Some Observations on Mouse Spermatids

Abstract

Mammalian spermatogenesis has recently been reviewed by Gresson (1951). He emphasized that there is no general agreement as to the nature of the mitochondrial sheath of the middle-piece. The points at issue seem to be whether it is spiral in structure and whether it is granular or a continuous band. Gresson (1950) claimed the sheath is a spiral, workers with the electron microscope (Randall and Friedlaender, 1950; Bretschneider and van Iterson, 1947; Bretschneider, 1949) claimed a spiral structure. This work has been done mainly on mature sperms. Gatenby and Woodger (1921) and Gatenby and Beams (1935) did not support the spiral structure, but gave evidence for the existence of separate granules in the spermatid middle-piece. Benda quoted in Wilson (1925) gave figures showing a granular and spiral structure, though the figures are not clear. While the present paper was being prepared, Austin and Sapsford (1952) published phase-contrast photomicrographs of surviving rat spermatids, and said that the mitochondria form a spiral structure developing from a granular to a continuous spiral. At the present time attention is centred on the cytochemical structure and physiological function of the middle-piece (Rothschild and Cleland, 1952). As a preliminary to cytochemical work, it seemed important to demonstrate the morphology in a convincing way, by using carefully chosen techniques of fixation especially suitable for cytochemistry (Bell, 1952; Gersh, 1952).