THE HI-MAX CELLS OF SERTOLI. 



cell (A) pushing out before it an old and degenerate one (D). 



A Sertoli cell i- therefore produced to every twenty-four -perma- 

 tid-, and alter the latter have metamorphosed into spermatozoa 

 and the-.- spermatozoa have become discharged from the tubule-. 

 that Sertoli cell de-enerates. Formation of Sertoli cells must 

 then continue through life as \\\- as formation of germ cell- 

 continues. 



\Ve now pa-- u the hi-tory of tin- rod in the Sertoli cells, that 

 n markable body which differentiate- them from the functional 

 uerm cell-. Tin- i- at lir-i a -imple md. and may remain such 

 n in the bcjinniii'j enlargement of the- cell Fig. 25, 1'!. II.). 

 I)iil tin- rod di\ide-. and in in before the ^ertoli cell 



IDS it- Drouth. - ; it- divi-ion are rarely found, and 



tin- only on.-- oli-erved are illustrated in FU-. ?<> JO, I'l. III. 

 It \\ill l>e -eeii that in the case- of I'u-. jo j^ ;lu- rod i- under- 

 [ual longitudinal cleavage, a more -lender and -hortcr 

 rod .tb-lriciinv, from a portion of tin- larg< r on< ; this -mailer rod 

 may lie < ailed the primary rodlet. 1'erhap- one rea-oii \\liy 

 tli are SO M-ldom found i- lu-cau-e tin- di\i-ioii tan 1 ie 



i i learly only \\ hen the rod lie> at a jiarticular an^le of \ i-ion. 

 \\ 'helher I imply an nmiMiallv ln-nt rod, or one 



that i- in process of di\i-ioii. i- hard to determine, for it \\ a- 

 an i-ol.iied ca-e. The condition immediately follo\\ inu thi- di\ i- 

 >ioii i- -lio\\n in Fig. 31, \\ith an uniisiialK Ion- piiniar\ rodl.-t 

 (r. 1 1 i -01 1 1 pie 1 1 -I \- separated from the rod R.) ; this is a cell body 

 of the \oliuiie of that of an antepenultimate spermatogonium, 

 \\heie .n i "i<lini;l\- cytOplasmic di\i-ion h.id not otcurred, and 

 \\here the original inn leu- had di\ided \\hile onl\ one of it- 

 daughter nuclei had di\ided a^ain. .\ of rod and primarx' 



rod let together at an unu-ually lat' i- n-pre-ented in I 



P. ri. iv. 



In four fifth- of tii -, in M out of KJO cell- examined, the 



large rod conipleteK- di-appear- before tin- Serti>li cell Starts in 

 it- -routh and in -uch ca-e- only the primarx r..dlci i- to I n: 

 seen I igS. \2 J3, I'l. III. . Ju-t SO soon a- tin- cell enla: 

 a ]>aii- o| secondary rodlet- are seen in-lead of the primar\- 

 rodlet I ig. ; } . and uithout dotilit the-.- are produced by equal 

 longitudinal cleavage ol tin- primary rodlet. for they are alway- of 



