Overton—On the Boot Tips of Podophyllum Peltatum. 287 
Interphase 
As Sharp (’13) points out, we are indebted to Lundegard 
(’125) for this term, which is applied to the period in the nuclear 
history between two successive intervals of division in tissues 
composed of rapidly dividing cells. I am in agreement with these 
two workers that the transformation of the telophasic chromosomes 
does not in general proceed as far in such nuclei as in older tis¬ 
sues, in which the divisions proceed more slowly. Figures 11 and 
12 represent stages in which many nuclei are found to pass the 
interphase. I have been unable in the root tips of Podophyllum 
to find nuclei with a more uniform reticulum than is shown in 
figures 9 and 10. In this stage one or two nucleoli are present, 
as shown in figure 9. Eeticulation may proceed further in older 
portions of the root, as is noted by Sharp (’13). Although larger 
chromatic masses may be present, I have been unable to distinguish 
any distinct caryotin clumps or karyosomes as described by Lun¬ 
degard (’10 a, ’12 b) for Vicia, and have never found these karyo¬ 
somes split as described by him. 
The Early prophases 
The resting nucleus, as I have described it, consists of elemen¬ 
tary reticula, which in Podophyllum may often be recognized as 
distinctly independent alveolar-reticulate bands or areas, while in 
other cases these areas are not distinguishable (compare figs. 9 and 
11) . During the prophases a reconstruction or condensation oc¬ 
curs to form the chromosomes of division. During the very early 
prophases the first evidence of a preparation for division is notice¬ 
able in a somewhat greater affinity of these bands for stains, the 
reticulum becoming more dense and chromatic in appearance es¬ 
pecially along the bands. Each band or chromosome becomes 
more distinct, resembling those of the reconstruction stages (fig. 
12) , The vacuoles become fewer and the chromatic portions 
larger and closer together. The process continues until the con¬ 
densing alveolar-reticulate portions become quite distinct, with 
clear areas between, as shown in figure 13. The chromosomes thus 
condensing appear as rather definite bands, each band represent¬ 
ing a chromosome of the telophase. 
As pointed out above, the resting reticulum may be a rather 
uniform network (fig. 9), or the chromosomes may appear less 
