Material is brought from writings of Baudelaire and of Edgar Allan Poe to shew that the nucleus of the Oedipus complex is the fear and horror aroused by the sight of the menstrual bleeding of the mother. The matricidal urges and the guilt resulting from them unite with fear of castration arising from the Oedipus guilt, when the child is confronted with the sight of the mother's bleeding body, to erect the incest barrier. The descriptions of scenes of blood, taken from both authors, are tellingly and convincingly used to shew the deep significance for the child of its early impressions of menstrual phenomena.