Pollen Mother -cells of Lilium canadense . 2 1 1 
a gradual increase in the total amount of fibrous material in the nucleus 
down to the time of the disappearance of the nuclear membrane. An 
indication of this increase of fibrous material appears in Fig. 32, drawn 
from iron haematoxylin material ; but it is much more noticeable in 
preparations treated with the triple stain. The fibres are granular and 
usually crooked or wavy. Some of the longer ones are now seen to 
connect separate chromosomes ; others run from the chromosomes to the 
nuclear membrane, and often seem to be continuous through the membrane 
with cytoplasmic fibres. Very short fibres are sometimes attached to 
the nucleoles, but the latter commonly appear quite detached from other 
nuclear substances. The chromosomes now stain distinctly red in the 
triple stain, and, leaving out of account the blue-staining fibres, which 
cause the ragged appearance mentioned, each chromosome has a somewhat 
uneven or undulating outline (Figs. 33-54). 
The nucleoles remain generally spherical, sometimes appearing 
elongated, and, as time goes on, not uncommonly showing one or more 
small bud-like attachments (n, Fig. 32), plainly of nucleolar matter. In 
stages still later than that of Fig. 32 the number of intra-nucleolar vacuoles 
increases ; the nucleoles show a decreasing affinity for the safranin and 
an increasing affinity for the orange. In the latter part of the period 
of chromosome development, but before the initiation of the cytoplasmic 
processes which directly result in the formation of the spindle, the nuclear 
membrane begins to lose its smooth, even appearance, becoming more 
or less granular and irregular or wavy in outline. Just before the dis- 
appearance of the nuclear membrane, the two or three nucleoles usually 
present in the nucleus up to this time break up into a much larger number 
of bodies, which appear as rounded droplets scattered through the nucleus. 
If the nucleole has retained its affinity for the safranin up to the time 
of its fragmentation, these small nucleoles appear at first red ; but, as 
shown by preparations in which a succession of stages appears in the 
same anther sac, their staining power often gradually diminishes. 
When the nuclear membrane gives way, and the cytoplasmic fibres 
push into the nuclear cavity, the chromosomes aggregate into a close, 
irregular mass at the centre of the cell (Fig. 55, PL VIII). At the same 
moment the small nucleoles already spoken of disappear, and there appear 
in all parts of the cytoplasm a great number of still smaller, rounded, 
usually red-staining bodies. It seems quite certain that these granules 
result from a second fragmentation of the nucleolar material and its 
extrusion, perhaps in a state of solution, into all parts of the cell. Up 
to this time the chromosomes have retained their ragged appearance, 
due to the attached fibres ; but from the beginning of the transformation 
of the multipolar into the bipolar spindle, the chromosomes appear with 
smooth outlines and with fibres attached to them only in bundles and 
