a newly organised, and will be found in some parts to be a superadded, structure, for the purpose of producing ulceration of the contiguous cartilage. It may, when recently formed, be raised in some parts from the synovial membrane, but is found to adhere very slightly to that part of the cartilage where ulceration is going on; this adhesion is not perceived unless the joint is opened with great care. *** The process, therefore, by which the ulceration of cartilage is in this case effected, is analogous to that by which the sequestrum of the cylindrical bones under necrosis takes place. Indisposed to ulceration, from the low degree of its organization, it is acted upon by the newly organised synovial surface, which is rendered highly vascular, and by means of its villous processes forms a groove in the edge of the cartilage, thus commencing the work of destruction. The cartilage at the edge is sometimes entirely destroyed, so as to lay bare the bone, in which case vascular granulations also arise from the surface of the exposed bone, and assist the membrane in the work of absorption. This, however, is more usually observed in the most acute form of inflammation. In the more chronic form, the vascular fringe of synovial membrane contracts adhesion to the surface of the cartilage in which ulceration is going on, and gives rise to the formation of a new membrane, which spreads gradually over the surface of the cartilage. A diseased joint is hardly ever examined without exhibiting one or more of the bones partly covered with this pulpy membrane. When injected, its vascularity is found to vary according to the activity of the inflammation in the joint; when first formed it exhibits considerable vascularity during the ulcerative process: when the cartilage has been wholly absorbed, and the ulcerative process has been checked by the inflammation being arrested, this membrane then serves another purpose; it becomes the medium of union between opposed surfaces of bone, or the means of anchylosis. Long after all inflammation has subsided, one of the condyles of the femur is often found adhering to the tibia by means of this membrane, which appears white and ligamentous; a layer of cartilage often remaining between the membrane and the bones, as if the process of ulceration were arrested." (p. 223-226.)

GOODSIR (a) holds with KEY in the deposit from the synovial membrane being the cause of ulceration in cartilage; for, as "in the thin articular cartilages of the adult human subject, few or no vessels can be detected, it is evident that in the process of ulceration in cartilage, it cannot be the usual blood-vessels of the part which are the active agents, still less likely is it that lymphatics, the existence of which has never been asserted in this texture, are the absorbing instruments." He then proceeds :-" If a thin section, at right angles, be made through the articular cartilages of a joint, at any part where it is covered by gelatinous membrane in scrofulous disease, or by false membrane in simple inflammatory condition of the joint, and if this section be examined, it will be found to present the following appearances. On one edge of the section is the cartilage unaltered, with its corpuscles natural in position and size. On the opposite edge, is the gelatinous, or false membrane, both consisting essentially of nucleated particles, intermixed, especially in the latter, with fibres and blood-vessels; and, in the former, with tubercular granular matter. In the immediate vicinity, and on both sides of the irregular edges of the section of cartilage, where it is connected on the membrane, certain remarkable appearances are seen. These consist, on the side of the cartilage, of a change in the shape and size of the cartilage corpuscles. Instead of being of their usual form, they are larger, rounded, or uniform; and, instead of two or three nucleated cells in their interior, contain a mass of them. At the very edge of the ulcerated cartilage, the (a) The Process of Ulceration in Articular Cartilages; in his Anatomical and Pathological Observations. Edinburgh, 1845. 8vo.

cellular contents of the enlarged cartilage corpuscles communicate with the diseased membrane by openings more or less extended Some of the ovoidal masses in the enlarged corpuscles may be seen half released from their cavities by the removal of the cartilage; and others of them may be observed on the substance of the false membrane, close to the cartilage, where they have been left by the entire removal of the cartilage which originally surrounded them. If a portion of the false membrane be gradually torn off the cartilage, the latter will appear rough and honeycombed. Into each depression on its surface a nipple-like projection of the false membrane penetrates. The cavities of the enlarged corpuscles of the cartilage open on the ulcerated surface by orifices of a size proportional to the extent of absorption of the walls of the corpuscle, and of the free surface of the cartilage. The texture of the cartilage does not exhibit, during the progress of the ulceration, any trace of vascularity. The false membrane is vascular, and loops of capillary vessels dip into the substance of the nipple-like projections which fill the depressions on the ulcerated surface of the cartilage; but, with the exception of the enlargement of the corpuscles, and the peculiar development of their contents, no change has occurred in it. A layer of nucleated particles always exists between the loops of capillaries and the ulcerated surface. The cartilage, where it is not covered by the false membrane, is unchanged in structure. The membrane generally adheres with some firmness to the ulcerating surface; in other instances it is loosely applied to it; but, in all, the latter is accurately moulded to the former. (p. 17–19.)

The view given by KEY, of the usual mode in which cartilage is absorbed, or as it is commonly called, ulcerates, is in the main similar to that held by WILSON, but more fully and more satisfactorily developed. Its correctness I cannot doubt, for I have seen it, I think more than once or twice, from the first commencement, in which, on carefully lifting up the new membrane, its perfect impress is perceived upon the cartilage, varying in depth and extent according to the thickness and size of the membrane, till the entire depth of the cartilage is removed and the membrane comes in contact with the bone, the articular surface of which is also destroyed either by it or by simultaneous inflammatory action set up in the cancellated structure of the bone. The preparations to which I allude are in St. Thomas's museum, and some of the patients were under my own care.—

J. F. S.

"When suppuration," KEY continues, "follows acute inflammation, from a wound of the synovial membrane, the latter undergoes that change which enables it to perform its new function. The surface becomes highly vascular, and, in most parts, covered with a new deposit of adhesive matter, which adheres firmly to the synovial membrane. The new surface is irregular, wanting the polish of the original membrane, and appears in many parts villous, or furnished with vascular fringed projections. In a joint thus far advanced in disease, the only mode of arresting the disease, or of repairing the mischief occasioned by the inflammation, consists in anchylosis. To this end, the removal of the cartilage is an essential step; and it would appear that the office of removing it devolves on the inflamed synovial membrane. The cartilage, under these circumstances, is not only eroded at the edge where the synovial membrane is reflected upon it, but grooves and indentations may be traced in various parts of it, having no connexion, as in the progressive strumous form of ulceration, with the edge of the synovial membrane, and not showing any indications of a new membrane forming on its surface. The means by which this ulceration is effected appear to be the newly organized surface of the synovial membrane in contact with the parts in which absorption is going on. To those who will carefully examine joints in this condition, the evidence of this will, I think, be sufficiently conclusive. The absence of all action in the cartilage, and the total want of vascularity in those parts where ulceration appears to be most active, were the circumstances that first led me to look for some agent in the work of ulceration. The ulceration evidently begins on the surface of the cartilage, and not on that side next to the bone. It presents merely an eroded surface; there is no disorganization of its texture in the parts where absorption is about to take place; there is no previous degeneration of the cartilage into its primary fibrous structure, as may be seen in other forms of ulceration; but the cartilage seems to have lost part of its surface, as if it had been dug out, the remaining part appearing healthy, and presenting no trace of increased vascularity. The grooves are found only in those parts of the cartilage that happen to be opposed to the fringed and vascular synovial membrane; and these highly organized portions of the membrane may be seen to be closely adapted, and even to fit into the grooves in the cartilage. Those parts of the cartilage that happen to be in contact with another cartilaginous surface present no signs nor trace of ulceration, but appear to the eye perfectly healthy, and in texture firm. The process exhibits the el est analogy to that by which nature removes dead bones; the same inactivity or pas

sive condition of the parts absorbed; the same suppurative action from the vascular granulation; and a similar degree of vascularity bestowed upon the newly organised structure which has to perform the office of absorption. It is not, however, in every instance of suppuration in a joint, even where this villous membrane is found, that ulceration of the opposite cartilage is to be looked for as an uniform occurrence; for strumous joints are occasionally examined, in which the synovial capsule has been for many months distended with purulent secretion, and the synovial membrane covered with flocculi hanging into the joint, without a trace of ulceration in the opposite cartilaginous surface. This exception rather favours the view which I have advanced of the ulcerative process in the case of suppuration from wound. The condition essential to the act of absorption is here wanting. There is not a wound or opening by which the pus can escape as fast as it is secreted: it consequently collects in the cavity of the joint, and, by distension, prevents the membrane coming in contact with the cartilage; and the villous projections from the membrane, even when the vessels are well filled with fine injection, do not exhibit that degree of vascularity which is so clearly developed when ulceration of the cartilage takes place. (p. 234-37.) Nature, it seems, does not often adopt this mode of removing the cartilage. It is only in the acute form of inflammation, as in wounds of joints, that I have observed it. The process of removing the cartilage appears at all times, and under all circumstances of disease, an object that she endeavours to accomplish; while the cartilage remains entire, anchylosis, the natural cure in some forms of diseased joint, cannot be effected; and, therefore, we may often observe ulceration of cartilage going on very early in those diseases that, forming some defect in the patient's constitution, cannot be arrested without anchylosis. (pp. 239, 40.) BRODIE (a), however, still considers that "the explanation which KEY has offered does not admit of a general application, and that the absorption of the cartilage, commencing on the surface towards the cavity of a joint, may take place under such circumstances, that it cannot be supposed to be the result of any other agency than that of the vessels of the cartilage itself. (p. 331.) In speaking of ulceration of the articular cartilages, as a consequence of inflammation of the synovial membrane, I have not endeavoured to explain the exact nature of the process by which such ulceration is effected, and simply for this reason,—that I have not been able completely to satisfy my own mind on the subject. There can be no doubt that, in many instances, ulceration begins at the margin of the cartilage, where the synovial membrane is reflected over it from the neighbouring bone, or from the inter-articular ligaments, where such ligaments exist; but it may still admit of a question, in what manner the ulceration is accomplished; whether it be from the inflammation extending directly to the cartilage itself, or to the bone first, and the cartilage afterwards; or whether, according to the views entertained by Mr. KEY, the latter, being altogether in a passive state, becomes absorbed by the action of the vessels of the fringed processes of the synovial membrane lying in contact with it. But there are other cases of inflammation of the synovial membrane, in which ulceration begins in the centre of the cartilage, so that none of these hypotheses afford any reasonable explanation of it. It seems not improbable that, in some of those cases which are usually regarded as examples of simple inflammation of the synovial membrane, the inflammation may not have been confined (even in the first instance) to this individual part, but may have begun simultaneously in all the textures of the joint. This is in conformity with what is observed to happen occasionally in the eye and other organs; and, under such circumstances, it is no more than might be expected, that, as the inflammation subsides, the cartilage should ulcerate either in the centre or in some other part of its surface. Nor is this a merely speculative opinion; at least I am much mistaken if it be viewed in that light by any one who, after having perused the history of the following case, considers what would probably have happened if the patient had not died of another disease before there was time for the disease in the joint to have run its course. A gentleman, about twenty-five years of age, had laboured for several years under a disease of the brain, in consequence of which he had been in a state of complete helplessness and imbecility. In the summer of 1820 he became indisposed otherwise: there was a cluster of enlarged glands in the left groin, and a purulent sediment was deposited by the urine. was now desired to see him in consultation with Dr. MATON, who was his ordinary medical attendant. Soon afterwards, it was observed, that there was a general tumefaction of the left thigh and nates, and the patient complained of pain in certain motions of the limb. Under the treatment employed, the tumefaction subsided; but, immediately afterwards, a violent attack of diarrhoea took place, under which he sunk, and died on the 29th July. On examin(a) Additional Notes on Ulceration of Cartilage; in the Third Edition of his book on the Diseases of Joints, 1834.