482 



THE REPRODUCTIVE SYSTEM 



draw nourishment from the sustentacular cells for the work of metamor- 

 phosis, hence also known as 'tropkocytes/ The sustentacular cell is 

 roughly of tall columnar shape, tapering somewhat irregularly toward 

 the distal pole. The proximal pole contains the nucleus and frequently 

 flares somewhat giving the entire cell a tall pyramidal shape. The 

 nucleus is pale and contains one or several chromatic nucleoli. The 

 spermatozoa are embedded head first, four to eight or more to a cell, 

 in the protoplasm of the trophocyte. Such a composite group consti- 



. 



: 



FIG. 427. SERTOLI CELLS OF THE HUMAN TESTIS. 



A, showing a crystalloid (of Charcot) and lipoid granules and spherules; below 

 to the right a spermatogonium with a crystalloid (of Lubarsch). B shows a crys- 

 talloid and two accessory rods, and lipoid granules and droplets. C shows at the 

 base a crystalloid and one accessory rod, and at the summit two accessory rods. 

 X 600. (Winiwarter.) 



tutes a so-called spermatollast of von Ebner. The sustentacular cell 

 contains one or several crystalloids. Their origin and function is un- 

 known. They were regarded by Montgomery as probably sustentacular 

 cell determinants, having been traced by him from the common mother- 

 cells of both trophocyte and spermatogonium into the former, the latter 

 being said to lack these elements. However, Winiwarter (Fig. 427) re- 

 ports similar crystalloids in both trophocytes and spermatogonia. Tro- 

 phocytes more probably have an origin distinct from that of the 

 germ-cells, according to certain investigators arising from the Bowman^s 

 capsule of the Wolffian tubules of the mesonephros. 



Every section of a tubule of an active testis contains several, some* 

 times all the stages of spermatogenesis. Since the spermatogenetic 

 process generally travels in waves, a longitudinal section is most favor- 



