NOTE ON THE CYTOLOGY OF OALOTHRIX PUSOA. 627 
the destruction of the central body has not a merely mecha- 
nical cause. 
I vainly tried to make out the chemical nature of these 
hyaline granules. They are not identical with the “ cyano- 
phycinkornchen ” of the Glerman authors, nor do they con- 
sist of fat. They are only a little to be stained with eosine 
and carbolic fuchsin, they are dissolved in diluted acids and 
in pepsine, not in diluted alkalies. 
The changes in cell-structure in the microtome sections 
were controlled by the study of toto-stained preparations. 
After fixation the cells were placed on a cover-glass, and were 
stained and imbedded in the ordinary way. The normal 
central bodies had the same aspect as in the sections (PI. 32, 
fig. 10). The begitming of dissolution of the central body 
was also very clearly to be seen (PI. 32, fig. 12) in these pre- 
parations, also the cells with diffuse chromatin (PI. 32, fig. 11). 
Generally the distinction between the protoplasma of the 
central body and the surrounding parts was not very clearly 
to be seen. Except this point the toto-preparations had the 
same value as the sections. 
I will now shortly discuss the results of the observations 
described here. The normally built central body of Oalo- 
thrix fusca contains chromatin granules imbedded in the 
alveoli of the plasma of the central body (the “achromatic 
substratum”). The latter is easily differentiated from the 
cytoplasma ; the alveoli of the latter are the continuation of 
those of the aclu’omatic substratum. I think therefore with 
Guilliermondthat the central body of theCyanophycesemust be 
regarded as a primordial nucleus, the difference of cytoplasma 
and nuclear plasma already existing, but being not yet very 
distinctly marked. Under certain circumstances, unknown 
to me, the central body becomes at first irregularly shaped 
(in this stage the central body resembles strikingly the 
“ diffuse nuclei ” of Opalinopsis and Poettingeria), after 
which the difference between cytoplasma and nuclear plasma 
(s. achromatic substratum) disappears, and the chromatin 
granules ai’e spread throughout the whole cell. 
VOL. 54, PART 4. — NEW SERIES. 
44 
