334 Mot tier . — Effect of 
tribution was complete, there was nothing to indicate in any 
way that either bands or nucleus had experienced any change 
in position in the cell. The nucleus did not always resume 
an exactly central position in the cell ; sometimes it would 
not quite reach the centre, or it might pass a short distance 
beyond it. 
As in Cladophora. cells sometimes divided before a com- 
plete redistribution of the contents was accomplished, when 
the daughter-cells varied greatly in length, being to each 
other as 1 : 3 . In the shorter cell the chlorophyll-bands 
necessarily remained crowded closely together, giving the cell 
a dark-green colour ; in the longer, the relatively shorter pieces 
of bands stretched themselves the entire length of the cell, 
making not more than one and a half transverse turns. The 
nuclei always took up a central position in their respective 
cells. 
Centrifugal force acting transversely upon the cells of 
Spirogyra often seriously affected their vitality, in fact killing 
many outright. As a rule a longer time was found necessary 
to effect a complete transverse displacement of the chlorophyll- 
bands. In large cells whose several bands wound at a sharp 
angle, these are usually broken at the side of the cell from 
which they are removed. In passing over to the opposite or 
‘ lower side 1 ’ of the cell, one free end of each severed portion 
moves along in the primordial utricle upon one side parallel 
to the direction of centrifugal force, and the other upon the 
other side. Everything seemed to indicate that the ends 
arising from the severing of the bands did not move through 
the vacuole. In rather long and slender cells, however, with 
only few bands making long turns, the bands are not severed, 
and it seems that the displaced portion passes directly through 
the central cavity or vacuole. 
Whenever the bands were broken at several points, the cell 
was so injured that death resulted soon after centrifugal 
action. It often happened that only a partial displacement 
1 By ‘ lower side ’ or ‘ lower end ’ is meant that against which or into which the 
contents are accumulated by the centrifugal force. 
