the Yeast Plant . 
81 
Figs. 20 and 21. The same yeast, 40-45 hours in Pasteur’s solution, foam, showing a much 
smaller vacuole. 
Fig. 22. The same yeast, 40-45 hours in Pasteur’s solution, bottom; the vacuole has disappeared, 
and the cell apparently contains nothing but a number of refractive granules at one side. 
Figs. 23-6. Fresh yeast cells, similar to those figured in Figs. 1-3, after 1-4 hours in distilled 
water. 
Figs. 27 and 28. The same after twenty-four hours in distilled water. 
Figs. 29-56 show the effect of a number of fixing fluids on the fresh yeast figured in Figs. 1, 2, 
and 3. Figs. 29-31, Gram’s iodine solution. Figs. 32, 33, and 34, Flemming’s weaker fluid. Figs. 
35 an d 36, Perenyi’s fluid. Figs. 37 and 38, corrosive sublimate, concentrated aqueous solution. 
39> 4°> and 41, corrosive sublimate, concentrated aqueous solution in 70 per cent, alcohol with 
the addition of 5 per cent, glacial acetic acid. 
PLATE VII. 
Fig. 41. Corrosive sublimate. See above. 
Figs. 42-4. Alcohol 30 per cent. 
Figs. 45-7. Absolute alcohol. 
Figs. 48, 49. Picric acid ; concentrated solution in 5 per cent, alcohol. 
Figs. 50-2. Picric acid ; concentrated solution in 70 per cent, alcohol. 
Fig- 53- Brewery yeast, after five hours in Pasteur’s solution, stained with Fleidenhain’s haema- 
toxylin and methylene blue. The nucleolus has a deeply stained patch in surface view. 
Fig. 54. D.C.L. compressed yeast after four hours in sugar solution (5 per cent.); nucleolus 
with deeply stained patch. 
Fig- 55. Brewery yeast, after twenty-three hours in Pasteur’s solution, fixed in Perenyi’s fluid. 
The nucleolus is seen in surface view, with two deeply stained patches. Here, as in the two 
preceding figures, the nucleolus substance appears to be drawn out into the threads of the chromatin 
network; the nuclear vacuole in each case is pressed out behind the nucleolus and appears to 
surround it. 
Fig. 56. ‘Town Flail’ compressed yeast, fresh, showing nucleolus with irregular deeply 
stained patches. The chromatin network is obscured by the densely stained cytoplasm. 
Figs. 57 and 58. Cells which have maintained a feeble fermentation for four hours in an insuffi¬ 
cient supply of wort. In each case, the nucleolus is faintly stained and the cytoplasm deeply 
stained; the deeply stained patch on the surface of the nucleolus is the only part of the cell strongly 
differentiated. 
Fig. 59. Brewery yeast, fresh, showing a curious appearance of the nucleolus, caused by the 
deeply stainable substance on its surface. The nucleolar substance appears to be drawn out into 
the threads of the chromatin network. 
Fig. 60. Brewery yeast, after twelve hours in a limited supply of wort; shows a faintly stained 
elongate nucleolus with a deeply stained patch at each end, strongly resembling a mitotic figure. 
Figs. 61-4. Brewery yeast, fixed in 30 per cent, alcohol after feebly fermenting for four hours 
in an insufficient quantity of wort. The stain was reduced to differentiate the granules on the surface 
of the nucleolus. 
Figs. 65-76. D.C.L. compressed yeast. The figures show appearances most strongly sug¬ 
gestive of nuclear structure and mitotic phenomena. They were selected from a single example 
of D.C.L. and are remarkable for the peculiar distribution of a large amount of deeply stainable 
substance on the surface of the nucleolus. The cytoplasm in most cases was densely stained, 
obscuring the structure of the vacuole. 
Figs. 77-80. Brewer’s yeast, after two hours in an insufficient quantity of wort. 
Fig. 77. Cell showing an elongate nucleolus with a deeply stained patch at each end. 
Fig. 78. Cell containing a nucleolus with two deeply stained patches, farther apart than in the 
preceding figure. Fig. 80, cell containing two nucleoli each possessing a deeply stained patch. 
PLATE VIII. 
Fig. 81. Cell showing nucleolus dividing. 
Figs. 82-93. Nucleoli which have been pressed out of the cells. Fig. 82, the dividing 
nucleolus actually pressed out of the cell figured in Fig.81. Fig.83 shows the deeply stainable substance 
G 
