Overton—On the Boot Tips of Podophyllum Peltatum. 277 
Sections were cut from three to eight microns thick, and the 
preparations were stained with Flemming’s triple combination or 
by either Heidenhain’s or Benda’s haematoxylin methods. Care¬ 
ful comparisons were always made between preparations stained 
by the various methods. 
Observations 
I shall describe the structure of the chromosomes during mi¬ 
tosis in the root tips of Podophyllum peltatum L. beginning with 
the equatorial plate stage, and follow the changes which occur 
during the reconstruction of the daughter nuclei, and also the 
structure and organization of the resting nucleus in so far as I 
have been able to determine and interpret the phenomena. 
Metaphases and Anaphases 
Figure 1 shows a section of an equatorial plate in lateral view 
in which five entire chromosomes are present and a portion of a 
sixth, whose remaining part has been cut away. In general the 
chromosomes lie in a plane nearly perpendicular to the long axis 
of the spindle. It can be seen that in some cases a bundle of 
fibers is attached at about the middle of each chromosome while 
in other cases the attachment is at or nearer one end. Although 
the chromosomes lie usually with one end in or near the equato¬ 
rial plane, their free ends may often assume various other posi¬ 
tions with reference to the axis of the spindle. Examining the 
chromosomes shown in figure 1 more in detail one can see that 
they are not homogeneous in structure, as they have been de¬ 
scribed and figured by most observers. In each chromosome may 
be seen lighter and darker portions. In the chromosomes in the 
center of this figure a double row of bodies is distinctly visible, 
making this chromosome appear longitudinally split. There ap¬ 
pear to be two stainable substances present in these chromosomes, 
a less stainable supporting homogeneous trama in which granular 
portions are imbedded. The trama appears between the indi¬ 
vidual granules and between the two rows of granulas as a less 
deeply stained streak. The darkly staining bodies in each row 
lie opposite each other. "With the triple combination the bodies 
stain bluish red or purple like chromatin, while the substratum 
stains an orange red like linin. These chromatic bodies are not 
