ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
751 
BOTANY. 
A. GENERAL, including the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
Cl) Cell-structure and Protoplasm. 
Division of the Cell-nucleus.* — M. C. Decagny calls attention to the 
fact that at the moment when the nucleus is about to divide it is seen to 
swell considerably. This is due to the expulsion of albuminoid matters 
from the nucleole ; and these are then again expelled from the nucleus 
by diffusion through its membrane. It is the most diffusible matters 
that escape first into the cell, where they are immediately coagulated by 
contact with the cell-sap, and large vacuoles are formed around the nucleus ; 
these swell in the same way as the nucleus, for which they serve as 
appendages filled with the same albuminoid substances. These pro- 
cesses take place equally in Sjoirogijra (setiformis and jugalis) and in the 
endosperm of the lily. 
Constitution of the Cell.f — In a fresh contribution on this subject 
Dr. L. Buscalioni deals with the ovules of Veronica hedersefolia and of 
several species of Verbascum. In the ovule of Veronica he notices a 
remarkable difference in the structure of the micropylar and chalazal 
extremities of the embryo-sac. The structure and development of the 
ovule of Verbascum are described in great detail, and the observations 
lead to the following conclusions : — 
The structure of the protoplasm is reticulate. The filaments or 
meshes of the protoplasmic network are composed of microsomes and of 
a cementing substance, and are completely transformed into cellulose, 
while maintaining entirely their optical appearance. The thickening 
layers of the cell-wall are composed of cellulose and not of cutin. In 
the cellulose-filaments are two substances, the cement and the granules, 
of different physical and chemical constitution. The granules bear a 
remarkable resemblance to the so-called “ bacteroids ” of the root- 
tubercles of Leguminosee, and are probably identical with them. 
Mechanics of Growth of the Cell-wall4 — Herr A. Zimmermann 
publishes a contribution to the solution of the question whether the 
increase of surface of cell-walls is always due to turgor. Intercellular 
spaces he divides into two classes, according as the walls of the limiting 
cells bulge inwards or outwards. In the former case the growth of the cell 
may clearly be attributed to turgor ; the latter present greater difficulties. 
To this latter category belong the intercellular spaces in the parenchyme 
of Juncus. Here the branches of the stellate cells are formed by pro- 
trusion, and the phenomena are quite compatible with growth by turgor. 
But in the branched palisade-cells of the leaves of Pinus the process is 
different, and the folds grow centripetally towards the interior of the 
* Comptes Rendus, cxvi. (1893) pp. 1397-1400. 
f Malpighia, vii. (1893) pp. 105-62 (2 pis.). Cf. this Journal, ante, p. 57. 
X Beitr. z. Morph, u. Phys. d. Pflanzenzelle (Zimmermann) Heft 3, pp. 189-240 
(13 figs.). See Bot. Centralbh, lv. (1893) p. 105. 
