nioii tally 1 



liferent kinds of cells; 1. Thi 



* sper, 



The sperm-i 



nursing cell. The latter have 





v. Ebner, 



in honor of the discoverer: 

 ists (v. Ebner) ; copulation eel 



Is; su 



zellen, Stutzellen ; cellules de seniien, etc. 





The sper, 



m-producing cell is essentially 



migrn 



soon as it attains a certain stage of irr<>wt 



li it 1. 



tubule and 



undergoes a manifold series of 



cluing 



In this r< 







trust to the 



young egg cell, which leads a 



sedelit 



stage of mi 



iturity when it first becomes 





follicle. 







The chai 



iges which the young sperm 



ixt-woi 



leaving the 



: basement-membrane of the ti 



ibnle 



stood. On 



the other hand, the history 



of th 



-utfieiemly 



known. The Sertoli's cell 



lias 



ana is very easy to recognize ov us uimu =..«, 



plasm, by its large vesicular nucleus, and by its eharactc nstie nucleolus. 

 It is not likely that a single set of Sertoli's cells perform the mining 

 function for 'the several consecutive crops of spermatozoa. My 

 conclusion, in regard to this point, as based on the study of human 

 spermatogenesis, may be briefly stated as follows:— The sperm-mn>im: 

 cell (the Sertoli's cell) in the seminiferous tubules of a mammal arises 

 from a distinct anlage of its own, as the spermatozoan arises from the 

 spermatogonium. In short, not only the two kinds of functional mis, 

 -the sperm and its nurse-exist in the seminiferous tubule, but also 

 the distinct antecedent cells for each of them; or more pmp,r.y. u,- 

 existence of two different kinds of cells in the functional seminiferous 

 tubule is due to the existence of two entirely different kinds of ante- 

 cedent cells. Just as the spermatogonia or the "8tanui 

 the antecedent structure for the spermatozoa, bo th B 

 cells— cellules etoih'es of Ren son— found in the 

 the spermatogonia are the antecedents of Sertoli' 

 cell stains quite ditlerently from the adult Sertoli's cell, as the young 

 spermatogonium stains differently from the adult spermatozoan I 

 have been able, however, to trace the series from th. young stellate 

 ceU up to Sertoli's cell almost as completely as between the .ju-rm.t..- 

 gonium and the spermatozoan. The youngest Bpermatogou 

 quite differently from the youngest stellate cell, so that the difference 

 between the two cells, the sperm and its nurse. 

 If they were derived from the same source, the differentiation in these 



