III. The Causes of Prostitution:—Prostitution as a Part of the Marriage System—The Complex Causation of Prostitution—The Motives Assigned by Prostitutes—(1) Economic Factor of Prostitution—Poverty Seldom the Chief Motive for Prostitution—But Economic Pressure Exerts a Real Influence—The Large Proportion of Prostitutes Recruited from Domestic Service—Significance of This Fact—(2) The Biological Factor of Prostitution—The So-called Born-Prostitute—Alleged Identity with the Born-Criminal—The Sexual Instinct in Prostitutes—The Physical and Psychic Characters of Prostitutes—(3) Moral Necessity as a Factor in the Existence of Prostitution—The Moral Advocates of Prostitution—The Moral Attitude of Christianity Towards Prostitution—The Attitude of Protestantism—Recent Advocates of the Moral Necessity of Prostitution—(4) Civilizational Value as a Factor of Prostitution—The Influence of Urban Life—The Craving for Excitement—Why Servant-girls so Often Turn to Prostitution—The Small Part Played by Seduction—Prostitutes Come Largely from the Country—The Appeal of Civilization Attracts Women to Prostitution—The Corresponding Attraction Felt by Men—The Prostitute as Artist and Leader of Fashion—The Charm of Vulgarity. IV. The Present Social Attitude Towards Prostitution:—The Decay of the Brothel—The Tendency to the Humanization of Prostitution—The Monetary Aspects of Prostitution—The Geisha—The Hetaira—The Moral Revolt Against Prostitution—Squalid Vice Based on Luxurious Virtue—The Ordinary Attitude Towards Prostitutes—Its Cruelty Absurd—The Need of Reforming Prostitution—The Need of Reforming Marriage—These Two Needs Closely Correlated—The Dynamic Relationships Involved. CHAPTER VIII.—THE CONQUEST OF THE VENEREAL DISEASES. The Significance of the Venereal Diseases—The History of Syphilis—The Problem of Its Origin—The Social Gravity of Syphilis—The Social Dangers of Gonorrhœa—The Modern Change in the Methods of Combating Venereal Diseases—Causes of the Decay of the System of Police Regulation—Necessity of Facing the Facts—The Innocent Victims of Venereal Diseases—Diseases Not Crimes—The Principle of Notification—The Scandinavian System—Gratuitous Treatment—Punishment For Transmitting Venereal Diseases—Sexual Education in Relation to Venereal Diseases—Lectures, Etc.—Discussion in Novels and on the Stage—The "Disgusting" Not the "Immoral".