580 REPORT—1905. 
Macallum, do not contain potassium. These qualities are characteristic of nuclein, 
and there can be, I think, no reasonable doubt that these granules are comparable 
to the chromatin of a true nucleus. 
In favourable objects it can be seen that these chromatin granules are asso- 
ciated in rows, and are sometimes so close together as to give the impression of 
granular threads, united in such a way as to form a granular network. — 
During the division of the cell the central body becomes elongated, and this 
granular network in consequence becomes pulled out in such a way as to give the 
appearance of a number of threads lying side by side, and, as Olive has justly 
pointed out, this gives the impression in deeply stained cells of a number of 
separate chromosomes lying side by side. It does, in fact, resemble, at a super- 
ficial glance, a stage in the karyokinetic division of a nucleus, Careful examina- 
tion, however, reveals the original reticulate structure, and the subsequent stages 
of division show that this central body divides by constriction only, and presents 
none of the characteristics of a true mitosis; and, contrary to the views of Kohl and 
Olive, nothing in the nature of a true spindle figure is formed. 
In addition to the true chromatin granules there are present at the periphery 
of the central body, and in close contact, therefore, with the chlorophyll-containing 
portion of the cell, other granules of a different, more refractive appearance, the 
true nature of which is not known. These are the red granules of Butschli; and 
from the fact that they give similar reactions towards reagents as the chromatin 
were regarded by him as the true chromatin granules. ‘Their true function is 
unknown, and they do not occur in all cells even of the same filament. 
There can be no doubt that the interpretation of the structures we are here 
dealing with is very difficult, but I do not understand how the conclusions reached 
by Fischer in his most recent paper, Die Zelle der Cyanophycez, ‘ Bot. Zeit.,’ 
1905, can have been arrived at. If I interpret his conclusions correctly, he con- 
siders that the chromosome-like granules in the central bedy of Oserllarza princeps 
and O. limosa are composed of glycogen. In most other species glycogen is only 
found in the chromatophore, but the glycogen may pass from the chromatophore 
into the central body and become changed into another carbohydrate, which he 
calls ‘anabeenin.’ This substance arranges itself either in the form of granules or 
of pseudo-mitotic skeins and similar masses. . The nuclear-like figures which have 
been described by various observers are composed of anabzenin, and this substance 
in cell division undergoes a pseudo-mitotic division or ‘carbohydrate mitosis.’ 
It is, perhaps, a sufficient criticism of these conclusions to point out that the 
micro-chemical characteristics of these central granules are certainly not those of 
carbohydrates. 
From a consideration of the facts we at present know concerning the central 
body we cannot, I think, escape the conclusion that it is of the nature of a nucleus, 
but one of a simple or rudimentary type. It is not sharply delimited from the 
surrounding cytoplasm, although it sometimes appears as a vacuolar cavity in the 
centre of the cell, with a vacuolar membrane around it. It seems to me that we 
might very well regard it simply as a specialised region of the cytoplasm which 
possesses & pronounced vacuolation associated with granules of chromatin or with 
a chromatin network. 
The Function of the Nucleus of the Cyanophycee. 
The nucleus of the Cyanophycee is very large, much larger proportionally than 
the nuclei of the higher alge. It gives also a proportionally stronger reaction for 
phosphorus. Some observers have considered the large size and prominence of the 
central body as an argument against its nuclear nature. In the alge the nuclei 
are much smaller in proportion to the cell, and in many forms are very difficult to 
make out. On the other hand the pyrenoids which are present in the cells of 
algse stain more deeply in the nuclear stains, and give a much stronger reaction 
for phosphorus than the nuclei. In Prassiola parietina the pyrenoid is in the 
centre of the cell, and both in the living condition and in stained preparations is 
much more prominent than the slightly stained nucleus on one side of it. So, also, 
