82 
Wager and Penis ton,—Cytological Observations on 
partially separated from the nucleolus, and portions of the chromatin network are shown still 
attached to the nucleolus in Figs. 90 and 91. 
Fig. 94. Brewery yeast, after four hours in Pasteur’s solution, foam, fixed in Perenyi’s fluid. 
The granular structure of the chromatin shows clearly; the nucleolus presents a curious appearance, 
resembling the telophase of mitotic division. The volutin granules inside the vacuole are stained 
(haematoxylin). 
Fig. 95. Brewery yeast, after five hours in 5 per cent, sugar solution, stained with brazilin. The 
nucleolar substance appears to be drawn out into the threads of the chromatin network. 
Figs. 96-8. Brewery yeast, forty-eight hours in Pasteur’s solution, foam, fixed in a mixture 
of equal parts of Flemming’s and Perenyi’s solutions. The structure of the nucleus shows clearly ; 
the contents of the nuclear vacuole are more deeply stained than the cytoplasm. 
Fig. 99. D.C.L. compressed yeast after four hours in 5 per cent, sugar solution. The chromatin 
network shows clearly attached to an elongate nucleolus. The latter with a group of deeply 
stained granules at each end strongly resembles a mitotic figure. 
Fig. 100. Transverse section of the cell of Closterium , showing the nucleolus with chromatin 
patches on the surface. 
Fig. 101. Budding cell showing the structure of the chromatin network and its morphological 
relation to the nucleolus. 
Fig. 102. Yeast cell, after two hours in 5 per cent, sugar solution, mounted in glycerine; 
showing the structure of the nucleus. 
Fig. 103. Structure of nucleus ; the nucleolus is seen through the chromatin network. 
Fig. 104. Yeast cell, after fifteen hours in Pasteur’s solution, stained with safranin and gentian 
violet ; shows the structure of the nucleus. The granules are small and evenly distributed on the 
threads of a complicated network. 
Fig. 105. Cell with nucleus. The chromatin network is simple, consisting of few threads 
bearing few granules; the origin of these threads from the nucleolus is clearly shown. 
Figs. 106, 107, and 108. Budding cells, showing typical stages in the division of the nucleus. 
Fig. 109. Yeast cell, after five hours in 5 per cent, sugar solution, stained with brazilin. The 
chromatin network is compressed, probably by the glycogen present. 
Fig. no. After thirty-seven hours in Pasteur’s solution, bottom, showing a cell almost full of 
glycogen. 
Figs, in and 112. Old cells; Fig. in is from a five hours’ culture in 5 percent, sugar solution, 
stained in brazilin. 
Figs. 113, 114, and 115 represent the initial stages of spore formation in ‘Town Hall’ 
compressed yeast. 
Fig. 113. The contracted chromatin network. 
Fig. 114. A slightly later stage; the nucleolus is seen through the contracted network and 
appears as if surrounded by granules. 
Fig. 115. A still later stage, showing granules in close proximity to the nucleolus. One strand 
of the network remains. 
Fig. 116. Drawn from a preparation of brewery yeast, fixed in Perenyi’s fluid after forty-eight 
hours in Pasteur’s solution (foam), to show the volutin granule inside the vacuole. 
PLATE IX. 
Figs. 117-30. Cells in which the phosphorus reaction is shown; the colour is slightly deeper 
than is visible under the microscope. 
Figs. 117-22. Cells from bottom after two hours’ fermentation. 
Figs. 123-7. Cells from bottom after ten hours’ fermentation. 
Figs. 128, 129, and 130. Cells after five hours in 5 per cent, sugar solution. 
Figs. 131-50. Glycogen. 
Figs. 131-9. ‘Town Hall’ compressed yeast stained with iodine; Figs. 131-5, after five 
hours in 15 per cent, sugar solution, showing early stages in appearance of glycogen. 
Figs. 136-9. After eight hours in 15 per cent, sugar solution, showing later stages in the 
ormation of glycogen. 
Figs. 140-3. Brewery yeast from bottom, after 409I hours’fermentation, showing cells containing 
a large quantity of glycogen. Stained in methyl green, followed by iodine and examined in water. 
