1921] MEIER—ROOT TIP 133 
KireE states that when such a protoplast was cut into, the pieces 
retained their shape definitely and behaved distinctly as a gel. 
In the region of rapid elongation in both cortex and central 
cylinder, 3-5 mm. from the cap, the cytological picture reveals 
little effect compared with the extreme tip. The cytoplasm shows 
no migration whatever, although it is more coarsely granular than 
that of the controls. The nucleolus retains its form and position, 
while the chromatin is aggregated in a crescent-shaped mass against 
the nuclear membrane toward the positive electrode in a majority 
of cells, in a few toward the negative electrode. In some cases, 
however, the entire nuclear material is displaced within the cavity 
(fig. 6), and in a few cases even the entire nucleus lies in a dense 
mass against the wall toward the positive electrode, a phenomenon 
not met with at this exposure in cells nearer the cap. Shrinkage is 
quite evident in the region of rapid elongation. 
The root cap rarely shows any displacement of either cytoplasm 
or nucleus, doubtless largely due to the fact that the moist kaolin 
of the electrode is a better conductor than the root, and so very 
little current passes through the cap. 
The first noticeable cytological effect of the current is produced 
on exposure of approximately one-tenth of the time required to 
produce death, and the first visible reactions occur in the cortical 
region about 1 mm. above the cap. Such cells show large vacuoles 
in the end toward the negative electrode, and the cytoplasm appears 
slightly more granular than in the controls. The chromatin at this 
stage is beginning to migrate toward the positive electrode. The 
nucleolus lies in its normal position, but soon after one-tenth of 
time exposure begins to show the flattening previously described. 
At this stage the region above the first millimeter shows nothing 
abnormal, neither do the cells immediately behind the central 
portion of the root cap. The effect of the current is progressive 
and the results are cumulative. At one-half of the time for death 
point, the nucleolus flattens and the cytoplasm definitely begins 
to migrate. With an exposure of three-fourths of the time for 
death the nucleolus and chromatin have migrated toward the 
positive electrode, the cytoplasm being very coarsely granular and 
exhibiting a greater amount of migration than in the previous 
