=Diagnosis.= Provided that the examination is made soon after the occurrence of the accident, little difficulty will be found in coming to a conclusion, but the diagnosis necessitates more care when examination is deferred for two or three days, because extensive effusion then exists. Luxations or subluxations of tuberculous origin are generally consecutive to old-standing destructive tuberculous arthritis. =The prognosis= is grave—firstly, because reduction is difficult; and, secondly, because it is often impossible to maintain the reduction and to preserve complete immobilisation of the injured joint. =Treatment= should not be undertaken except in young animals which have not yet attained full development. In attempting to reduce outward or inward luxation of the tibia the animal should be cast on the side opposite to the lesion. Counterextension is practised by passing a length of webbing around the limb in the region of the groin; extension in the direction of the length of the femur by means of a loop of webbing fixed to the cannon bone: the operator uses both hands in endeavouring to replace the head of the tibia. In forward luxation of the tibia counter-extension is effected by means of a loop of webbing passed above the hock and drawn forward. Extension is made backwards in an oblique direction, the operator again being left free to effect reduction with both hands. Reduction of backward luxation of the tibia is still more difficult, in consequence of the contraction of the mass of muscle at the back of the thigh. Plaster bandages are the most convenient means of immobilising the parts after reduction. LUXATION OF THE SCAPULO-HUMERAL JOINT. This luxation, like that of the femoro-tibial articulation, is exceptional. It may assume one of two forms, depending on whether the head of the humerus is displaced inwardly, or towards the back of the glenoid cavity; but as a rule luxation occurs inwardly. Forward luxation of the head of the humerus is almost impossible, in consequence of the resistance offered by the tendons of the flexor brachii and antea spinatus muscles. Similarly, luxation outwards is very difficult, the tendon of the postea spinatus being very powerful and offering enormous resistance. Inwardly, on the other hand, the insertion of the subscapularis is much less powerful, and there is no real opposition to movement of the head of the humerus.