504 WARO NAKAHARA 



tious roots of Stratiotes, observed amitosis in root-cap, cortex 

 and stole, and suggested that amitosis supplements karyokinesis 

 in this instance. 



McLean ('14), recording his observation that amitosis com- 

 monly occurs in the cortical parenchyma of aquatic angiosperms, 

 suggested that amitosis may be ''the constant form of nuclear 

 division between sister cells in all fully differentiated tissues 

 which remain alive and continue to grow in bulk, although this 

 does not preclude the possibility of its occurrence in meriste- 

 matic tissue as well." (P. 382.) 



Schurhoff ('15), demonstrating a beautiful case of amitosis in 

 the endosperm of Ranunculus, expressed his opinion that this 

 nuclear phenomenon does not lead to the formation of new cells, 

 and the motive to the process seems to be the enormous growth 

 of the endosperm nucleus. 



Macklin ('16) made a very valuable observation on the ami- 

 totic nuclear division in tissues (of an embryo chick) growing 

 in vitro. He asserted that amitosis is not a reproductive method, 

 because he found that the process involves only the nucleus and 

 not the cell-body, and whenever cell-division takes place, it was 

 always by mitosis. 



Saguchi ('17), working on the ciliated cells of different ani- 

 mals, maintained that these cells divide by amitosis only in 

 vertebrates. Contrary to the view of Jordan, he considered 

 "the occurrence of amitosis in ciliated cells is not owing to the 

 lack of the centrosome; for the latter can be detected in many 

 cases in such cells." He seems to believe that amitosis is a 

 method of cell-multiplication and the causes underlying amitosis 

 are due to the ''degree of differentiation of the cell-plasm." 



B. Discussion 



In looking over the literature discussing amitosis, as briefly 

 reviewed in the last section, one may notice the fact that many 

 authors have based their opinions more or less entirely upon 

 their own data, without paying much attention to the compati- 

 bility of their theories with other observed .facts. Another un- 



