Few observations have been made on the histological changes associated with slipped femoral epiphysis. Those that are available are confusing, if not actually misleading, in that they have been made on material removed at operation some considerable time after the event, and thus show only the late stages of repair (Lacroix and Verbrugge 1951, Sutro 1935). SO far as we are aware no observations are available on the early stages of the disease, particularly the prodromal change which allows the displacement to occur. Since opportunities to secure such material clinically are rare indeed, recourse to experimental methods is desirable. A method has been devised for detaching the upper femoral epiphysis in growing rabbits. While it is admitted that this technique does not parallel the common clinical situation of insidious displacement, it does allow study of the early phases of repair after acute displacement, and is of special value in assessing the various surgical procedures used in treatment of this condition.