White swelling is to be differentiated from peri-synovial gummata, from myeloma and sarcoma of the lower end of the femur, and from bleeder's knee. In the first of these the swelling is nodular and less uniform, and there may be tertiary ulcers or depressed scars in the neighbourhood of the patella. In tumours the swelling is more marked on one side of the joint, it is uneven or nodular, it does not correspond to the shape of the synovial membrane, and may extend beyond the limits of the joint, and it involves the bone to a greater extent than is usual in disease of the joint. Skiagrams show expansion of the bone in central tumours, or abundant new bone in ossifying sarcoma. The diagnosis of bleeder's knee is to be made from the history. (5) _Primary Tuberculous Disease in the Bones of the Knee._--So long as the foci are confined to the interior of the bone, it is impossible to recognise their existence, unless they are of sufficient size to cause enlargement of the bone or to be discernible in a skiagram. #The formation of peri-articular abscess# takes place in rather more than fifty per cent. of cases. When left to themselves, such abscesses tend to spread up the thigh, or down the back of the leg between the superficial and deep layers of calf muscles, and numerous sinuses may result from their rupture through the skin. #Attitudes of the Limb in Knee-Joint Disease.#--The attitude most often assumed is that of _flexion_, with or without _eversion of the leg and foot_. The flexion is explained by its being the resting attitude of the joint, and that which affords most ease and comfort to the patient. Once the joint is flexed, the involuntary contraction of the flexor muscles maintains the attitude, and if the patient is able to use the limb in walking, the weight of the body is a powerful factor in increasing it. The eversion of the leg is probably associated with contraction of the biceps muscle. _Backward displacement of the tibia_ is met with chiefly in neglected cases of chronic disease of the knee when the child has walked on the limb after it has become flexed. In certain cases, _genu valgum_ or abduction of the leg is present along with a slight degree of flexion. The valgus attitude is associated with slight lateral displacement of the patella, with prominence and apparent enlargement of the medial condyle, with depression of the pelvis on the diseased side and apparent lengthening of the limb. #Treatment of Tuberculous Disease of the Knee.#--Conservative measures are always indicated in the first instance, and are persevered with so long as there is a prospect of obtaining a movable joint.