Wager . — The Nticleus of the Yeast-Plant. 521 
The moving particle or nucleolus stains in the ordinary 
nuclear stains, and is supported to the wall by a caryoplasm 
of delicate threads. 
These observations of the authors mentioned are in so far 
correct that, as previously stated, a vacuole with the structure 
they describe occurs in young cells ; but whether it should 
be regarded as a nucleus or not is a question for further 
consideration. The presence of the nuclear body described 
by previous observers seems to have escaped their notice in 
the younger cells, although they have apparently seen it 
in older cells, for the body in these cells which they describe 
as the nucleolus is doubtless in many cases the nuclear body 
of previous observers. But as I have shown, by appropriate 
staining both a nuclear body as well as a vacuole can be seen 
in all cells which contain the latter, except in quite young 
buds ; and when the nuclear body is seen through the vacuole 
we get an appearance which recalls at once the structure of 
the nucleus in higher plants (Fig. 7 ). 
That there is reason for regarding the vacuole as possessing 
some of the attributes of a nucleus will be seen in what 
follows ; for both Eisenchitz (’95) and Macallum (’95) had 
given indications of such a possibility in their memoirs ; and 
I was able also to show (’9 7) that in addition to the nuclear 
body, there is a granular network present in the cell in close 
contact with it which resists the action of digestive fluids and 
is coloured intensely by nuclear stains. 
In order to see the exact relation of the nuclear body to 
the vacuole it is necessary to examine Yeasts at different 
stages of fermentation, for there are two kinds of vacuoles, 
if we may speak of them as vacuoles — nuclear vacuoles, as 
I propose for the present to call them, and glycogen-vacuoles. 
The former are visible most clearly in Yeast-cells during the 
first few hours of fermentation ; the latter are gradually 
formed as fermentation proceeds, and are generally of such 
a size as to completely fill the cell, leaving the nuclear body 
and a thin lining layer of protoplasm on the wall of the cell. 
Yeast-cells taken three hours after the commencement 
N n 2 
