1. Twenty-two dislocations of the hip occurring in patients paralysed from an early age have been studied. All showed abnormal coxa valga. The coxa valga, which may gradually reach 180 degrees, precedes dislocation and makes it inevitable. The presence of unbalanced adductor power may hasten dislocation, but the latter can occur in complete flaccid paralysis.

2. The combination of structural instability of the hip joint and muscular weakness may make independent walking impossible, but restoration of stability gives considerable improvement in any remaining muscular power and may alter the patient's whole future.

3. A method of correcting the basic deformity of coxa valga by osteotomy is described and the results of nine operations are reviewed.

1. The examination of fifty-one infants presenting signs of unilateral dysplasia (preluxation) of the hip disclosed the existence of an abduction-contracture in the opposite "normal" hip.

2. The abduction-contracture was not infrequently found in the newborn, but seemed to attract attention mostly between the second and fifth month of life. It was seldom found after the sixth month.

3. The dysplasia in the contralateral hip showed the usual features.

4. The relationship between the degree of abduction-contracture and the degree of dysplasia was a direct one only occasionally; in most cases they seemed unrelated to each other.

5. Observation of these patients showed that the abduction-contracture followed a constant course towards gradual and spontaneous regression. The dysplasia progressed in one of the following directions: spontaneous recovery, rapid or slow recovery with treatment by abduction splint, subluxation, or true dislocation.

6. It is submitted that the coexistence of unilateral dysplasia of the hip and abduction-contracture in the opposite hip is not fortuitous. It is believed that the abduction-contracture determines the development of the dysplasia in the opposite hip through the faulty mechanics caused by "fixed pelvic obliquity."

7. The discovery of unilateral abduction-contracture soon after birth should be a warning that dysplasia may develop in the opposite hip. A careful watch should therefore be kept for signs of abduction-contracture and for the later development of dysplasia.

1. Injuries to the atlas and axis may occur at any age. They are usually not fatal.

2. In children spontaneous rotatory dislocation is the commonest type of lesion. In adults fracture of the odontoid process is more likely.

3. The spinal cord is often undamaged. In some cases complicated by cord damage the neurological disturbance is caused by an associated injury to the lower cervical spine.

4. Spinal cord damage may be immediate or delayed.

5. In cases of incomplete cord lesion there may be recovery of function after reduction of the displacement or without such reduction.

6. Diagnosis rests on the history and physical signs, and radiographic findings. Radiographs of this area require careful interpretation, and special radiographic techniques may he necessary. A normal radiograph does not necessarily exclude the possibility of atlanto-axial injury.

7. Though many patients would survive without treatment the initial discomfort and danger of complications demand that adequate protection be provided. In relatively minor injuries and in old people protection by a plaster collar may be sufficient. In some cases it is justifiable to undertake manipulation and apply a plaster. Cases with severe displacement require traction, preferably by skull calipers. Recurrent displacement, instability, and cord signs demand operative reduction and fusion. Satisfactory fusion of the atlas and axis alone is feasible, and good function is preserved. More extensive fusion of the cervical spine is seldom necessary.

1. Sixty-five cases of medial fracture of the femoral neck treated by substitution of the head by an acrylic prosthesis have been studied.

2. In general, the long-term clinical results of prosthetic arthroplasty after fresh fractures have been disappointing. The method has given slightly better results in the treatment of old fractures.

3. In view of the almost perfect results obtained after successful Smith-Petersen nailing in the presence of an adequate blood supply to the femoral head, it seems unjustifiable to abandon this principle for immediate substitution with an acrylic femoral head. Nevertheless it is believed that an arthroplasty of this type is justified in fractures seen late, and in fresh subcapital fractures when the fracture is irreducible. If a prosthesis is to be used, more protection for the stump of the neck against the strain of weight bearing is essential; a simple head prosthesis is inadequate, and a head with either a neck extension or an intramedullary prolongation may give better results.

Two cases of benign osteoblastic tumours of the spine, occurring in young patients, and presenting as expanding osteolytic lesions with some central calcification and ossification, are described. It is suggested that they represent a condition allied to, but usefully separated from, osteoid osteoma of bone. The name osteogenic fibroma of bone, proposed by Lichtenstein for this type of case, is accepted.

A bone abscess in the distal femoral metaphysis of an eighteen years old girl is described which was found to have been caused by bacterium coli sensitive to chloromycetin only. Surgical treatment combined with local administration of chloromycetin promptly cured the lesion.

1. A metabolic study in a case of myositis ossificans progressiva is reported.

2. The serum showed an increased power of calcification of rachitic rat cartilage.

3. Estimations of alkaline phosphatase showed slightly raised values.

4. Surgical removal of a bony bar was followed by prolonged administration of ACTH and cortisone, but no effect on the calcium-phosphorus balance or on the re-ossification within the area of operation was observed.

1. The range of variation in the movements at the metatarso-phalangeal and interphalangeal joints of the big toe in fifty males has been investigated by means of lateral radiographs.

2. In the "neutral" position the proximal phalanx is dorsiflexed on the metatarsal and the distal phalanx dorsiflexed on the proximal. Sometimes the distal phalanx is plantar flexed on the proximal but this is not associated with any obvious abnormality of function.

3. There is a wide variation between individuals in the amount of movement found at these joints.

4. At the metatarso-phalangeal joint dorsiflexion is much more free than plantar flexion. The opposite is the case at the interphalangeal joint.

5. There is no significant difference between the right and left sides. Only in plantar flexion at both joints are there significant reductions in the range of movement in older age groups. These reductions are not functionally important.

6. There is an inverse relationship between active and passive dorsiflexion: the greater the range of active dorsiflexion, the less is the range of additional passive dorsiflexion.

7. In lateral radiographs the head of the metatarsal is always rounded.

1. A pathological study has been made of eight femurs containing acrylic Judet type prostheses, in patients who had died two to thirteen weeks after arthroplasty.

2. Haemorrhage occurs into the tunnel and into a limited zone of the spongy bone around the tunnel. Organisation of the blood clot is evident at two weeks and new bone formation appears shortly afterwards. At eight weeks the tunnel is lined by a fibrous membrane. Further fibrosis and new bone growth tend to establish a new surface, healing the wound in the bone and sequestrating the foreign body.

3. There is no evidence that the intact methyl-methacrylate appliance had exerted any toxic action on the tissues.

1. Paralysis caused by anterior nerve root section, or by peripheral nerve section, leads to marked changes in the bones and muscles of the affected limb in experimental animals. Vascular changes are not the cause of the bone atrophy in a paralysed limb.

2. The altered properties of the bones of a paralysed limb are due almost entirely to a loss in the quantity of bone; bone quality is only slightly altered.

3. The bone changes that follow paralysis are due to the secondary loss of muscular activity. No evidence could be obtained that nerves exert any specific, trophic influence on bone.

1. Histochemical studies have been made of the distribution of alkaline phosphatase, glycogen and acid mucopolysaccharides in normal growing bones (mice, rats and men) and also in forty cases of pathological bone processes (neoplastic and dystrophic).

2. The study of normal material confirmed that alkaline phosphatase is plentiful in calcification of cartilage and even more plentiful in bone formation (whether enchondral or direct).

3. It was observed that glycogen increased in the cartilage areas about to be calcified, and that it disappeared in those calcified. It seemed that osteoblasts did not always contain glycogen.

4. In the pathological material (tumours and dystrophic processes) there was great phosphatase activity in the osteogenic areas and also in the cartilage about to be calcified. Whereas glycogen was plentiful in some cases of neoplastic or reactive osteogenesis, it was absent from others.

5. In every area of normal or pathological ossification, the presence of phosphatase seems to be a rule; glycogen is often but not always present.

6. It appears that alkaline phosphatase plays an important role in the formation of the protein matrix of bone, but is not associated with the elaboration of the mucoprotein cartilage matrix.

We believe it is premature to draw any definite conclusion on the behaviour and role of the metachromatic substances in the processes of calcification and ossification.

The histochemical study of alkaline phosphatase has shown that this is a valuable method in the detection of reactionary or pathological osteogenic processes which in some cases are difficult to demonstrate with the usual histological methods.