the Yeast Plant. 
65 
and of A. Meyer (’ 04 ), and contrary to Guilliermond’s emphatic statement, 
that the volutin granules lie for the most part in the cytoplasm outside the 
vacuole, though, as Meyer points out, often in close proximity to the vacuole 
wall. One large granule, or two, more rarely three, smaller granules which 
have some of the characteristics of volutin commonly occur within the 
vacuole, and these usually exhibit the characteristic Brownian movements. 
Guilliermond himself seems to be in some doubt as to their exact loca¬ 
tion. On p. 105 of his Memoir (’ 92 ) he says, ‘ Dans les premiers stades, 
la levure est constitute d’une vacuole renfermant des corpuscules meta- 
chromatiques.’ On p. 261 he says, ‘ Ces corpuscules, qui correspondent 
aux granulations chromatiques decrites par certains auteurs (Raum, Eisen- 
schitz, Curtis, Wager), sont presque toujours localises dans l’interieur des 
vacuoles. On peut en rencontrer cependant dans le protoplasme et ils 
paraissent tous etre d’origine protoplasmatique.’ 
Kohl’s account (’ 09 , p. 37) is that the granules lie in greater or less 
number in the cytoplasm, often crowded together on the walls of the 
vacuoles. In healthy cultures he found only one or two granules in each 
vacuole, and a few small ones in the rest of the cytoplasm, which might 
possibly be situated in small vacuoles. He considers that this would accord 
with most of the figures given by Guilliermond (’ 02 ). It is, however, not 
easy to see on what grounds Kohl makes this statement, for an examination 
of Guilliermond’s figures (Plate X, Figs. 1-25) shows the volutin granules 
almost exclusively in the nuclear vacuole. 
The amount of volutin present varies according to the stage of develop¬ 
ment and the metabolic activity of the cell (Figs. 5-7 and 163-82). In 
yeast obtained fresh from the Albion Brewery we usually found but little 
volutin (Figs. 163-4). In some cases the granule in the centre of the 
vacuole and a few small granules in the cytoplasm gave the volutin re¬ 
actions, but in others no reaction was obtained, although the central 
granule was present and clearly visible in the living cell and in the un¬ 
stained fixed specimens. 
During the first five hours’ fermentation in Pasteur’s solution or in 
a strong sugar solution, we find that a slight but perceptible increase takes 
place (Figs. 167-8), which usually becomes marked after about ten hours, and 
under good conditions continues progressively till a maximum is reached in 
40-50 hours (Figs. 179-80). After this the volutin decreases, and with the 
other cell contents becomes limited to a small space in the cell by the en¬ 
croaching glycogen (Fig. 182). A considerable quantity of volutin is 
usually present at the end of fermentation, and so long as the cells remain 
apparently inactive this volutin decreases with extreme slowness. 
Guilliermond states that these granules may persist for a considerable 
time, and that he found them still present in yeast which had been kept 
for three months in distilled water. We find in the case of old cultures 
F 
