1. Nine cases of haemangiopericytoma are described and the treatment is discussed.

2. Six of the patients had a recurrence of the tumour after local excision.

3. Four patients developed metastases and died. All had been treated by surgery and cobalt 60 beam radiation.

4. Five of the patients show no further disease. Of these, two received cobalt 60 beam radiation after surgical treatment.

1 . A case of parosteal osteoma with histologically low-grade sarcomatous areas is described.

2. Arteriography revealed abnormal arteries, the histological appearances of which are described.

3. Vascular shunts indicative of low-grade malignancy were also seen.

4. Reasons are given for accepting the view that this lesion is a tumour, originally benign, but liable to the development of low-grade malignancy.

1 . Criticisms are expressed of previous reports on the use of intra-articular injections in the treatment of osteoarthritis of the knee.

2. A series of 181 patients with primary osteoarthritis of the knee treated by certain intra-articular injections is reported. Three solutions in common use were studied; normal saline and mock injections served as controls.

3. Irrespective of the injection used, including the controls, no significant difference in the effects was demonstrated in the results.

4. The place of intra-articular injection therapy in osteoarthritis is discussed. Attention is drawn to the psychological implications.

1. Three cases of tenosynovitis presenting as the first manifestation of rheumatoid arthritis are described.

2. An account is given of the histology of the affected tendon sheaths.

1. Bones consist essentially of bundles of collagenous fibres united by a cementing substance in which the inorganic material lies in the form of minute plate-like crystals.

2. During weight bearing and muscle action bones as a whole are deformed to a variable extent. Periods of deformation are followed by periods of relaxed pressure during which the bones tend to return to their normal form.

3. These variations in deformation and elastic recoil set up alternating pressures and tensions within the bones along the bone cyrstal encrusted fibres which make up the trabeculae, lamellae and Haversian systems, and these alternating phases of compression and tension stimulate the activity of osteoblasts so that bone formation predominates over bone resorption.

4. These alterations of pressure and tension are intermittent and reciprocal in nature and do not, as postulated by the trajectorial theory, involve different trabeculae, nor is it necessary to consider whether tension or pressure is the more important phase in determining bone deposition.

5. The pressure exerted by cysts, tumours, erupting teeth, etc., is of a quite different nature, as is the response to trauma or callus formation in the healing of fractures. These processes are essentially vascular phenomena involving localised areas of bony tissue and not bones as mechanical units.

1 . The repair of a simple crush injury was studied in rats, in both normally innervated and completely denervated muscle. In each case the histological findings at periods from two hours to thirty-two weeks are described.

2. The denervated muscle showed active and effective repair.

3. A comparison with the findings in normally innervated muscle establishes that the cellular processes of repair do not depend on connections with the central nervous system.

1 . The extraordinary background and circumstances of discovery of a man, aged fifty, the subject of the rare congenital anomaly of posterior dichotomy, taking the form of a hemipelvis and complete lower limb is reported.

2. The appendage is described and illustrated.

3. Investigations and treatment are described and the result illustrated.

4. Reference is made to previous recorded cases in the literature.

1. The posterior Monteggia fracture usually conforms to a typical pattern.

2. Its incidence is greatest among middle-aged women.

3. The mechanism of the injury is probably similar to that of the dislocated elbow. Excessive rotation of the forearm plays no part in its production.

4. Internal fixation of the ulna combined with excision of the whole radial head, or of its detached segment, is suggested as the treatment of choice.

5. The functional results after operation are excellent, but some slight permanent restriction of movement is to be expected.

1. Pain and pressure sensibility has been studied in the fibrous articular ligament and synovial membrane of the knee joint in normal human subjects and in patients subjected to arthrotomy under local anaesthesia.

2. The fibrous ligament was found to be a highly sensitive structure, containing many spots which give rise to sensations of pain or pressure when stimulated mechanically or chemically. Synovial membrane was found to be a relatively insensitive structure which only occasionally contains pain-sensitive spots.

3. Histological examination of articular capsule from the knee joints of normal and sympathectomised cats shows that articular ligaments have a rich nerve plexus and a variety of specialised and unspecialised nerve endings, most of which are somatic in origin. Synovial membrane contains a more delicate nerve network and also a variety of nerve endings, the majority of which are autonomic in origin. But a substantial number of somatic nerves enter the synovial membrane, some of which terminate in nerve loops, globular endings or simple unspecialised endings.

4. Histological examination of normal human articular capsule shows that its innervation closely resembles that of the cat, but no sympathectomised human material was examined.

5. The bearing of these findings on the symptomatology of joint disease is discussed briefly.