The morbid anatomy of simple chronic articular rheumatism will vary with the severity and duration of the disease. The alterations are such as chronic inflammation of a non-suppurative character might be expected to produce in the joints by one who had learned those characteristic of acute rheumarthritis. In the simple chronic form the proliferating process involves chiefly the synovial membrane, the capsular and other ligaments, and the periarticular tissues; to a less degree the cartilages, and to a much less degree, and exceptionally, the osseous surfaces. The synovial membrane is thickened, slightly injected, and its fringes hypertrophied and more vascular than normally. Little fluid usually exists in the joint unless during an exacerbation, when a moderate amount of thin, cloudy serum may be present; generally only a trace of thick, turbid fluid, containing oil-globules, and in severe cases débris of the cartilages, but no pus, is found. The fibrous capsule and ligaments become thickened, dense, and stiffened by hyperplasia; and sometimes the adjacent tendons and their sheaths, the fasciæ and aponeuroses, undergo similar alterations, so that the movements of the joints become seriously interfered with. In some cases this irritative hyperplasia specially involves these periarticular fibrous structures, and these, undergoing retraction, produce marked deviations, subluxations, and deformities of the articulations very like those observed in rheumatoid arthritis, although the osseous components of the joints are unaffected. Jaccoud gave to such cases the title of chronic fibrous rheumatism.[211] It is worth noting that Jaccoud's, Charcot's,[212] and Rinquet's[213] cases of so-called "chronic fibrous rheumatism" developed out of acute articular rheumatism, while Besnier's was primarily chronic. In simple chronic rheumatism, if protracted, the cartilages also proliferate, lose their semi-transparency and polish, and become opaque and white; they are often rough and traversed by fissures, and occasionally present erosions; and these erosions {71} are either naked or covered with a layer of newly-formed connective tissue, which may occasionally produce fibrous adhesions between the articular surfaces. Points of calcification occur in the cartilages and tendons in very chronic cases. Instances are observed in which the bones exhibit, to a slight degree, the alterations found in rheumatoid arthritis, and are probably transitional between the two affections. The muscles which move the affected articulations in severe cases are often atrophied, and the wasting imparts to the joints an appearance of considerable enlargement. [Footnote 211: Vide Jaccoud, _Clin. Méd. de la Charité_, 23e Leçon, Paris, 1867.] [Footnote 212: Besnier, _Dictionnaire Encyclopéd., etc._, t. iv., p. 680 _et seq._] [Footnote 213: _Du Rheum. Artic. Chronique, etc._, par Martial Rinquet, Thèse, Paris, 1879, pp. 28-33.]