THE MORBID ANATOMY OF ACUTE AND SUBACUTE ARTICULAR RHEUMATISM.--Although opportunities of ascertaining the conditions of the articulations in acute articular rheumatism are rare, yet it is now established that the process is an inflammation involving chiefly the synovial membrane, and to a less degree the cartilages, ligaments, tendinous sheaths, and in some cases even the bones and periarticular soft parts. The synovial membrane is more or less injected and reddened diffusely or in patches, especially where it forms fringe-like folds and at its line of union with the cartilage. It is somewhat thickened, opaque, and devoid of its satin-like lustre, and in somewhat protracted cases covered here and there with a thin, easily detached neo-membranous formation. Within the articulations will be found from a few drops to one or two ounces of a viscid, pale, citron- or reddish-colored fluid, like synovia, but more fluid, and generally turbid and containing transparent or semi-opaque gelatinous masses or albumino-fibrinous flocculi. The {47} microscope reveals in the effusion large detached spherical epithelial cells in various stages of germination or of fatty degeneration, and a variable number of red blood-corpuscles and pus-cells. Very exceptionally, the effusion is mixed with more or less true pus. In two out of the eight fatal cases reported by Fuller, in which the joints were examined, pus in moderate quantity was found along with other products in some, but not in all, of the inflamed articulations, and one of them was complicated with erysipelas, the other with sloughs over both trochanters. In very severe forms complicated with hemorrhagic tendencies the inflammatory products have contained a large proportion of blood. Cornil et Ranvier[118] insist that even in slight cases of rheumatic arthritis the diarthrodial cartilage constantly suffers changes arising from nutritive irritation and proliferation of the cartilage-cells. At first the cartilage loses here and there some of its polished hyaline appearance, and the microscope reveals a finely-striated condition of its structure which gives it a velvety aspect. When the inflammation has been more severe and of longer duration, so that the deeper layers have been involved, the unaided eye will perceive local swellings in which the natural elasticity and resistance of the cartilage are impaired, and its surface is fissured or villous-like in appearance. "In certain rare cases of mono-articular acute arthritis true ulcerations of the cartilage are observed." [Footnote 118: _Manual d'Histologie pathologique_, Paris, 1869, 406.]