200 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
in various growing tissues. In the root-tip of Hyacinthus orientalis he 
observed a periodicity in the divisions, principally in the periblem. At 
a later stage, especially in the cells of the root-cap, he states that the 
amount of nuclein diminishes with the increasing age of the cell ; the 
framework is composed of thick threads and wide meshes, the nuclear 
membrane becomes distinct, the nuclei acquire the power of assuming 
various forms, and the nucleoles become scattered and decrease in mass, 
the entire mass of the nucleus also diminishing. Similar appearances 
were seen also in the formation of raphid-cells and of vessels, except that 
the nucleoles in these cases increase in size. 
At the commencement of the nuclear division in the root of the 
hyacinth, the nucleus is surrounded by a hyaline layer of kinoplasm ; 
this soon becomes concentrated in the form of two opposite caps, from 
which the achromatic nuclear spindle is formed before the absorption of 
the membrane. The author could discover no centrosomes ; the number 
of chromosomes he made out to be twenty-four. Analogous results were 
obtained in other similar tissues and in ferns. 
In the spore-mother-cells of Psilotum the author detected, before the 
commencement of the first division, a delicately filamentous structure 
of the chromatin, which he calls the dolichonema- stage. The nucleus 
appears to become suddenly filled by an enormous number of extremely 
delicate serpentine threads, which subsequently become granular, lose 
their individuality, and are transformed into spirema-filaments. 
As a fixing material for the meristem of roots, Rosen employs a 
mixture of 10 gr. sublimate, 300 gr. distilled water, and 3 gr. glacial 
acetic acid ; for ferns a mixture of 6 parts alcohol, 1 part glacial acetic 
acid, and 2 parts chloroform. As staining reagents, he uses iodine- 
green-fuchsin and Heidenhain’s hsematoxylin-iron-alum in combination 
with Bordeaux R., or Rubin S. 
Mitosis and Fragmentation.* — Dr. Hegler insists on the point that 
mitosis and fragmentation are not identical. Only in cells which result 
from mitosis is the entire mass inherited ; cells formed by fragmentation 
cannot produce new individuals, although they frequently display an 
increased growth in length. New individuals may arise from the cells 
of the nodes of Tradescantia, the nuclei of which divide by mitosis; 
not from those of the internodes, in which the nuclei divide by frag- 
mentation. There are, however, intermediate processes between mitosis 
and fragmentation. By the help of special methods of preparation, the 
author was able to demonstrate karyokinetic division of the nucleus in 
several Schizophycem, in all its stages, aster, diaster, &c., as also the 
presence of a nucleus in the spores of bacteria. 
Division of the Nucleus in Spirogyra.t — M. C. Decagny has 
followed out the stages of nuclear division in Spirogyra anterior to 
the disappearance of the nuclear membrane. These may be arranged 
under two phases. 
In the first phase the nucleus swells, forming in its caryoplasm a 
certain quantity of protoplasmic substances which pass gradually into 
* Ber. Yersamml. Beutsch. Naturf. u. Aerzte, 1895. See Bot. Centralbl., lxiv 
(1895) p. 203. 
t Bull. Soc. Bot. France, xlii. (1895) pp. 319-26. Cf. this Journal, 1895, p. 329. 
