=Symptoms.= The symptoms usually develop gradually and without lameness, but sometimes declare themselves more rapidly with lameness, accompanied by marked sensitiveness on palpation. At first the hock shows a generalised doughy swelling, soon followed by dilatation of the articular synovial sac. Somewhat later four different swellings appear—two in front, separated by the tendons of the common extensor and flexor metatarsi, and two at the back, extending inside and outside to the flexure of the hock. =Diagnosis.= The only precaution required in diagnosis is to avoid confusion with articular rheumatism. =Prognosis.= The prognosis is rather grave in the case of working oxen, and even of bulls; often slaughter is preferable to treatment. =Treatment= differs in no respect from that of distension of the stifle joint. In young bulls aseptic puncture and drainage of the joint, followed by the application of the actual cautery, probably give the best results. DISTENSION OF TENDON SHEATHS IN THE HOCK REGION. Like the preceding, this condition is rarely seen except in bulls and working oxen. It is characterised by dilatation of the upper portion of the tarsal sheath, one swelling appearing on the outer side, the other on the inner. The differential =diagnosis= is based on the position of these synovial sacs, which are quite close to the insertion of the tendo-Achillis, and on the absence of any swelling in front of the joint. =Treatment= is identical with that indicated in the last condition. Massage and cold water applications should be employed at first, to be followed by aseptic puncture and withdrawal of fluid, supplemented if necessary by firing in points. DISTENSION OF THE SYNOVIAL CAPSULE OF THE KNEE JOINT. [Illustration: $1] [Illustration: $1] This is one of the rarest conditions now under consideration, because the synovial membranes of the knee joint are everywhere strongly supported by very powerful ligaments. The synovial capsules of the carpo-metacarpal and inter-carpal joints are incapable of forming sacs of any size. On the other hand, the radio-carpal may become moderately prominent in front, especially towards the outside above the superior carpal ligament. When weight is placed on the limb, the excess of synovia is expelled from the joint cavity towards this little sac, which then becomes greatly distended. If, on the other hand, the knee is bent, the sac shrinks or disappears. =Treatment.= Treatment is restricted to the application of a blister or to firing in points. DISTENSION OF THE SYNOVIAL CAPSULE OF THE FETLOCK JOINT.