Wager.— The Nucleus of the Yeast-Plant. 507 
passed through, when it divides completely, and the two 
nuclei thus formed separate from each other towards the 
opposite sides of their respective cells. In the process of 
spore-formation the nucleus divides into four, each becoming 
the nucleus of a spore. 
Janssens and Leblanc (’98) state that all cells of Yeast 
contain a nucleus which possesses a membrane, caryoplasm, 
and a nucleinated nucleolus. At the commencement of 
fermentation the nucleus is vacuolized, and presents the 
appearance of a vacuole containing a little sphere animated 
by Brownian movements. In the process of budding the 
nucleus divides indirectly in some cases, directly in others. 
In S. Cerevisiae the nucleolus is divided into two in the 
mother-cell in the neighbourhood of the bud. In the cells 
which are about to form spores one finds two nuclei. These 
use together, and the result is practically a fertilized egg- 
cell. This nucleus then divides by a reduced process of 
karyokinesis. This division is again repeated, and four 
nuclei are formed, each of which forms the nucleus of 
a spore. 
Bouin (’98) states that the Yeast-cell contains in its normal 
condition a distinct nucleus. During fermentation this 
nucleus loses its clearness, and by putting out prolongations 
more or less clearly defined, it comes into close relation 
with the cytoplasm of the cell. Under the influence of an 
exaggerated concentration of the nutritive solution, or a 
reduction in the mineral elements, or by an increased tempera- 
ture, the cells increase in size and become plurinucleate. This 
explains the observations of Hieronymus and others. The 
granules observed by these authors represent the nucleus 
which has become divided by a series of divisions not 
followed by cellular divisions. In the process of budding 
the nucleus divides more often directly than indirectly, but 
sometimes during budding, and always in the formation of 
spores, the division partakes of the indirect method. 
In a recent paper, Macallum (’98) described a new method 
for the detection of combined phosphorus in tissues, and 
