A brief review of the literature on malignant change occurring in fibrous dysplasia is given and a further case of a sarcoma arising in a patient with polyostotic fibrous dysplasia is reported.

1. Forty-eight patients with spontaneous rupture of the tendon of the extensor pollicis longus have been studied and the results of forty-four operations by tendon transfer are reported.

2. The etiology and the pathology of the condition are discussed.

3. Transfer of the extensor indicis in general gives a better result than transfer of the extensor carpi radialis longus, but each method has its advantages and disadvantages.

4. The best results are obtained when the suture is done so as to leave the tendon in the fullest degree of tension obtainable.