ZOOLOGY AND EOT AN ST. MICROSCOPY, ETC. 
581 
BOTANY. 
A. GENERAL, including* the Anatomy and Physiolog*y 
of the Phanerogamia. 
a. Anatomy. 
CD Cell-structure and Protoplasm. 
Centrospheres of the Nucleus and Size of Cells.* — From the 
observation of swarmspores, gametes, and antherozoids, Prof. E. Stras- 
burger concludes that in the cytoplasm two constituents are contrasted 
in their activity. To one of these, the kinoplasm, the radiations round 
the centrospheres, the spindle-fibres, and the combining filaments (at 
least in vegetable cells), owe their origin ; and it is this which deter- 
mines the centrospheres of the kinetic centres in the cytoplasm. The 
other constituent, especially its granular portion, is chiefly service- 
able in the processes of nutrition; while its peripheral portion acts as 
a specific receiver of irritation ; this constituent is the tropkoplasm. 
Nuclear division takes place under the control of the kinetic centres, 
the irritation-impacts which proceed from them passing through the 
kinoplasm. 
A specially good example of the various processes is afforded by the 
internodal cells of CJicira. While they increase in size the nucleus 
breaks up into unequal fragments, and the quantity of cytoplasm 
increases more than a thousandfold ; the nuclei increase proportionally 
in number, because they are necessary for the formation of this enormous 
mass of cytoplasm. As far as has been observed in the vegetable king- 
dom, the centrospheres always lie outside the nucleus, and the whole 
mass of the nuclear spindle is formed of a single substance which occurs 
outside the nucleus in the cytoplasm. Every nucleus of a typical vege- 
table cell is accompanied by its centrospheres, and by so much kinoplasm 
as is necessary for its division, and, in the case of uninucleated cells, for 
the division of the cell. They form a kinetic unit, an energid in Sachs’s 
sense. In the Algae and Fungi, the trophoplasm alone takes part in 
cell-division. It is in the Mosses that the kinoplasm first begins to 
have a share in the process. 
Prof. Strasburger gives a large number of measurements of embryonal 
cells and of nuclei in vegetable tissues. The variations are very great ; 
in the former case between 0 • 024 and 0 • 005 mm. ; in the latter between 
0-016 and 0*003 mm. The average relation between the size of the 
nucleus and that of the embryonal cell is nearly as 2 to 3. 
Centrospheres in the Spores of Pellia.t — Prof. J. B. Farmer and 
Mr. J. Reeves find the spores of Pellia epipliylla (Hepaticas) a remark- 
ably good object for observing the part played by the centrospheres in 
the division of the nucleus. The best results were obtained with the 
following double stains used successively gentian-violet and orange G, 
gentian-violet and eosin, anilin-blue and acid fuchsin. 
When nuclear division is about to take place, two minute centro- 
* ‘ Ueb. d. Wirkungssphare der Kerne u. d. Zellgrosse,’ 28 pp., Jena, 1893. 
f Ann. Bot., viii. (1894) pp. 219-24 (1 pi.). 
