34 ' BOTANICAL GAZETTE [jaxltary 



and 



The second divi- 



chromosomes 



therefore equational {fig. j/). The daughter nuclei are now recon- 

 structed. A large dark nucleolus appears in each, while the rest of 

 the nucleus is occupied by a linin network and scattered chromatin 

 granules. Fig. j8a would seem to indicate that these granules are 

 formed by the breaking-up of larger clumps. The nucleolus stains 

 red, the network purplish with safranin and malachite green.. During 

 mitosis the chromosomes are bright red, but after reconstruction thb 



lually lost. The cytoplasm, which has remained undivided, 



1 



erra 



(fig 



DISCUSSION 



The nucleolus.— This term, in its limited sense, has 



within 



shape 



m 



g rniHke the chromatin (Wilson 12). The great diversity 



on the behavior of this body has given rise to 



concemmcr its oncrm and function. Mon 



com 



and animal cells 



mention a Iars:e number of authors whose 



them to believ 



ported 



formation of chromatin. This view is sup- 



mi 



of nucleolus and 



chromatin, but also by researches on their chemical relations. Another 



has somethins: 



O 



tion. Str.\sbiirger (9) and Nemec (7) adopt this view. Many 

 ^Titers on the Protista ako report kinoplasmic material arising from 

 the nucleolus. A thu-d theor}^ maintains that the nucleolus contains 

 material which is periodically expelled into the cytoplasm. By some, 



CKER (3), this is considered an excretory function. OtheK 



; correlated with the appearance in the 



believe tha. „_ t...^..^...^..^u. , 

 cytoplasm of substances havin 



IMy ovm observation^ afford support to the first of the explanations 

 outlined above. The growth in size of the nucleolus simultaneously 

 with the appearance of darkly staining granules in the nucleus, the 

 accumulation of this material in the nucleolus, and its expulsion, 



