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 These Two Needs Closely Correlated--The Dynamic Relationships Involved. _I. The Orgy_. Traditional morality, religion, and established convention combine to promote not only the extreme of rigid abstinence but also that of reckless license. They preach and idealize the one extreme; they drive those who cannot accept it to adopt the opposite extreme. In the great ages of religion it even happens that the severity of the rule of abstinence is more or less deliberately tempered by the permission for occasional outbursts of license. We thus have the orgy, which flourished in mediæval days and is, indeed, in its largest sense, a universal manifestation, having a function to fulfil in every orderly and laborious civilization, built up on natural energies that are bound by more or less inevitable restraints.