Abstract
Spermatogenic arrest in man was studied by transillumination, phase contrast microscopy, and conventional histology. The spermatogenic arrest occurred at the late pachytene stage, and the degeneration of the germ cells could be studied more accurately with phase contrast microscopy of living cells than with conventional histology. The Sertoli cells rapidly phago-cytosed the degenerating cells, which could be seen on transillumination as dark spots along the whole length of the tubule.