1. Cancellous bone grafting of the head of the femur in Perthes' disease accelerates reossification and thus shortens the period of treatment.

2. There is no evidence from this series of cases that the final shape of the head is affected for better or for worse by the operation of cancellous chip grafting, by the rate of regeneration of the head after operation or by the stage in the disease process at which the operation is done.

3. No relationship has been found between the shape of the head at the time of operation and its final shape.

4. A larger series of cases is needed to determine the value of bone grafting in Perthes' disease of the hip.