444 TRANSACTIONS OF THE CANADIAN INSTITUTE, [VoL. VI. 
One of these two, related to plastin in its characters, was always found 
to be present; the other, denominated the “ central substance” (Central 
Substanz), which might be absent, was found to be similar to the nuclein 
of higher organisms in many respects. The substance of the nucleoli- 
like elements was not found to differ from that of the nucleoli of higher 
plants. 
Zacharias discussed the question whether the central colourless body 
represents a nucleus, contrasting it with the nuclei of higher forms of 
vegetable life, and pointing out that in the Cyanophycee nuclein may 
be present in some cells of a thread, but wholly absent in others, a con- 
dition not observed in the tissues of more highly organized vegetable 
forms. Nuclein was wholly absent in the dividing cells of Cyano- 
phycez, while division in the cells of higher organisms is always pre- 
ceded by an increase in the quantity of chromatin or nuclein. On 
account of such contrasts Zacharias regarded it as uncertain whether 
the “central substance” of the Cyanophycez represents the nuclein of 
other organisms, and he concluded that the central body is different 
in all its relations from a nucleus. The absence of a nucleus is, he 
believes, associated in some way with the absence of a sexual process. 
Bitschli,' in his studies on the structure of Bacteria and Cyano- 
phycez, came to the conclusion that in both the same type of structure 
prevails. He found in the cells of the Cyanophycee a_ peripheral 
coloured zone of cytoplasm which stains feebly with hematoxylin, 
enclosing a colourless “central body” which takes the haematoxylin 
stain more strongly. The two structures are vesiculated, that is, pro- 
vided with a honeycomb-like structure (Wabenstruktur). In the cyto- 
plasm hematoxylin reveals, by the red colour which it gives them, a 
number of granules, termed by Biitschli the “red” granules, which are 
situated in the nodal points of the vesicles, and are more abundant and 
larger at the periphery of the central body than elsewhere. These are 
not to be found after the cells have been treated with hydrochloric acid 
and pepsin, but he attributes their disappearance to the digesting re- 
agent, having deprived them of the power of taking up dyes, since they 
readily lose their power of staining when they are fixed with osmic acid, 
corrosive sublimate, or with the picro-sulphuric or chrom-osmic-acetic 
mixtures. He is inclined to regard them as composed of a substance 
like chromatin in many respects. Other granules of a different nature 
were found in the peripheral cytoplasm, and more particularly near the 
transverse walls in Osczllar¢a, which exhibited an affinity for eosin, but 
1 ‘*‘ Ueber den Bau der Bacterien und verwandter Organismen,” Leipzig, 1890. 
