1. Two cases are described in which increased density of the lower femoral epiphysis was due to sarcoma. 2. In one of these, multiple sarcomata were present.
1. Seven new cases of primary reticulo-sarcoma of bone are recorded, including one in which a full necropsy was carried out. 2. The literature of Ewing's tumour and reticulo-sarcoma of bone has been examined and the conclusion reached that the separation of these two tumours is an artificial one. 3. The investigation of our cases confirms this observation.