SUMMARY

The production of androgenic hormone (as judged by the weight of the accessory sex organs) was not diminished in the course of 25 weeks following exposure of the testes of rats to 5000 and 10,000 r of X-rays. The characteristic changes in the weights of the pituitary and adrenal glands which usually follow castration were not observed in the X-ray sterilized animals. The seminiferous epithelium was completely destroyed and did not regenerate during the post-operative period ofobservation of 25 weeks. Most of the intertubular cells remained histologically normal after irradiation. The proportion of intertubular to tubular tissue was considerably higher in the irradiated than in the non-irradiated animals. X-ray sterilized animals, like their non-sterilized litter-mates, responded to the administration of gonadotrophin by an increased production of androgen. Copulatory activity was not influenced by X-ray sterilization. All matings except one were sterile. Females inseminated by irradiated males became pseudopregnant (as judged by vaginal smears). X-irradiation of the testes of laboratory animals with doses sufficient to cause depletion and/or destruction of the germinal elements is not followed by atrophy of the accessory sex organs, or by cessation of copulatory activity [Bourg, 1931