1. Two children suffering from Gaucher's disease, who developed changes in the femoral head typical of Perthes' disease, are reported. Similar changes have been recorded in the literature in seventeen children under the age of fifteen years.

2. The possible factors giving rise to the bone changes are discussed and it is considered that they result from aseptic necrosis. Splenectomy does not appear to hasten the development of bone changes in this disease.

3. In one of the patients, the blood Wassermann reaction was positive, but syphilis was not thought to play any part in the production of the bone changes.