534 Wager. — The Nucleus of the Yeast- Plant. 
of the nucleus. At a later stage these two nuclei disappear, 
but in their place a single large nucleus is found. From 
this they come to the conclusion that the two nuclei fuse 
together again, and that the process may be regarded as 
a conjugation of two nuclei, transforming the cell into an 
egg, ‘ Ces deux noyaux , en se conjuguant , transforment cette 
cellule en un ceuf! As I have shown above, their first two 
nuclei are produced by division of the vacuole, their single 
large nucleus found at a later stage is probably the nucleolus. 
In the cell at this stage the protoplasm is uniformly 
stained rather more deeply than the nucleolus. In preparations 
stained with gentian-violet, the nuclear body is light blue, 
the protoplasm reddish blue, with a number of minute 
granules scattered through it. 
This stage gradually passes into one in which the peri- 
pheral layer of the protoplasm loses its capacity for stains, 
leaving the central portion more deeply stained than before 
(Fig. 55). Numerous deeply-stained granules at the same 
time appear, chiefly around the outside of the deeply-stained 
central protoplasmic mass (Figs. 56, 57). This stage appears 
to correspond with that stage in the living condition of the 
cell which has been described as a condensation of the pro- 
toplasm either towards the centre or to one side of the cell. 
At the same time the nucleolus itself undergoes a change. 
Its central portion becomes more deeply stained than its 
peripheral portion (Fig. 56), presenting an appearance 
strikingly similar to that which I have observed constantly 
in the nucleoli of sections, stained with gentian-violet, of the 
root-apex of Phaseolus , just previous to the formation of the 
chromosomes. This stage is succeeded by one in which the 
central deeply-stained mass of protoplasm decreases in size, 
and at the same time the central deeply-stained granular 
mass in the nucleolus becomes larger (Figs. 57 > 5&). We 
are I think justified therefore in concluding that the increase 
in the stainable material of the nucleolus is due to the 
absorption of stainable substance from the surrounding 
protoplasm. 
