46 Wager and Pe7iiston.—Cytological Observations on 
At a later stage they react slightly, or not at all with the osmic acid of 
Flemming’s fluid, and seem at this stage to be of a purely proteid character. 
The cytoplasm takes a diffuse stain with haematoxylin, due to a chromatin¬ 
like substance diffused through it, with a very deep stain at one or more points 
in the cell. Frequently a deeply staining, homogeneous corpuscle is present, 
which is neither a nucleus nor a nucleolus. Several of these, of small size, 
may be present in a cell, but cells are found without a trace of them. 
In some cells one may find a vacuole whose wall is rich in stainable 
material at one side of the corpuscle. In the cells of Saccharomyces 
Ludwigii cultivated in the sap of the Ironwood tree, fixed with Flemming’s 
fluid and stained with iron-alum haematoxylin and eosin, the corpuscle was 
frequently demonstrated as a reddish body, having at times a tint of blue 
violet and surrounded by granules and elongated masses of chromatin. 
Sometimes, in corrosive sublimate preparations stained with very dilute 
solutions of haematoxylin, the corpuscles may be unstained, or stained 
no more deeply than the cytoplasm. He regards the garland-like chromatin 
structure as quite the same as the membrane of fine granules in contact 
with the nucleolus described by Wager (’98), though it does not appear to 
be as uniform as Wager figures it. The micro-chemical reactions for iron 
and phosphorus demonstrated the presence of masked iron and organic 
phosphorus in the corpuscle, in the wall of the vacuole in contact with it, 
and sometimes in the granules found in it and in the cytoplasm generally. 
The reaction is usually intense in the corpuscles, less strong in the cyto¬ 
plasm. In the process of budding the corpuscle becomes elongated and 
constricted in its middle portion. One or both parts may pass into the 
bud or both may remain in the mother-cell. In sporulation, the cyto¬ 
plasmic chromatin collects in the immediate neighbourhood of the corpuscle, 
which also undergoes certain granular changes, then elongates with con¬ 
striction in its middle part. It may be compared to the division of the 
nucleolus in Eugle?ia viridis , but is not of the nature of true karyo- 
kinesis. 
Hoffmeister (TO), whilst agreeing that the nucleolus is a spherical 
homogeneous body, considers that it must be regarded as a true nucleus. 
Guilliermond (’ 02 , ’04) found all the structures described by Wager, but 
disagreed with his interpretation. He states that:—( 1 ) the nucleolar body 
(nucleus of the older observers) is not always attached to the vacuole, ( 2 ) it 
possesses in itself the ordinary structure of a nucleus, consisting of a nuclear 
membrane, nucleoplasm, and network with sometimes an indication of 
a nucleolus, and ( 3 ) the nuclear vacuole does not contain anything of the 
nature of a chromatin granular network, but that the granules contained in 
it correspond to the red granules of Biitschli and are composed of meta¬ 
chromatin, which may be regarded as a kind of reserve material. He 
agrees, however, that the nucleus (nucleolus) divides directly, and that, 
