HISTOLOGICAL CHANGES AFTER IRRADIATION • 1115 





Fig. 17-5. (A)-(D) Sections of rat testes after whole-body irradiation with 600 r of 

 200-kv X rays. {A) 21 days; the tubule contains Sertoli cells and groups of spermia; 

 all spermatogenic cells are absent; 350 X. (B) 31 days; the tubule is further collapsed 

 and contains only Sertoli cells; 350 X . (C) 70 days, beginning regeneration of sperma- 

 togenesis. Note the almost continuous layer of dark-staining spermatogonia at the 

 periphery of the tubule, the larger spermatocytes, and the clumps of smaller pale- 

 staining spermatids; 350 X. (D) 8 hours after irradiation; showing the intact 

 spermatocytes and three degenerating spermatogonia indicated by the arrows; G75X. 

 (E) Section of rat testis 24 days after rat was given 5 M c, g of Zr 93 -Cb 93 . The tubule 

 is filled with necrotic cells which stain darkly; 260 X. (After Heller, 1948.) 



