482 



THE REPRODUCTIVE SYSTEM 



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

 phosis, hence also known as 'trophocytes.' 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. SEBTOLI CELLS OF THE HUMAN TESTIS. 



A t 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 spermatoblast 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 investigator's 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- 



