108 MARGARET C. FERGUSON 



parison with that of the sperm-nucleus, is correlated with the 

 physiological role, as above suggested, which it plays in the 

 cell. We cannot, here, enter into a discussion of the volu- 

 minous literature dealing with the origin, function, and destiny 

 of the nucleoli ; but a few of the many views which have been 

 advanced may be noted. 



Strasburger ('95, '97 and 'oo) expresses his conviction that 

 nucleolar substance contributes to the formation of spindle- 

 fibers. A similar view is held by Fairchild ('97), Harper ('97), 

 Debsky ('97), and other students of the Bonn Laboratory, and 

 by Nemec ('99), Farmer ('94) and others. Strasburger ('95) 

 also sees indications of a connection between the nucleolus and 

 the cell-plate and he has recently ('97 and 'oo) sought to show 

 that the nucleoli make active the spindle-forming substance in 

 the cytoplasm, or that they enhance the activity of the kino- 

 plasm. 



Flemming ('82), Humphrey ('94), Zimmermann ('95), Sar- 

 gant ('96 and '97), Duggar ('99), Mottier ('oo), and many others 

 believe that the nucleoli represent reserve supplies of chromatin. 

 Dixon ('99) finds in them a vehicle of inheritance. Hirase ('98) 

 thinks that they give rise to the attractive spheres ; and accord- 

 ing to Karsten ('93), Lavdowsky ('94) and Wilcox ('95) they are 

 centrosomes. Rosen ('95) considers that the nucleoli are equal 

 in dignity to the chromatin, that they have no connection with 

 the centrosome and that they do not serve to nourish the chro- 

 mosomes. 



Jordan ('93) states that " their function is almost certainly one 

 of nutrition either concerned in the storage or elaboration of 

 nutritive material " and believes that there is substantial reason 

 for looking upon the nucleolus wherever found as concerned .in 

 one way or another with the active metabolism of the cell. 

 Lukjanow ('88) and Macallum ('91) consider the nucleoli to be 

 excretory organs which are intimately related to the nutritive 

 spheres of the egg, these spheres arising through a process of 

 deposition from the nucleolus. And Hacker ('93) observes that 

 the nucleolus is a contractile vacuole which absorbs proteid 

 substances ; the absorbed materials undergo a chemical change 

 within the nucleolus and are then periodically discharged. 



