Abstract
Histopathology typical of allergic orchitis developed in testes of inbred guinea pigs 16 months after vasoligation. A similar histopathology was found in unoperated testes after unilateral vasoligation. Peritoneal exudate cells from vasoligated guinea pigs transferred identical lesions to syngeneic recipients. The testicular lesions in long-term vasoligated guinea pigs have an immunological basis.