‘ Heterotypical Reduction ’ in Somatic Cells . 79 r 
found in the extreme tip of the root, as well as throughout periblem and 
plerome far back to the permanent tissue. Fewer of them, however, occur 
near the growing point than at a distance from it. 
4. After 65 hours subsequent groivth. 
At the end of 65 hours’ growth subsequent to experiment, there is 
no effect of the poison to be seen other than is shown in structural modifica¬ 
tions similar to those which have just been described. The tissue takes up 
the stain very well in external as well as internal cell rows, showing all 
details sharply defined. As to the above structural changes, the chief 
points in which they differ from those seen at the earlier stage are the 
following: The tetraploid cells, with their double-number diasters, dupli¬ 
cated equatorial plates, and large telophases, now lie rather further back in 
the tissue than at the preceding fixation, and they are if anything rather 
more abnormal in size. Many of them also contain as many as three nuclei, 
all of which may be seen in process of degeneration, staining diffusely and 
with fragmented nucleoli. Here and there, crushed between two large cells 
or wedged obliquely between several cells of peculiar shape, are masses 
of disintegrated chromatin, presumably showing where some cell has lapsed 
into degeneration. Far back from the growing point, in the permanent 
tissue, are to be seen long cells emptied of their contents and with two, 
or in some instances three, nuclei which have dropped against the cell wall 
and fallen into inactivity. 
5. After 70 hours ' 1 subsequent growth. 
After an interval of 70 hours subsequent to the experiment, again the 
same characteristics are to be observed. The tissue as a whole seems 
to have recovered its normal condition, all vacuolation of the cytoplasm, 
swelling of the cell walls, and diffuseness of staining having disappeared. 
But the above structural peculiarities still persist. These show, however, 
an increase in two slight but significant changes observed at the preceding 
fixation. In the first place the tetraploid cells have reached even more 
abnormal dimensions, catching the eye at once under a low power of 
magnification. And in the second place there is an increase in the pre¬ 
ponderance of the number of these cells found at a distance from the root- 
tip, over that found near the growing point. It should also be noted that 
the masses of disintegrated chromatin appear to be more numerous than at 
the preceding fixation. The nucleoli are still for the most part more broken 
up than is the case in normal tissue. 
6. After 85 hours of subsequent groivth. 
Roots examined after an interval of 85 hours show the same kind 
of features as those described at the preceding fixation, but the tetraploid 
3 H % 
