Employing the concepts of psychic controlling values, body-ego and body schema, a reformulation of the process of conversion is undertaken and illustrated with brief case histories. Voluntary movement is the prototype of psychic control. The body-ego has mobility and agility at its disposal—psychic vectors which determine the movement of the anatomical limbs. The experience of phantom limbs and conversion symptoms demonstrates the non-identity of body-ego and body schema. Conversion is characterized by the displacement of the ego boundary in the sense that parts of the movable