1904 | MERRIMAN: VEGETATIVE CELL DIVISION Ig!I 
This condition is especially to be observed in a few of the strands 
which are more favorably placed near the periphery. Fig. 3 
represents a similar cell cut lengthwise. As the nucleus enlarges 
still more, these double strands become more evident and regular 
in their arrangement, until we have the condition shown in the 
two periblem cells (fig. g). Here the strands pass around the 
‘inner surface of the nucleus in what appears to be a more or less 
regular and continuous spiral, while the nucleolus still holds its 
central position within. 
While bridges of the linin substance appear at first sight to 
connect the granules in pairs only, it is possible that the condi- 
tions are more complicated even at this stage, and that the chro- 
matic thread which seems to be composed of only two parallel 
threads is in reality made up of four such parts. Such quadri- 
partite thread with chromatic granules regularly arranged might 
give the appearance of being only bipartite, owing to the fact 
that, when viewed in certain directions obliquely to the axis of 
the thread, the pairs of granules in the distant half might appear 
to alternate with those of the nearer half. 
In Allium tips treated with Flemming fixative (weaker solu- 
tion), and not overstained by the iron alum haematoxylin 
method, the linin connecting the granules is less conspicuous. 
The granules, although they can still be traced as lying in 
Strands, are more isolated, and thus separated are seen to lie, not 
in groups of two, but in groups of four, The stages shown in 
Jigs. 5 and 6 (Flemming fixative) are directly comparable with 
the stage in fig. g (chrom-acetic fixative). The cell shown in 
Jig. 5 is a somewhat later stage of a periblem cell treated with 
Flemming fixative, while figs. 7 and & show later stages from 
tips similarly treated. The effect of the osmic acid in combina- 
tion with the chrom-acetic then, as seen by these figures, is to 
bring out with greater distinctness the arrangement of the gran- 
ules into tetrads. The linin can be distinguished in the cells 
thus treated, but it is more obscure than in the cells treated with 
chrom-acetic alone. 
It would be natural, from our preconceived ideas of the indi- 
viduality of the chromatin granules and of the necessity of an 
