THE ORGANIC CELL 
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1855 to 1858, came to the conclusion that cell-division proceeds 
from the centre to the periphery. Commencing in the nucleolus 
which divides, the process is continued in the nucleus, and 
afterwards is completed by the division of the cell-body and 
envelope. For nearly twenty years this was the accepted 
teaching regarding cell-division. In the year 1878 a set of 
most important discoveries were made, which showed clearly 
that cell-division was in very many cases a most complicated 
process, involving an extremely intricate change in the nucleus 
to which Schleicher gave the name of Karyokinesis. It must 
be remembered, however, that this complicated process is not 
absolutely universal, and that there is another simpler, though 
much rarer, method of division, corresponding to that described 
above by Remak, and which van Beneden characterised as 
fragmentation. 
To be brief, it may be stated that there are two recognised 
methods of cell-division for which Flemming proposed the 
terms direct and indirect division, terms still in use. Later 
Flemming proposed to substitute for these : — 
Amitosis, representing the direct method, and Mitosis, the 
indirect or Karyokinetic method. 
It has been demonstrated that the method of direct 
division is a very rare process, and occurs during the life history 
of cells which are undergoing degenerative changes, and are 
on the downward path tp disintegration. It appears to be a 
sign of degradation in specialised cells which are incapable of 
long-continued division. It is very characteristic of the cells 
forming temporary embryonic envelopes &c. In this form of 
cell-division the nucleus becomes divided into two portions, 
followed by a similar division of the cytoplasm. 
Indieect Division ok Mitosis 
In this description I shall take a type of Mitosis in which 
a persistent centrosome is present, as has been demonstrated 
in the division of the testis-cells. In a series of articles of this 
kind it would be superfluous, and possibly a little exhausting 
to the reader, to point out the variations in detail occurring 
in different animals and plants. There are many minute 
