TO 
> Sey a 
1898-99. | ON THE CYTOLOGY OF NON-NUCLEATED ORGANISMS. 491 
It is of course possible that granules which give the reaction with 
osmic acid do not consist wholly of fat, for the reaction in all cases is not 
intense enough to suggest a purely fatty composition. The basis of 
apparently all the granules seems to be a proteid substance which may 
vary in its particular character from stage to stage in the process of 
fermentation, and in these granules the fat which may be demonstrated 
is deposited. 
The structure of the cytoplasm varies. When the cells of S. Ludwgiiz 
of early stages of fermentation are hardened in Flemming’s fluid and 
stained in Heidenhain’s hematoxylin, we get an appearance like that 
illustrated in Figs. 36, 37, and 38. In these the cytoplasm is shown to 
contain a reticulum whose meshes are delicate and whose nodal points 
are thickened. In some cells, as for example in Fig. 38, the reticulum 
forms a ring around a cospuscle, whose nature will be discussed below. 
In other cases the reticulum is in intimate connection with the corpuscle. 
In corrosive sublimate preparations a reticulum is not readily observ- 
able, and this is due to the property the reagent has of fixing not only 
the reticular portion of the cytoplasm, but all the proteids in its meshes, 
whereas the acetic acid of Flemming’s fluid dissolves out some of these. 
Indications, however, of a reticulum can be found if the stain of the 
iron-alum hematoxylin is carefully decolourized with weak iron-alum 
solutions. 
When the cells have been prepared with iodine solution and stained 
with iron-alum hematoxylin the reticulum shown is coarser as a rule 
than in Flemming’s fluid preparations, the meshes are larger and the 
trabecule thicker. I am inclined to regard this result as due to the 
iodine reagent which fixes the cytoplasm slowly, and consequently 
may permit plasmolytic alterations. 
The presence of vacuoles affects only slightly the reticular structure, 
merely condensing the cytoplasm in their immediate neighbourhood. 
In corrosive sublimate preparations which have been carefully stained 
with Delafield’s or Ehrlich’s hematoxylin or with Meyer’s hemalum, 
the cytoplasm gives unmistakable evidence of the presence of chromatin 
diffused through it as well as localized at particular points. This diffuse 
distribution causes the whole cell to be deeply stained when one employs 
the ordinary staining reagents, in the concentrated form which is usual 
in the case of other cytological preparations. It is the most striking 
point that one finds when one for the first time makes preparations of 
yeast cells, and this being so it is surprising that little attention has been 
given to it in the literature of the subject. 
