338 Mottier . — The Effect of 
somewhat distorted. A distortion of the figure is, however, 
not the rule in Tradescantia , but slight distortions may be 
often present which are invisible in the living cell. 
In Fig. 7 is shown a cell with dividing nucleus, in which 
the straight or slightly curved rod-shaped chromosomes have 
arrived at the poles. Each set of chromosomes is inclined 
slightly to the longitudinal axis of the spindle. Judging from 
this figure, it seems that the spindle-fibres extending from 
pole to pole offer some resistance to the weight of the chromo- 
somes of the one daughter-nucleus which tend to fall into the 
end of the cell upon those of the other daughter-nucleus. In 
no case observed were the chromosomes at one pole thrown 
over upon those at the other. The chromosomes (Fig. 7) did 
not orient themselves again so that their long axes might 
coincide with that of the cell, but formed at once the daughter- 
spirem by the union of their respective adjacent ends. It 
must not be forgotten, however, that only a few of the finer 
details of the karyokinetic figure can be seen in the living 
plant-cell even in the most favourable cases. The spindle- 
fibres in the cell shown in Fig. 7 could be seen only faintly, 
the displaced cytoplasm in which the karyokinetic figure lay 
rendering the view less clear than under ordinary conditions, 
so that a more accurate knowledge of detail must await 
investigation by the indirect method. The division-wall 
resulting from this division (Fig. 7) was only slightly oblique. 
Its formation, which was observed continually, took place in 
about the same time as in cells not exposed to centrifugal action. 
Fig. 9 a-g will serve to illustrate the process of cell-division 
immediately following a transverse displacement of the 
contents. The protoplasm capable of being moved by the 
centrifugal force was merely collected along one side of the cell, 
thus suffering displacement through a relatively short distance. 
When first observed the nucleus was in the anaphase (Fig. 9 a ). 
The cell- plate is soon laid down within the connecting fibres 
and in contact with the cell- wall upon one side (Fig. 9 b). 
The connecting fibres gradually bulge out at the equator, 
forming the familiar barrel-shaped system. The bending out 
