200b
50h
40
30
3
20
I0r
2 o
0
40
30
20
0
240
160
801
0
'
4
'
t
'
12 '
16
1
Hours after division
FIG. 2. Total dry mass, u.v. absorption and Feulgen-stain measurements on monkey kidney
nuclei, plotted against the cell ages on a time-lapse film. In the uppermost diagram the
individual measurements have been averaged at intervals throughout interphase and the
results are plotted together: the numbers at the top of the figure indicate the numbers of cells
representing each point, x
x, Feulgen D N A curve; 0
0, dry mass
curve; + , u.v. absorption (total nucleic acid) points. The mean intermitotic time of the culture
was ofthe order of 17 h: the four cells at about 16 h having low Feulgen, u.v. absorption and
dry mass are clearly in a longer synthetic cycle than the other cells and have not been included
in the average measurements above nor has the tetraploid cell at 13*5 h. All the measurements are replotted in the correlation diagram in Fig. 4.
Nuclear dry mass Nuclear nucleic acid
Average dry mass
Average Feulgen
stain
Average nuclear nucleic
acid xl0"
l2
g