+Treatment.+ Rest and wet dressings generally suffice to effect restitution in a few weeks. +Penetrating.+ Should the joint be injured by violence so that there is a loss of continuity of the tissues leading into the joint proper, there is every probability of infective material gaining entrance. These are serious accidents, though restoration of an efficient joint is possible, but when improperly treated or neglected, local destruction, or even loss of life may occur. Penetrating wounds of joints usually occur in consequence of accidents with firearms, sharp tools, or falling upon sharp objects. Frequently, penetration of a joint follows suppuration in the immediate neighborhood. +Symptoms.+ The extent of the injury, the particular joint involved, and the nature of the vulnerating body will affect the train of symptoms. An escape of synovial fluid, pain and some swelling will occur even with a very small penetration. Should the joint escape infection, the synovitis quickly subsides and recovery takes place with little or no impairment of the functional value of the part. The opening in the capsule closes, the extravasated blood is absorbed and the synovial surface is again smooth. If, however, the wound has been inflicted with an unclean instrument, or if at any time before healing it becomes septic, a very different and graver condition obtains. +Septic Arthritis.+ Infection with bacteria of suppuration, chiefly the staphylococcus albus or the streptococcus pyogenes, produces an acute arthritis which frequently, despite the most careful treatment, will result in the destruction of the joint, and not seldom in the loss of life. The infection may occur in one of several ways: (1) directly through a dirty instrument, or the lodgment of infective material in the tract leading to the joint cavity; (2) by the extension of a suppurative process, either of the bones or soft tissue adjacent; or, by (3) the deposition into the joint of infective organisms circulating in the blood stream. +Symptoms.+ However produced, large numbers of organisms are present and a high grade of inflammation ensues. An abundant amount of pus is soon formed; the synovial membrane, the bone ends and the joint capsule are actively inflamed, and soon become disorganized. Perforation of the capsule is followed by infection and suppuration of the tendons and other structures about the joint, which soon affects the superficial structures and forms an opening through the skin. The pain is intense, generally worse at night; the swelling is great and fluctuation is distinct; the skin is red and hot, and the parts above and below are edematous. Any attempt at motion increases the suffering.