1898-99. } ON THE CYTOLOGY OF NON-NUCLEATED ORGANISMS, 493 
a few of such cells, in which the corpuscles were found to be deficient in 
chromatin. Buscalioni believes that yeast cells exist which are free 
from these bodies. Sometimes, on the other hand, one finds yeast cells 
also which contain not only one but several corpuscles, each, however, 
smaller than the single corpuscle of other cells. 
Very rarely in preparations of S. cerevis¢e but very frequently in those 
of S. Ludwigit as cultivated in the sap of the ironwood tree (Ostrya 
virginica), the corpuscle instead of being spherical and homogeneous, 
is irregular in contour and consists of one or more deeply stainable, 
dense granules, imbedded in a substance which constitutes the greater 
part of the corpuscle, and which is less markedly affected by dyes. 
Sometimes the irregularities in the contour may be so great as to give 
the corpuscle a stellate appearance. Bouin observed corpuscles of 
similar shape and structure in S. cerevisce and S. pastortanus. 
The corpuscle is the nuclear body of Errera and Wager, and the 
nucleus of Moeller, Bouin, Buscalioni and others. As these authors 
describe it, it divides by a process which is a simple form of karyokin- 
esis, and, therefore, it is in their view a fully developed chromatin- 
holding organ. According to Janssens and Leblanc the corpuscle is a 
nucleolus of a nucleus which can, by appropriate methods, be revealed 
as surrounding and containing the nucleolus. This nucleus further is 
provided with a membrane which becomes invisible when division of the 
nucleolus takes place, the caryoplasm also disappearing. 
In preparations hardened with iodine solution and stained with dilute 
hematoxylin, a body like the nucleus of Janssens and Leblanc can be 
observed surrounding the “ nucleolus,” but it is found only in a small 
number of cells, whereas in the greater number the “nucleolus” or 
corpuscle lies free in the cytoplasm. In preparations also made with 
Flemming’s fluid and stained with iron-alum hematoxylin, the corpuscle 
is rarely found to be included by a structure like that described by these 
authors, and when the latter is observed it contains no chromatin and 
does not give any evidence of structure in its interior. It isas such quite 
different from the corpuscle already referred to, to be found in S. 
Ludwzgit when cultivated in sap. What it is I am not certain, but | am 
inclined to regard it as a vacuole which, placed above or below the 
corpuscle, may with the latter strongly resemble a nucleus and nucleolus. 
In iodine preparations stained with iron-alum hematoxylin,the structure 
in question may be absolutely unstained while the “nucleolus” or 
corpuscle, and the cytoplasm are deeply coloured. On the other hand, 
one may find a vacuole, whose wall is rich in stainable material, overlie 
