THE dead body of Marie Visneffska lay in the tiny salon of her little villa in the county town of Novominsk, not far from Warsaw. It lay beneath the one large picture in the room, a portrait in a gilded frame of her once beautiful niece, whose success as a leading lady had not been entirely due to her activities behind the footlights. An officer of a Hussar regiment, surprising her one day with a rival, shot her, undressed his victim, and left the body strewn with cherry-blossom.