131 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
BOTANY. 
A. GENERAL, including tlie Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-Structure and Protoplasm. 
Structure and Physiology of the Cell.* — According to researches 
made on vegetable cells ( Anacharis , Hydrodictyon ) by M. M. Tswetfc, 
strongly plasmolytic solutions determine the accumulation in the proto- 
plasts of the polioplasm (the circulating portion of the cytoplasm) and of 
the plastids included in it. To this process he applies the term plas - 
mosynagy. It is a phenomenon of irritability, a vital reaction of the 
protoplasm to plasmolytic irritation. 
The chloroplasts ( Elodea ) are composed of a network of dense re- 
fringent substance ( chlorojplastin ), the sole support of the chlorophyll, 
and of an uncoloured interstitial substance ( metaxin ) ; both substances are 
of a proteid character. Tlie chloroplasts have no differentiated proto- 
plasmic membrane resembling that of the vacuoles. Their chemical 
composition varies with the season of the year. 
Non-Nucleated Cells.j — Herr J. J. Gerassimoff states that cells 
without a nucleus can be obtained, not only, as previously indicated, by 
exposure to a low temperature during the process of cell-division, but 
also by the action of certain reagents, as chloral hydrate, ether, or 
chloroform. The daughter-cell which contains no nucleus exists only 
for a short time, but contains normal chlorophyll-bands of a somewhat 
darker colour, and may form starch in the light. These phenomena 
had been observed chiefly in Spirogyra, but occur also in Zygnema. 
Influence of Traction and Pressure on the direction of Partition- 
Walls. :j; — As the result of experiments on potatoes and on tap-roots, Herr 
L. Kny confirms, as a general rule, Hofmeister’s law that the position 
of newly formed septa is determined by the preceding growth, the 
dividing-wall standing at right-angles to the direction of the strongest 
previous growth of the cell. This is, however, modified by the law 
that the orientation of the nuclear figure, and consequently that of the 
septum, may be affected by giving an arbitrary direction, through traction 
or pressure, to the preceding most intense growth. 
(2) Other Cell-contents (including Secretions). 
Formation of Secretions. § — According to Prof. A. Tschirch, resin, 
oil, and other secretions are never formed within the cell-membrane, but 
in a special layer known as the resinogenous layer. The septa which 
occur in the vittse of Umbelliferse are remains of this layer. The sub- 
stance of the layer, which the author calls vittin , is of a pectinaceous 
* Arch. Sci. Phys. et Nat., ci. (1896) pp. 228-60, 467-86, 565-74 (1 pi.). 
t ‘ Ueber ein Verfaliren kernlose Zellen zu erkalten,’ Moskau, 1896, 4 pp. 
X Ber. Deutsch. Bot. Gesell., xiv. (1896) pp. 378-91 (2 figs.). 
§ SB. 68 Yers. Deutscker Naturf. u. Aerzte. See Bot. Centralbl., Ixviii. (1896) 
p. 212. 
