the Yeast Plant. 
Fig. 144. Brewery yeast, from foam after 156 hours’ fermentation, showing glycogen inside 
nuclear vacuole. Methyl green followed by iodine and examined in water. 
Fig. 145. Brewery yeast, cell containing a maximum of glycogen, from bottom after 191 hours’ 
fermentation. 
Figs. 146 and 147. Stages in the disappearance of glycogen. Yeast in the condition figured in 
Fig. 145 was placed in fresh Pasteur’s solution ; after twenty-nine hours most of the cells presented 
the appearance figured (Figs. 146, 147). 
Fig. 148. Yeast fresh from brewery. 
Figs. 149 and 150. Brewery yeast after 10-15 hours’fermentation ; first appearance of glycogen. 
Fig. 151. The same yeast after twenty-nine hours’ fermentation. 
Figs. 152-6. Cells showing the reaction for masked iron; fresh D.C.L. compressed yeast; 
fixed in 30 per cent, alcohol: stained by Macallum’s haematoxylin method. 
Figs. 1 57 ~ 2 - Some of the colour effects obtained by temporary staining with methyl green 
and fuchsin. 
Figs. 157-9. Brewery yeast from foam after 156 hours’ fermentation. 
Figs. 160-2. Brewery yeast from bottom after three hours’ fermentation. In this case the 
cells were previously stained in Heidenhain’s haematoxylin and differentiated in Perenyi’s fluid. 
PLATE X. 
Figs. 163-82. Volutin in brewery yeast. The volutin granules are stained intensely in methy¬ 
lene blue and are represented in the figures as black granules. 
Figs. 163,164, and 165. Early stages in the appearance of volutin. In Fig. 165 the granules are 
outside the vacuole, in close contact with it. 
Fig. 166. Granule in nuclear vacuole, five hours in Pasteur’s solution. This is the only volutin 
granule in the cell. 
Figs. 167 and 168. Volutin granules after five hours in Pasteur’s solution. 
Fig. 169. After thirty-seven hours in Pasteur’s solution, fixed in Perenyi’s fluid and stained with 
Heidenhain’s haematoxylin, shows a volutin granule in the nuclear vacuole. 
Fig. 170. Cell from the same specimen of yeast fixed in iodine. Contains a large volutin 
granule in the vacuole. 
Fig. 171. The same fixed in iodine solution and showing an enormous volutin granule resting 
on the nucleolus. 
Fig. 172. Cell showing a number of volutin granules on the nucleolus. 
Figs. 173 and 174. After forty-four hours in a 5 per cent, sugar solution. 
Figs. 175 and 176. After ten and a half hours in Pasteur’s solution. 
Figs. 177 and 178. After thirty-one hours in Pasteur’s solution. 
Figs. 179 and 180. After forty-four hours in Pasteur’s solution ; a maximum amount of volutin 
is present. In Fig. 180 there is a dense, granular mass of volutin around the nucleolus. 
Fig. 181. After ninety-five and a half hours in Pasteur’s solution, foam. A large number of 
volutin granules around the vacuole. 
Fig. 182. After ninety-five and a half hours in Pasteur’s solution, bottom; the greater part of 
the cell is occupied by glycogen. 
