528 Wager . — The Nucleus of the Yeast-Plant. 
will be observed, differentiating the protoplasm and nuclear 
body and producing a clear definition of the glycogen-vacuole. 
General Considerations. 
We have thus seen that there are two structures in the 
Yeast-cell which together appear to represent the nucleus 
of the higher plants — the nuclear body and the nuclear vacuole. 
One of these — the nuclear body — is a permanent constituent 
of the cell ; the other is not. The nuclear vacuole, when it 
is present, possesses some of the attributes of the chromatin- 
network of the nucleus of the higher plants, and in many 
cases presents a remarkable resemblance to it. The chro- 
matin may be, and often is, very abundant. But the fact 
that the vacuole containing it may disappear, leaving the 
chromatin more or less completely disseminated through the 
protoplasm without the formation of chromosomes, except 
perhaps during the divisions leading to the formation of 
spores, seems to indicate that we are dealing with a body 
of much simpler construction than the nucleus of the higher 
plants ; and it may be that this nuclear vacuole represents 
merely a store of chromatin-material for the use of the cell. 
In the vegetative cells of other Fungi we appear to have 
at certain stages a similar structure. Vuillemin (Etudes 
biologiques sur les Champignons, p. 7) has shown that, in 
the hyphae of Entomophthora gtaeospora , one finds here and 
there, in contact with a nucleus, clear spheres surrounded 
by a delicate membrane, which are not to be regarded as 
vacuoles but as being of a nuclear nature ; and I have 
observed in the young hyphae of a Fungus, probably Mucor , 
a similar occurrence of chromatin-containing vacuoles. 
A careful examination of the vegetative cells of other 
members of this group of plants may possibly show that 
it is not uncommon. 
The structure which we have called the nuclear body 
resembles in many ways in its reactions the nucleolus of the 
higher plants ; and the fact that it may under certain con- 
