THE HUMAN CELLS OF SERTOLI. 369 



malic rod-. never more than one to a cell, various forms of which 



dra\\n in Figs. 2-8, that of Fig. 5 being the largest found. 



The rods are homogeneous in appearance, dense, and they -tain 



with ha-ir -lain- but u.-ually not as intensely as in the later 



Denial generations. Such rod- are u-ually in contact 



with tin- nuclear -urface, hut not always, and do not occupy 



constant po-iiion- with regard to the pole- of the cell. Inar- 



acteristic of the antepenultimate spcrmatogonia i* 'he relatively 



-in, ill -i/e of >d- and their frequently twi-ted form. 



Thirty of the-e ceil- were carefully examined, and tuvntv- 

 thn-e if them showed each one n,,|. ( )f the remaining -e\ en, 

 fi\e were ii"i \\holl\- within the plane of the section, so that their 

 rod- mav have been present in the < i portion-. It i-, prob- 



able thai each < ell of this g< ]] -rat i>n comes t<> contain a rod, and 

 thai the rod- are first produced in thi- generation; no -perm, 



ia o| e.irlier ^mcrations \\ere pre-ent, houexer. consequently 

 there can I"- no -urety of the latter point. 



What the nietliod of origin of th I- mav lie could not 



In- determine<l. They are quite di-timi from the idio/ome. at 

 least when fully formed, as shown in Fig. 2. In our i 



no rod was found lull an irregular granular mass which i- 



po--ilil\ .1 precursor of the rod; if this be so, the roil mi-hi I.e 



con-ideieil to lie produced l>\ the glomeration of granules 



at lir-! red in the cell body. Hut the -tate of fixation of 



the c\ to|ila-m was not sufficiently reliable to allo\\ of an\ -ali-- 

 factorj d ii i inination of this matter. There i- no e\ idence that 

 the rod- are directly produced from the nucleii-. I heir origin 

 is thus unexplained, though their -ul >-ei iiieiit hi-tor\ i- perfect 1\- 



( leal . 



\o mitoses of these cells were found, but there can be no doubt 



that the rod- do not become divided for ju-t half of the cell- of 

 the next generation contain rod-. 



; v Till I'l \i LTIMATE M'l KM \ \l\ FlGS. -i !< , 



l'ort\ -nine cell- of this generation \\en- examined, care being 

 taken to -tu<l\ only those that lay entirely within the plane of 

 the section, and of the-e tuenty-foiir exhibited each a rod \\hile 

 t\\entv-fi\e -houed no rods. ANo -ix cases \\ere found of tuo 



