On the development of general conceptions -- Male and female -- Contradictions -- Transitional forms -- Anatomy and natural endowment -- Uncertainty of anatomy CHAPTER I MALES AND FEMALES 5 Embryonic neutral condition -- Rudiments in the adult -- Degrees of “gonochorism” -- Principle of intermediate forms -- Male and female -- Need for typical conceptions -- Resumé -- Early anticipations CHAPTER II MALE AND FEMALE PLASMAS 11 Position of sexuality -- Steenstrup’s view adopted -- Sexual characters -- Internal secretions -- Idioplasm -- Arrhenoplasm -- Thelyplasm -- Variations -- Proofs from the effects of castration -- Transplantation and transfusion -- Organotherapy -- Individual differences between cells -- Origin of intermediate sexual conditions -- Brain -- Excess of male births -- Determination of sex -- Comparative pathology CHAPTER III THE LAWS OF SEXUAL ATTRACTION 26 Sexual preference -- Probability of these being controlled by a law -- First formula -- First interpretation -- Proofs -- Heterostylism -- Interpretation of heterostylism -- Animal kingdom -- Further laws -- Second formula -- Chemotaxis -- Resemblances and differences -- Goethe, “elective affinities” -- Marriage and free love -- Effects on progeny CHAPTER IV HOMO-SEXUALITY AND PEDERASTY 45 Homo-sexuals as intermediate forms -- Inborn or acquired, healthy or diseased? -- A special instance of the law of attraction -- All men have the rudiments of homo-sexuality -- Friendship and sexuality -- Animals -- Failure of medical treatment -- Homo-sexuality, punishment and ethics -- Distinction between homo-sexuality and pederasty CHAPTER V THE SCIENCE OF CHARACTER AND THE SCIENCE OF FORM 53 Principle of sexually intermediate forms as fundamental principle of the psychology of individuals -- Simultaneity or periodicity? -- Methods of psychological investigation -- Examples -- Individualised education -- Conventionalising -- Parallelism between morphology and characterology -- Physiognomy and the principles of psycho-physics -- Method of the doctrine of variation -- A new way of stating the problem -- Deductive morphology -- Correlation -- Outlook CHAPTER VI EMANCIPATED WOMEN 64 The woman question -- Claim for emancipation and maleness -- Emancipation and homo-sexuality -- Sexual preferences of emancipated women -- Physiognomy of emancipated women -- Other celebrated women -- Femaleness and emancipation -- Practical rules -- Genius essentially male -- Movements of women in historical times -- Periodicity -- Biology and the conception of history -- Outlook of the woman movement -- Its fundamental error