STUDIES OF AMITOSIS 497 



Vom Rath ('91, '93) finds amitosis in the spermatogonia of 

 amphibians, but he regards those cells dividing in this way as 

 not becoming spermatozoa, but as degenerating and later being 

 used as nutritive material by the other spermatogonia. His 

 view on amitosis is therefore similar to those of Ziegler and 

 Flemming. 



Meves ('91, '94, '96) says that the spermatogonia of Salmandra 

 divide by amitosis in the autumn, but return to the mitotic di- 

 vision in the spring, and later they give rise to functional sper- 

 matozoa. He believes, therefore, that amitosis also falls in the 

 generative series of cell-division. 



Lowit ('91) claims that there is a generative amitosis, at least 

 in the case of leucocytes, although a good many other cases of 

 amitosis may be of a degenerative nature. He suggested that 

 two kinds of amitotic divisions — generative and degenerative — 

 might be distinguished. 



Ziegler ('91) and Ziegler and vom Rath ('91) assert that 

 amitosis takes the place in such cells as are undergoing intense 

 secretory or assimilatory processes and have large nuclei, and 

 that the division process is usuall}- limited to the nucleus. They 

 believe that this kind of nuclear division is always a forerunner 

 of degeneration and death. 



Verson ('91) observed the direct nuclear division of the large 

 cell in the bhnd end of the testicular foUicle in Bombyx, and he 

 considered that this cell gives rise to true sex-cells. 



Frenzel ('91), in his work on the intestinal glands of the cray- 

 fish, came to the conclusion that the amitosis occurring there is 

 a normal method of cell-multiplication. 



Flemming ('92) reviewed all of the Hterature on amitosis up 

 to his time and maintained in a general way his hypothesis as 

 regards to the significance of this process. 



Gerasimoff ('92, as cited by Wasielewski, '03, '04), has shown 

 that certain external conditions may effect the method of cell- 

 division. He observed that mitosis in Spirogyra takes place 

 by amitosis when this plant is placed in low temperature. 



Paladino ('93, as cited by Des Cilleuls ('14), '95) observed 

 that the new formation of the placenta in Mammalia is mainly 



JOUKNAl. OF MORPHOLOGY, VOL. 30, NO. 2 



