CHAPTER VI. THE THEORY OF SEXUAL INVERSION. What is Sexual Inversion ?--Causes of Diverging Views--The Theory of Suggestion Unworkable--Importance of the Congenital Element in Inversion--The Freudian Theory--Embryonic Hermaphroditism as a Key to Inversion--Inversion as a Variation or "Sport"-- Comparison with Color-blindness, Color-hearing, and Similar Abnormalities--What is an Abnormality ?--Not Necessarily a Disease--Relation of Inversion to Degeneration--Exciting Causes of Inversion--Not Operative in the Absence of Predisposition..