=II. Development of the Love-Life=—Stages of Sexual Development—Friendship and Love—Esthetic Significance of Sex— Love the Refinement of Sexual Impulse—Altruism and Self-Sacrifice—Sex Life of the Child—Sexual Instincts Manifested from Birth—Stages of Progress—The Detumescence Instinct—The Autoerotic Stage—Sucking, an Erotic Pleasure— Erogenous (Love-producing) Zones—Narcissism—The Legend of Narcissus—Self-love—Prepubescence—Love in Childhood— Childhood’s Sex Interests Repressed—Sublimation—Erotic Compensation—Cultural Accomplishments—Adolescence—The Boy and Girl—Physical and Psychic Manifestations—What Impels to Love— The Parent Image—Copying Psychological Patterns—Ego and Sex Ideals—The Love-Object—Fixations—Peculiarities of the Love-Life—Psychic Impotence—Frigid Wives—Fetichism—Sexual Significance of Fetiches—Exhibitionism—Normal and Abnormal Traits—Sexual Curiosity—Sadism and Masochism—Homosexuality— Psychological Problems—Environmental Factors—Homosexual Feelings Repressed. =III. Man’s Sexual Nature=—Comparison of the Male and Female— Represent Different Types of Eroticism—Anatomy and Physiology of Male Sex Organs—The Penis—The Glands—The Prepuce— Circumcision—The Testes—The Vas Deferens—The Epididymis—The Seminal Vesicles—Cowper’s Glands—Prostate Gland—Urethra—The Seminal Fluid—Semen—Spermatozoa—Internal Chemistry—Ductless Glands—The Hormones—Interstitial Glands—Chemical Aspects of Sex—The Endocrine System—Thyroid—Parathyroid—Pituitary— Adrenals—Thymus—Pineal—Pancreas—Insulin—Activity of Male Sex Organs—Nocturnal (night) Emissions—A Normal Episode—Diurnal (day) Emissions—Man’s “Change of Life”—A Preparation for Senescence—Period of Sexual Decline—The Don Juan—A Constructive Period Ahead. =IV. Woman’s Sexual Nature=—Sexual Instinct in Woman—Woman’s Sexual Organization More Complex Than Man’s—Feminine Eroticism More Highly Ramified—Woman’s Emotional Nature—Strength of Sexual Impulse—Woman Sexually Conservative—Variations in Sexual Impulse—Sexual Desire Outlasts the Reproductive Life— Anatomy and Physiology of Female Organs—The Ovaries—Graafian Follicles—Process of Ovulation—Fallopian Tubes—Salpingitis—The Uterus (Womb)—The Vagina—The Hymen—The Vulva—Bartholin Glands— The Pelvis—The Mammary Glands—The Internal Secretions—Normal Effects at Puberty—Effects of Deficiency of Secretions— Menstruation—Symptoms of Initial Appearance—Hygiene of Menstruation—Disorders Due to Constipation—Re-establishing Premature Cessation of Flow—The Menopause.