An analysand somnambulistically lit a bedside lamp during the night following an anxiety-producing episode of rivalry with a father-figure. This rivalry revolved about the fear that the father-figure would suspect the patient of having intercourse with his (patient's ) wife, who represented for him his mother. The somnambulistic act served a double purpose: it allayed the fear of paternal attack in the dark, at the same time permitting the feared father to see that the patient was sleeping alone and not with the mother.