2 38 Campbell \ — Contributions to the 
• the secondary nuclei also divide before moving to the apex of 
the spore I cannot say, as the next youngest stage observed 
had four free nuclei, and these lay in the apical part of the 
spore, with no indication whether they had assumed this 
position before or after the division of the secondary nuclei. 
These nuclei were much smaller than the primary one which, 
however, they resemble in structure, except that they have 
relatively more chromatin than the nucleus of the resting 
spore. They lie close to the periphery of the spore, and the 
surrounding cytoplasm is much more finely granular than that 
of the interior of the spore, and colours much less strongly 
with gentian-violet. 
The nuclei now divide rapidly, becoming at the same time 
much smaller, until a considerable number (usually from thirty 
to fifty) of free nuclei are formed ; but as yet there is no trace 
of division-walls between them. By far the larger number of 
the nuclei lie in the upper part of the spore, but sometimes an 
occasional one may be detected in the basal part or centre ; 
but these portions are usually destitute of nuclei at the time 
when cell-formation begins. For the demonstration of the 
nuclei at this time, the sections should be overstained with 
gentian-violet, and the superfluous colour removed with alco- 
hol. In this way the nuclei remain strongly coloured after 
the cytoplasm is entirely decoloured. 
The first trace of cell-formation is at the apex of the spore. 
At this time the cytoplasm colours more deeply than before, 
and sometimes very delicate threads may be detected, radi- 
ating in all directions from the nuclei and connecting the 
adjacent ones (Fig. 8). Shortly after, the first traces of the 
division-walls appear simultaneously between the nuclei, in 
the form of cell-plates composed of minute granules (micro- 
somes), presumably of cellulose. The separate microsomes 
quickly coalesce and form the continuous membrane of the 
young cell- wall. In this way the upper part of the spore be- 
comes transformed into a solid tissue (Figs. 9, 10). 
The cell-formation proceeds quickly toward the base of the 
spore, following the spore-wall, so that for a time the central 
