130 GERM-CELL CYCLE IN ANIMALS 



claim that they arise from cells other than germ cells ; 

 these writers have been called by Waldeyer (1906) 

 " dualists." An equal number of authorities be- 

 lieve that both Sertoli cells and spermatogonia 



Fig. 41. — Stages in the formation of the Sertoli cell in man. A. Sper- 

 matogonium containing granular inclusion (X) from which " Sertoli 

 cell determinant " vfiay arise. B. Antepenultimate spermatogonium 

 showing rod (i2) and idiozome (/). C. Division of rod. Z). A Ser- 

 toli cell containing a divided rod {R) and two rodlets {j-^. E. Ser- 

 toli cell with crystalloid of Charcot and lipoid granules ; at lower 

 right corner a spermatogonium with crystalloid of Lubarsch. {A-D, 

 from Montgomery, 1911; E, from von Winiwarter, 1912.) 



originate from primordial germ cells ; these are the 

 " monists." 



The researches of Montgomery and von Wini- 

 warter have decided the question, at least so far as 

 man is concerned, in favor of the monists. Mont- 

 gomery's results are diagrammatically shown in 

 Fig. 42. Of thirty antepenultimate spermatogonia 

 examined, twenty-three contained each a rod-shaped 

 structure (Fig. 41, B, R) and it seems probable 

 that this peculiar body, which is identified by von 

 Winiwarter with the " cristalloide de Lubarsch " 

 (Lubarsch, 1896), is present in every cell of this 



