Wager . — The Nucleus of the Yeast-Plant . 517 
glass or glass-slip and allowed to dry. A drop of the methyl- 
green and fuchsin mixture is then placed upon it and allowed 
to remain for two or three minutes. This is then washed 
off in water and the preparation examined in dilute glycerin 
under a one-sixth inch objective. The nuclear body will be 
seen coloured red and beautifully differentiated from the 
rest of the protoplasm, which remains colourless, or only 
slightly stained pink-blue. It is a perfectly homogeneous 
body even when observed under the highest powers of the 
microscope ; but it is sometimes surrounded more or less 
completely by granules, which are stained blue or blue-pink, 
and these give it, especially when seen with inferior glasses 
or illumination, a granular appearance. 
By means of haematoxylin it can perhaps be seen just as 
easily, but the preparation takes a longer time. I have 
found the following to be a good method. A cover-glass 
(or slip) preparation is taken prepared as above, and soaked 
for half an hour in a 2*5 °/ o solution of alum. It is then well 
washed in water and stained for half an hour in a -5°/ o aqueous 
solution of haematoxylin, and again well washed in water. 
It is now decolourized for half an hour or longer in the 
alum-solution and examined in dilute glycerin, or it may 
be passed through alcohols of various strengths and mounted 
in balsam. The nuclear body is by this method stained 
reddish blue or sometimes blue-red, and is beautifully differ- 
entiated from the protoplasm which remains very lightly 
stained. It is more clearly seen in dilute glycerin than in 
balsam. 
Every cell of the Yeast-plant, except quite young buds, 
contains one of these nuclear bodies ; very rarely are two to 
be found, except during budding or spore-formation. It is 
found in vigorously active Yeast, which has been fermenting 
for twelve hours, on one side of the cell, in close contact 
with the cell- wall ; in a few cells it may be seen in a more 
central position, but very rarely exactly in the centre of 
the cell. 
In cells which are stained very lightly, the nuclear body 
