498 WARO NAKAHARA 



due to amitotic cell multiplication, and maintained the view that 

 this kind of division is a normal physiological process. 



Toyama ('94) found that the cells, including Verson's 'large 

 cell' (Verson's cell), which divide amitotically in the testicular 

 follicles of silk worms do not belong to the cycle of true germ 

 cells, but finally degenerate, thus supporting the view of Ziegler, 

 Flemming, etc. 



Krompecher ('95) in his work on bone-marrow, came to the 

 conclusion that only mitosis can be considered as generative 

 division, and amitosis must be regarded' as a breaking down of a 

 degenerating nucleus. 



Preusse ('95) arrived at the conclusion that nuclei of oogonial 

 cells may divide by amitosis, yet afterward undergo normal 

 mitotic division, in the case of some hemipterous insects. 



Wilcox ('95) in his study of spermatogenesis of Caloptenus 

 and Cicada, observed that 'giant spermatozoa' which are pro- 

 duced from spermatogonia by amitotic division are not func- 

 tional, and "really come to naught," being excluded from the 

 developmental series. He, therefore, stands in support of the 

 degeneration theory. 



Plate ('98), studying amitosis in the tracheal epithelium of 

 Janelles, expressed his opinion that this kind of division is a proc- 

 ess of multiplication often in the dying condition of the cell. 



de Bruyne ('99) supports the view advanced by Ziegler and 

 vom Rath in the case of amitosis in the ovarian follicle of Hemip- 

 tera and Orthoptera. 



Pfeffer ('99, according to Wilson, '00, Wasielewski, '03, '04, 

 et cetera) showed experimentally that amitosis is a result of 

 special environmental conditions. He saw that the cells of 

 Spirogyra placed in water containing 0.5 to 1.0 per cent of ether, 

 undergo amitotic division, but resume mitotic division when 

 the same individuals were transferred into normal water. 



McGregor ('99) noted in Amphiuma the fact that the primary 

 spermatogonia divided by amitosis, divide by mitosis later and 

 produce functional spermatozoa, and thus he supports the view 

 of Meves. 



Hacker ('00) was able to induce amitosis in the eggs of Cyclops 



