442 HOMER WHEELON 



of the testes are revealed by the studies of the selective action of the x-rays, 

 vasectomy, and undescended testes, i. e., cryptorchism. 



Effects of the X-rays on the Testis. The studies of Albers-Schonberg, 

 Bergoine and Tribondeau, Regaud and Dubreuil (a) (c), Gordan and 

 Simmonds (a) have clearly shown that the x-rays exert deleterious effects 

 upon the male genital glands. Male rabbits and guinea pigs exposed to the 

 action of these rays and later given ample opportunity to copulate with un- 

 exposed females fail to impregnate them. However, such males demon- 

 strate normal desires and potency. Microscopic examination of the testes 

 of such males shows a reduction or absence of spermatogenesis. Many 

 observers have recorded the absence or the infrequency of spermatozoa in 

 the semen of men following exposures of various degrees to the x-rays. 

 Such individuals do not develop marks of impotence or loss of sexual in- 

 stincts (Brown). Furthermore, the exposure of males possessing well 

 marked secondary sexual characters to the influence of the rontgen rays in 

 no wise alters such characteristics. On the ether hand irradiation of the 

 whole body of white rats, according to Hewer (&), when the animals are 

 very young does hasten sexual development in the male. 



Histological studies have clearly shown that the x-rays, while destroy- 

 ing the germ cells, fail to alter the interstitial cells. However, Simmonds 

 has shown that even after prolonged exposure, isolated seminiferous 

 tubules remain intact, and, if the animal lives a sufficient length of time, 

 regeneration of the germ cells occurs and spermatogenesis is restored. 

 Furthermore, destruction of the sperm producing cells is invariably accom- 

 panied by proliferation of the interstitial cells, which condition disappears 

 after regeneration of the spermatic cells. The sustentacular cells remain 

 unaffected following radiation. Such observations as these clearly show 

 that the production of sperm is not essential to the integrity of the 

 secondary sexual characters and the sexual instincts. 



Effects of Yaseetomy en the Testis and Sex Characters. Ligation 

 of the vas deferens in immature animals does not inhibit the beginning 

 of subsequent spermatogenesis. The results of such operations, according 

 to Griffiths, are seen as secondary consequences at puberty, when the 

 formation of semen normally occurs, Vasectomy, either unilateral or 

 double, does not inhibit the growth of the prostate or other sex characters, 

 but unilateral vasectomy will prevent the full development of the testis 

 on the side of the operation, as compared in size with the organ on the 

 unoperated side (Marshall). According to Bouin and Ancel (c), Griffiths, 

 Myers, Wheelon, and Kuntz ligation of the vas results in the cessation of 

 spermatogenesis ; spermatocytes and spermatogonia degenerate, and after 

 some months all spermatogenic elements disappear. At first there is no 

 apparent change in the appearance of the sustentacular cells Sertoli cells 

 of the seminiferous tubules; but these, too, ultimately disappear (Tour- 

 nade). On the contrary, the interstitial cells retain their morphological 



