THE IITMAN CELLS OF SERTOLI. 37 T 



of Fig. 17; this shows four nuclei, the granddaughters of the 

 nucleus of an antepenultimate spermatogonium. while there has- 

 been no division of the cell liody. and it will he seen there is 

 but one rod to the four nuclei. The evidence is then decishe 

 that one quarter of the cells for this generation contain each 

 one rod. 1 In these cell- the rods arc on tin- average more- ma--i\ e 

 than in preceding grin-rations (Fig-. 17 24), and while usually 

 iiion- or less curved an- never t\vi-ted. (Juite frei|uently one end 

 of i he rod is bent off at an .ingle Figs. 17. - 1 - 1 . In these cells 

 al-o the rod- an- nio-t den-e ,md acquire their maximum -tain, 

 staining fully as inten-elv as the basichromatin ; they generally 

 hut not aluays touch the nuclear .-urfat v. 



5. DIFFERENTIATION AND HISTORY "i un SERTOLI CELLS 



(Fit.-. j 5 50). 



All thr ultimate SpermatOgonia that contain n>d> hecoine cells 

 of ^i-rioli, and ihosi- only. Nothing like either rod- or rodlets 

 Were found in any of the SDermatOCytes or -permatid- The 

 N-iioli cell- hrconir e-| le. i. il I \- marked h\ their great 



25, I'l. [I., shows the beginning ol -uch ^n>\\ ih, 

 (ell (A) growing out heMmd it- sister uliimate -|iennaio-.uiia 

 I H ,ind ( . I , | and .i-. I'l. N I .. -lm\v ^ertuli cell- in a later 



growth 'agr in their eiitiret\. and 1 19, 41-46 exhihit 



portions of them in still later -i 1 !n se elU hec.mie icl.i- 



ti\i 1\ enormous as shown in I i. I'l. \'., \\liich n-pre-eni- a 



pi-rtii'ii of a transection of tlu- \\all t a -emiuilerou- iiihule; in 

 thi> ligure tlu- shaded portion represents the hmlie^ nf the Sertoli 

 cell-, \\hich have grown far into the lumen of the tuhtile \ 

 emhi.n e i he -per ma lids. Thi- ^icat growth i- due mainl\ to the 

 formation of \'acuoles within the e\i>pl.i-m. and in the li-mv- 



onl\ the larger of the vacuoles are shown, not tin- gn-at numher 



<>1 minut. . These vacuoles are drop- ,,)' a noii laiiiin- 



llu id. like that contaim-d \\ ithin the ca\ it\ of the tuhule; only in 

 rare in-tances are an\ - concretion-, found in the \ at uole>. ( )ne 

 end, the ha-al, of eac'h Sertoli cell remain- adherent to the lihrous 

 \\all of the tuhule and in the figures lim - are draun to denote 



1 Spi-iinat<;:i'iii.i \\ itli two. tlin-c or l<.nr nucli-i in a -ini;!.- o-ll bmly arc- unusually 



In .|in-iu aii'l in >u. 1, Ut l( i an i:.-i[iii-nily \ (jiiitc um-qu.il vili;- 



