484 TRANSACTIONS OF THE CANADIAN INSTITUTE, [VoL. VI. 
originally present have fused or conjugated, that is, fecundation has 
taken place. This is followed by division of the large nucleolus, the 
elongation taking place in the long axis of cell. In each of the two 
nucleoli thus formed a second division occurs, immediately following 
the first, the elongation of the two daughter nucleoli being at right 
angles to each other. When the four nucleoli are fully formed the 
membrane develops about each, and around each of the nuclei thus 
constituted the protoplasm collects, a membrane finally forming about 
each mass, which becomes a spore. 
According to Buscalioni, whose observations were made on S. guttu- 
latus, the yeast cell contains a nucleus which ordinarily is homo- 
geneous, and its division is by constriction. This obtains when budding 
occurs, the two daughter nuclei remaining connected by a thin fibril 
until one of them enters the bud. This is simple fragmentation. In 
the formation of spores, however, the nucleus undergoes a slightly 
different species of division which may be looked upon as a rudiment- 
ary kind of kinesis. 
Bouin found a sharply defined nucleus which, during fermentation,sends 
prolongations into the cytoplasm. The latter are less sharply defined 
the further they proceed from the centre of the nucleus. The nucleus 
ordinarily may be granular, or may contain in its interior irregular, 
deeply stainable masses. In some cells a nucleus would appear to be 
absent. In these an intense stain may serve to show a nucleus poor in 
chromatin ; but cells which do not appear to have a nucleus have lost it 
by its transference, without division, into the bud. The nucleus may, 
under certain conditions, divide and re-divide, while the cell may remain 
undivided, and Bouin holds. that this multiple division of the nucleus 
accounts for the number of chromatin granules found in some yeast 
cells. The granules are, in this case, nuclei, and the cell containing 
them, multinucleate. The division of the nucleus ordinarily 1s amitotic, 
that is, there is elongation of the nucleus with constriction, the thread 
uniting the two ends becoming more and more delicate till rupture 
occurs. One of the two daughter nuclei thus formed passes through 
the canal between mother cell and bud, and into the latter, where it 
becomes spherical. No striation of the cytoplasm between the two 
daughter nuclei was observed, nor was any evidence of an equatorial 
plate and of chromosomes found. In the formation of spores the 
nucleus divides into two chromatin masses, which separate, then become 
rounded, and constitute the nuclei of the spores. This mode of division 
is intermediary between mitosis and amitosis. 
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