N. H. SWELLENGREBEL 
469 
from the centre to the periphery (and vice versa). If it is assembled in the 
centre, a “karyosome” seems to be present (not only stained but also 
in the “standard preparations”), but if the chromatin goes to the 
periphery the “karyosome” disappears. Hartmann would perhaps 
interpret this phenomenon as an evidence of the cyclic properties of the 
karyosome, but I doubt whether this view is quite correct. 
In preparations fixed with Flemming’s fluid and stained with 
iron-hematoxylin, nuclei may be seen of the shape drawn in fig. 9. 
The nucleus has undergone considerable shrinkage, two chromatic 
granules fill up the equatorial region and two others are situated at 
the poles of the spindle-shaped nucleus. Similar structures were 
sometimes interpreted as mitotic division. These nuclei are only to 
be found after wet fixation (especially Flemming’s), so I think these 
figures are artefacts produced by the considerable shrinkage sometimes 
following upon this mode of fixation. 
It may be noted that in studying the structure of the nucleus and 
the blepharoplast with the help of Giemsa’s stain it is necessary not to 
stain too long. In many cases the staining is just suited for the nucleus, 
at a moment when the flagellum is not yet stained. 
(c) Division of the blepharoplast. (Diagram IX.) The division 
begins with the augmentation of volume of the achromatic substance 
(fig. 1 a). Then the whole blepharoplast is elongated (fig. 1 h), the 
Diagram IX, 
Figs. 1—3. Stages of the division of the blepharoplast. 
chromatic substance becomes dumb-bell shaped (fig. 1 e) and presently 
is separated into two parts (fig. 1 d). The achromatic substance now 
becomes very much elongated (fig. 2) forming a regular “centrodesmosis.” 
At last it is broken and the two small daughter-blepharoplasts are formed 
each with their chromatic and achromatic components. Sometimes the 
chromatic portion is divided in three parts (Diagram VIII, fig. 8) but 
