No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 381 
internodal cells, become multinucleolar ”; the nodal leaf cells 
proceed in the same way. From these observations Macfarlane 
concludes: “ in every active embryonic cell one nucleolus only 
is present in the resting state ”; in some cases a fluid globule 
is present in the nucleolus, and this probably represents a 
“ degradation of the endonucleolus.” “ The nucleolus, or more 
probably the nucleolo-nucleus, is the center of germinal activity, 
and that as we pass outwards to the periphery of the cell, this 
reproductive activity becomes less and less. . . . The result is 
that in all plants thus examined, after cell division has ceased, 
continued division of the cell contents from the endonucleolus 
outwards goes on. ... I venture, therefore, to regard it as a 
general principle that after cell formation has ceased, the cell 
contents (especially the endonucleolus and nucleolus) persist 
in their activity for a shorter or longer period; . . . the most 
exalted type of cell is one with abundant protoplasm containing 
a single nucleus, nucleolus, and endonucleolus; ... a cell with 
vacuolated protoplasm, one nucleus and two to four nucleoli 
is less exalted, while the multinuclear state is the most degraded 
form of cell.” 
Zacharias (’ 85 ) gives critical reviews of numerous preceding 
papers on nucleoli, besides observations of his own on various 
cells of plants. Galanthus nivalis , cells of the inner layer of 
the “ Fruchtknotenwand ”: the single nucleolus is about tV the 
size of the nucleus; examined in water it is homogeneous; after 
the action of absolute alcohol it appears to be composed of 
granules of various indices of refraction. Bast cells of Cucurbita 
pepo : the nucleoli, when stained with “ Blutlaugensalz-Eisen- 
chlorid,” become very intensely colored, while the remaining 
nuclear substance stains only faintly. In the cells of Spirogyra 
and of the asci of Lichens he finds that there are no “ nucleoles- 
noyaux,” such as Carnoy described. “ Alle Autoren stimmen 
gegenwartig darin iiberein, dass die Nucleolen bei der Kern- 
theilung verschwinden.” In opposition to Strasburger he 
contends that during the mitosis the dissolved nucleolar sub¬ 
stance might as probably enter into the formation of the spindle 
fibers as of the chromosomes. In Chara (observed living) each 
nucleus contains one large nucleolus, with vacuoles : “ Naht 
