I. Experimental Immunologic Orchitis.- 1. Antigenicity of Testis.- a) Adjuvants.- b) Antigens of Mature and Immature Testis.- c) Nature of Antigens.- Germinal Cell Antigens.- Nongerminal Cell Antigens.- 2. Antigenicity of Spermatozoa.- a) Nature of Antigens.- b) Histocompatibility Antigens.- 3. Antigenicity of Seminal Plasma.- a) Antigenic Components.- b) Antigenic Potency.- 4. Antigenicity of Male Accessory Glands.- a) Prostate Gland.- b) Seminal Vesicles.- 5. Antibodies.- a) Humoral Antibodies.- Anaphylaxis.- Complement Fixing.- Precipitins.- Hemagglutinins.- Immobilisins.- Cytotoxins.- Agglutinins.- Cytophilic Activity.- Immunofluorescent Antibody.- b) Cellular Immunity.- 6. Histopathology.- a) Light Microscopy.- b) Electron-Microscopy.- 7. Pathogenesis.- a) Morphologic Basis.- b) Role of Humoral Antibodies.- c) Role of Cellular Immunity.- d) Requirement for Both Antibodies.- e) Role of Sertoli Cells.- f) Relation to Homograft Rejection.- g) Sensitization in the Absence of Adjuvants.- Effect of Unilateral Thermal Orchitis on the Contralateral Gonad.- Homologous Sensitization with Thermal Orchitis Homogenate.- Autologous Sensitization with Thermal Orchitis Homogenate.- Effect of Unilateral Traumatic Orchitis on the Contralateral Gonad.- 8. Prevention of Immunologic Orchitis.- a) Tolerance.- Neonatal Sensitization.- Postnatal Sensitization.- b) Passive Transference of Homologous Serum.- c) Thymectomy.- d) Antimetabolites.- II. Clinical Immunologic Orchitis.- 1. Antigenicity of Human Testis.- a) Induced Allergic Orchitis.- 2. Antigenicity of Human Spermatozoa.- a) Immobilization Test.- b) Agglutination Test.- c) Cytotoxicity Test.- d) Nature of Antigens.- Coating Antigens.- Soluble and Insoluble Antigens.- e) Immunohistochemical Localization of Antigens.- Peroxidase Labeling.- Fluorescent Labeling.- f) Blood Group Isoantigens.- g) Histocompatibility Antigens.- 3. Antigenicity of Human Seminal Plasma.- a) Antigenic Components.- b) Nature of Antigens.- c) Origin of Antigens.- d) Cellular Immunity.- 4. Antigenicity of Male Accessory Glands.- III. Antisperm Antibodies in Male Infertility.- 1. Clinical Findings.- a) Spermagglutinating Antibodies.- b) Sperm Immobilizing Antibodies.- c) Cytotoxic Antibodies.- d) Immunofluorescent Antibodies.- e) Other Humoral Antibodies.- 2. Immunologic Pathogenesis.- a) Pathologic Findings.- b) Mechanism of Autosensitization.- Conclusions.- Acknowledgements.- References.