The healer's work in tracing disease is subtler than healing; for in healing power is necessary, but in tracing the disease -- its nature, its cause, its secret -- psychic power is of no use, there inspiration is needed, and a healer without this is an incomplete healer. The patient generally does not know the real cause, nature, and secret of his complaint. He is not supposed to know, for the patient knows the effect of the poison, not its cause, nature, and secret. The healer must trace the patient's complaint from his face, expression, voice, work, and movement; everything tells. Sometimes the healer must find out the cause by asking the patient the details about his pain and the circumstances of his life, and by knowing the attitude and the inclination of the patient.