492 TRANSACTIONS OF THE CANADIAN INSTITUTE, [VoL. VI. 
In the cytoplasm as Errera' has shown, may be found glycogen, and 
it occurs in abundance in the cells of the later stages of fermentation. 
When iodine solution is applied to the cells from Pasteur solutions in the 
first nine hours after fermentation begins, very rarely only does it show 
the presence of glycogen, and then only in the form of minute granules. 
The slight brown tint which the cytoplasm in general at this time gives 
is due to the absorption of iodine by the cytoplasmic ehromatin, and is 
not due to dissolved glycogen. In cells of from ten to thirteen hours of 
cultivation in Pasteur solutions the glycogen occurs in small masses in 
the cell. These masses, of which there is usually one to each cell, vary 
in size, and are more or less irregular in outline and placed adjacent to 
the cell membrane. In later stages the glycogenic mass may be so 
large as to occupy the greater part of the cell. 
IV.—THE CHROMATIN-HOLDING STRUCTURES. 
In yeast cells which have been hardened in Flemming’s fluid or in 
corrosive sublimate solutions, and stained with very dilute solutions of 
Ehrlich’s or Delafield’s haematoxylin applied for from sixteen to twenty 
hours, one finds, as already pointed out, a slight colour, due to the 
presence of chromatin in the cytoplasm generally, and a very deep stain 
at one or more points in the cell. The latter may also be demonstrated 
by employing the iron-alum hematoxylin method for staining, but as it 
is not selective its action is less clearly indicative of the presence of 
chromatin, or of substances allied to chromatin, than that of the staining 
reagents mentioned. The diffuse stain which is given to the cytoplasm 
may serve to obscure the presence of a structure or structures which may 
be present. 
One frequent type of this structure is, ordinarily,a spherical mass like 
that represented in Figs. 36, 37, and 38, and, as in these cases, varying 
somewhat in size. This body, which I may term, for the sake of brevity, 
the corpuscle, is, in the great majority of cells, homogeneous and dense, 
and it stains much more deeply than the cytoplasm generally. It is 
not, however, always present, for it appears to be absent in cells in the 
different stages of fermentation, and no method of hardening and 
staining the cells will demonstrate its presence in all. This has been 
admitted by Bouin and Buscalioni. The former observer tried, by 
deeply restaining cells which at first appeared to be free from 
corpuscles, to bring out the presence of the latter, but succeeded only in 
1 Report British Association, Bristol Meeting, 1898, p, 1068. 
= f > 4 
