Inspection discovers a depression where the great trochanter should be. On applying the open hand over the hip joint, whilst an assistant who grasps the pastern moves the limb in different directions, one can feel and hear, in spite of the mass of muscle covering the part, a modified crepitation due to sero-sanguinolent effusion in and around the joint. This crepitation can also be detected by pushing the hand as high up as possible on the internal surface of the thigh, and thus exploring the neighbourhood of the luxation. =Diagnosis.= The position which the animal assumes when one endeavours to make it rise is characteristic. Diagnosis of progressive luxation, however, is more difficult. =Prognosis.= The prognosis is extremely grave; for, even though reduction can be effected, one is practically unable to ensure that the parts shall remain in position. =Treatment.= Treatment comprises reduction of the luxation and fixation of the parts. Reduction can be effected without very much difficulty by casting the animal on the affected side, placing a block of wood, or a pail, between the thighs, and manœuvring the limb in the desired direction. As, however, subluxation is the condition most commonly seen, there is frequently no reduction to effect. Moreover, fixation of the joint after reduction is almost impossible in such heavy subjects, and luxation is very liable to recur. From an economic standpoint, slaughter is advisable or imperative. LUXATION OF THE PATELLA. Luxation of the patella is not uncommon in working oxen, and is occasionally seen in cows as the result of a slip when entering or leaving the byre, the reason being the peculiar anatomical arrangement of the femoro-patellar articulation. The internal lip of the trochlea of the femur is very high, the external, on the other hand, being only slightly developed. The patella itself is smaller than that of the horse, and possesses a small cartilaginous prolongation, principally on its inner face, in marked contrast with the large cartilage found in the horse. As in the latter animal, the outward displacement of the patella is only prevented by the internal patellar ligament and the femoro-patellar aponeurosis. Under the influence of varying causes to which the joint is exposed, these supporting structures often prove insufficient to prevent the patella being displaced outwardly. =Causation.= From an anatomical standpoint, luxation inwards seems impossible. It certainly must be very rare and be preceded by rupture of the external ligament. On the other hand, as in the horse, it seems possible that the patella may be caught on the summit of the internal lip of the trochlea, especially if the trochlea happens to present a flattening at that point.