Olive, Mitotic di Vision of tlie nuclei of tlie Cyanoßliyceae. 1 ( 
(97) and Massart (02). Among those who have asserted that 
it is a nucleus, which, moreover, divides mitotically, are Scott 
(87), Bütsclili (02), Hegter (01) and Kohl (03). Wäger (03) 
believes that tlie central body divides by direct division; while 
Ernst (89) and Znkal (94) think that each of tlie many slime 
globules represents a nncleus, which divides by simple frag- 
mentation. 
The theories of Hieronymus (92), Znkal (94) and 
Chodat (94) are historically interesting and deserve special 
notice. Chodat thought that the central portion of the proto- 
plasm of tlie cyanopliyceous cell became vacuolated, or emnlsified, 
and that this appearance, together with the granulär contents 
of the vacuoles — the cyanopliycin granules, tlie slime globules, 
and the „soluble starch“ — caused the differentation known as 
the central body. Zukal and Hieronymus have theories 
which present one point of resemblance to each other. Zukal 
regarded the slime globules as the true nuclei, which, according 
to him, divide, form membranes about themselves, and thus re- 
present many „naked cells“ within the one cyanopliyceous cell. 
These nuclei, he says, may be formed in two ways: they are 
either cut off from the central body or eise they are produced 
from cyanophycin granules, which may be slowly changed into 
nuclei. And most curious theory of all-the central body is itself 
formed from the fusion of the cyanophycin granules and slime 
globules! Thus the central body 'may on the one hand cut off 
portions of itself to form cyanophycin granules and slime glo¬ 
bules, and on the other hand, it may be itself reformed by 
fusion of fliese two kinds of granulär substances! 
Hieronymus calls the central body an „open cell nucleus“, 
as distinguished from the „closed“ nucleus of higher organisms. 
This really means nothing more, in my interpretation, than that 
the central body is devoid of the nuclear membrane which is 
characteristic of the resting nuclei of higher plants. Hiero¬ 
nymus says, moreover, that the cyanophycin granules (he probably 
means here rather the slime globules, or „red granules“) are pushed 
out from the nucleus, and that they represent the chromatin gran¬ 
ules. Herein his theory bears some resemblance to that of 
Zukal. 
We are now prepared to examine more closely the central 
body, which has occasioned so much confusion and difference of 
opinion. One of the main arguments of Fischer against the 
nuclear nature of this body is the fact that it occupies such a large 
proportion of tlie space in the cell. It indeed strikes one at 
first examination that the central body is comparatively large 
and that the cytoplasmic portion of the cell is relative)y small, 
as is well shown by longitudinal sections of Oscillatoria (figs. 7 
to 10, 14, 17). 
In filaments examined as a whole as well as in sections too 
deeply colored, the central portion usually stains as is shown in 
Beihefte Bot. Centralbh Bd. XVTTT. Abt.-I. Heft 1. ^ 
