There is heat, throbbing, pain, and swelling of the part, sometimes redness of the surface, and great constitutional disturbance; the symptoms and appearances, however, vary much, according to the extent of the joint which is involved. When part of the capsule is affected, the inflammation spreads rapidly over all the surface; the synovial membranes resembling the serous in this respect, as well as in healthy structure and function. Like the serous, too, they are shut sacs, are smooth on their surface, and furnish a secretion, the synovial, for facilitating the motion between opposing surfaces; it is, however, somewhat more glairy than the serous. Neither, in their healthy state, are possessed of much sensibility, nor are ligaments, tendons, tendinous sheaths, and bursæ, which two latter textures resemble in every respect the synovial; when inflamed, they become most exquisitely sensible. The incited action of the bloodvessels is followed by increased discharge, which is less glairy and albuminous, partaking more of the serous character. When the incited action soon terminates, and the activity of the absorbents is diminished, the fluid accumulates within the joint, producing _Hydrops Articuli_. This accumulation of fluid in joints may take place without being preceded by any apparent inflammation, and may remain a long time without any visible change of structure in the membrane. The knee is more frequently the seat of dropsy than any other joint. When the action is more violent, and is not actively opposed, lymph is effused on the inner surface of the membrane, or is deposited amongst the ligamentous and cellular tissues external to the joint, in consequence of which, the membrane and external ligaments become thickened, and of an almost cartilaginous consistence. Serum is effused into the more superficial cellular tissue, filling up the hollows around the joint, concealing the protuberances of the bones, and producing a globular swelling. The articulating surfaces become ulcerated, and matter forms within the capsular ligament; or the pus is deposited exteriorly to the joint, and gradually approaches the surface. But although ulceration is so prone to occur in the cartilages, the synovial membranes do not readily take on this action, unless from the progress of matter, formed within the joint, towards the surface. The synovial lining of the bursæ and sheaths of the tendons are extremely indisposed to ulcerate; and it may be remarked, that, while suppuration without ulceration is common in the synovial membranes, the cartilages, on the other hand, afford frequent instances of ulceration without suppuration, of which more particular mention will be made in the sequel. The cartilage is occasionally swelled and softened where the disease has long existed.