64 WARO NAKAHARA 



3. The migration of the nucleoh is continued throughout the 

 entire history of the functional cell. 



4. The number of the nucleolar masses in the cell-body de- 

 creases after some amount of secretion has been discharged from 

 the cell. 



The facts enumerated above seem to lead to the conclusion 

 that the nucleoli constitute at least a part of the source of the 

 secretion products of the cell dealt with. 



B. Chemical 



Perhaps no one has paid more attention to the staining reac- 

 tion of the nucleoli and the changes in the reaction after the 

 material has passed out into the cell-body, than Walker and 

 other students of his school. 



In their paper on the migration of the nucleoli in the nerve 

 cells of mammals, May and Walker ('08) stained the material 

 with (A) basic fuchsin, followed by methylen blue and Unna's 

 orange tannin, or (B) safranin, followed by metheJyn blue and 

 Unna's orange tannin. In method A the nucleoli within the 

 nucleus stained blue or violet. They stain purple or red as they 

 pass through the opening in the nuclear membrane, bright red 

 or pink as they come to lie definitely outside of the nucleus, and, 

 as they travel away from the nuclear membrane, they are 

 always stained pink or red. Using the second method, they 

 observed that the nucleoli within the nucleus stain brilliant 

 scarlet, become reddish orange as they migrate, and turn pale 

 orange or yellow when they are completely extruded into the 

 cell-body. "This suggests strongly," the authors say, "that 

 some important chemical or physical change takes place in the 

 nucleolus when it passes into the cytoplasm." 



Walker and Embleton ('08) also made a similar observation 

 on the nucleolus of the cells of Hydra, employing the same com- 

 binations of stains, as Page May and Walker did. 



Working on the nucleoli of the vegetative cells of different 

 plants and animals. Walker and Tozer ('09) have made more 

 general statements as regard the staining reaction of the nucleoli 

 as compared to that of other elements of the cell. 



