1. The epiphyses of the metatarsal heads of 250-gramme rabbits were separated at the zone of cell columns, stripped of perichondrium, labelled with tritiated thymidine and transplanted into the back muscles of the same animals.

2. Endochondral ossification started in the grafts at four days, was well established by seven days and progressed until fourteen days, the end of the study.

3. Progressive passage of the label down the zone of cell columns and into the hypertrophic zone was observed.

4. The tritiated-³H thymidine label had disappeared from the cartilage cells by ten days. No labelling was observed in the bone cells at any stage.

5. It was not possible to demonstrate from the experiment that growth plate chondrocytes are precursors of osteoblasts in the process of endochondral ossification in rabbits.

1. Three cases of traumatic anuria following muscle ischaemia ("crush syndrome") are reported.

2. The pathogenesis and treatment of the condition are discussed.

3. A scheme of management directed to the prevention of renal failure is proposed.

1. Seventy patients with impacted fractures of the femoral neck treated from 1953 to 1965 have been reviewed. Forty-seven were treated conservatively and twenty-three by primary internal fixation.

2. The complications of both methods of treatment are recorded.

3. The prognosis following impacted femoral neck fractures is good. Seventy-nine per cent treated conservatively and 96 per cent treated by primary internal fixation had excellent or good results.

4. Primary internal fixation is the treatment of choice.