Fertilization in Finns Strobus. 463 
During an earlier study of the sporogeny of Pinns Strobus , 
similar colour-reactions were observed in connexion with the 
nucleoli. The occurrence of unstained nucleoli in the same 
nucleus in which others were deeply coloured was common, 
especially at about the time of synapsis. 
Various views are held regarding the nature of the nucleolus. 
We cannot here enter into a discussion of the voluminous 
literature dealing with the origin, function, and destiny of 
these structures ; but a few of the many views which have 
been advanced may be noted. 
Strasburger (’95, ’97, and ’00) expresses his conviction that 
nucleolar substance contributes to the formation of spindle- 
fibres. A similar view is held by Fairchild (’97), Harper (’97), 
Debski (’97), and other students of the Bonn Laboratory. 
Strasburger further holds that the nucleoli make active the 
spindle-forming substance in the cytoplasm, or that they 
enhance the activity of the kinoplasm. 
Flemming (’82), Humphrey (’95), Zimmermann (’93), Sargant 
(’96 and ’97), Duggar (’99), Mottier (’00), 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 
according to Karsten (’93), Lavdowsky (’94), and Wilcox (’95) 
they are centrosomes. 
Jordan (’93) states that ‘ their function is almost certainly 
one of nutrition either concerned in the storage or elaboration 
of nutritive material ’ ; Lukjanow (’88) and Macallum ( 91) con- 
sider 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. 
Fleming (’82), Zacharias (’85), and Zimmermann (’93) ascribe 
to the nucleolus the dignity of a nuclear organ ; and Mont- 
gomery ( 98) makes the following suggestion : ‘ That though 
