636 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
BOTANY. 
A. GENERAL, including the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-Structure and Protoplasm. ’ 
Form of the Cell-nucleus.* — In a paper on the Physiology of the 
Cell-nucleus, Dr. F. G. Kohl set3 down the normal form of the nucleus 
in young protoplasmic cells as spherical or elliptical. But subsequently 
its form may undergo very great change ; as in the elongated vermiform 
nuclei of the parenchymatous cells in the vascular bundles of Allium 
Porrum , the cells of the hairs of Tradescantia, &c., where the length of 
the nucleus may be fifty times its breadth. In the endosperm-cells 
of Zea Mays the nuclei are peculiar branched filiform bodies which fill 
up the spaces between the starch grains. In the epidermal cells of 
Hyacinthus orientalis the nuclei are pointed at both ends, as also are 
those of the epidermal cells of the leaf of Ornithogalum . umbellatum , 
and those of the hairs on the leaf-stalk of Pelargonium zonale. In cells 
with living protoplasm endowed with motility the author was, in some 
cases, able to see a slow change of form, when the outline was observed 
at intervals of 20, 30, or 40 minutes. Amoeboid motions, similar to those 
of the nucleus of animal cells, were also observed in some instances, 
connected probably with the absorption of nutriment by the nucleus. 
This had apparently not been observed before in vegetable cells enclosed 
in a cell-wall. 
Streaming of Protoplasm. f — From observations made on the hairs 
on the flower of the common gourd, Herr M. Heidenhain contests the 
ordinary statement that solid particles (granules) are passively carried 
along in protoplasm-currents. The “ streaming ” of the granules is a 
phenomenon quite distinct from the local movement of masses of proto- 
plasm, though the two kinds of motion may concur. The movement 
of the granules may, however, take place equally when the mass of 
protoplasm is at rest. 
Chromatolysis of the Nucleus.^ — From a study chiefly of the 
muciferous idioblasts of Opuniia , Dr. B. Longo comes to conclusions 
in several points opposed to those of Cavara. He maintains that the 
phenomenon of chromatolysis does not occur in normal nuclei ; that 
the nucleoles are composed of a single substance, and not of a central 
substance (plastin of Zacharias, pyrenin of Schwartz, representing, 
according to Cavara, the nucleole properly so called), and of a peripheral 
substance representing the chromatin ; that the “ nucleole properly so 
called ” of Cavara is nothing but a vacuole ; that the nucleoles are per- 
fectly homogeneous, vacuolated, but not alveolated. He concludes that 
at present we know nothing of the true function of the nucleoles. 
* SB. 69. Versam. Deutsch. Naturf. u. Aerzte, Braunschweig, 1897. See Bot. 
Centralbl., lxxii. (1897) p. 168. 
t SB. Phys.-ined. Gesell. Wurzburg, 1897 (1898) pp. 116-39. 
X Atti r. Accad. Lincei, vii. (1898) pp. 282-90. Cf. this Journal, ante, p. 549. 
