932 General Notes. 
ZOOLOGY. 
CeLL-Drviston.—The following abstract of recent researches on 
cell-division is taken from the Journal of the Royal Microscopical 
Society.—Herr T. Boveri believes that the course of karyokinetic 
division may be generally described in the following terms :—The 
chromatic nuclear material becomes collected together with a 
definite number of isolated pieces of a form characteristic of the 
kind of cell—the chromatic elements; an achromatic filamentar 
figure is formed in the two poles, either from the substance of the 
nucleus or from that of the cell. The chromatic elements, so far 
as their number, form and size allow it, are deposited in the equa- 
torial plane of the achromatic figure ; the chromatic elements divide 
into two halves, one of which makes its way toward either pole; 
the daughter elements break up in the framework of the new 
nuclei. 
ments of the next spindle. 
n the germinal vesicle of the ovum of Ascaris megalocephala 
(Carnoy’s type), two independent portions of chromatin are found 
in the earliest known stage. Though nothing is certainly known 
of their mode of formation, it may be assumed that they are derived 
from a typical nuclear framework. This conversion, however, of 
the reticulum into the chromatic elements, which in other cells 
and in some ova (A. lumbricoides) directly precedes division, appears, 
in most eggs, to take a long time. e important difference in the 
eges of the type of Van Beneden is that there is but one chromatic 
element ; this seems to be unique. 
indication of the achromatic figures of division. The most striking 
of these cases has been lately described by Flemming. Similar 
phenomena have been observed by the author in the eggs ° 
Ascaris. n the germinal vesicle of Ascaris lumbricoides the 
