1. The normal vascular anatomy of flexor tendons and extensor tendons in the hind limb of the rabbit is outlined. A marked difference between a tendon in a sheath and a tendon with a paratenon is shown, the latter having a much better blood supply.

2. The vascular reaction in flexor tendon divided within a sheath is shown.

3. The revascularisation of free grafts is illustrated and the differences between tendon with sheath and tendon with paratenon are detailed.

4. Experiments are reported to show that the microcirculation within a "vascular" tendon can support a pedicle graft in the rabbit. Such pedicle grafts are shown to be inferior to free grafts of "avascular" tendon, but the vascularity within the pedicle tendon graft may be modified by "blocking" the surface with silastic tubing.

5. The implications of this work on tendon grafting are discussed, together with a review of additional experimental work in related fields.

1. Two cases of pseudomalignant osseous tumour of soft tissue are reported and added to the nineteen cases in the literature.

2. The clinical and histological features are described and distinguished from myositis ossificans, osteogenic sarcoma in soft tissue and parosteal fasciitis.

3. In one case the non-malignant nature of the lesion has been confirmed by its spontaneous regression.

1. Fifty knees affected by rheumatoid arthritis were studied in detail at synovectomy.

2. The destructive lesions found were relatively constant and are described in detail.

3. Cartilage lesions were much more common than was expected radiologically.

4. The pattern described suggests that articular cartilage is destroyed by contact with diseased synovial membrane but protected by contact with another cartilaginous surface.