The radicles did not keep healthy
for long. The result was that 6 were plainly and 2 doubtfully deflected
from the attached objects and the perpendicular; 11 not being affected. The
evidence consequently is hardly conclusive, though from the two sets of
cases tried under a moderate temperature, it is probable that the radicles
are sensitive to contact; and would be more so under favourable conditions.
Fifteen radicles which had germinated in friable peat were suspended
vertically over water. Seven of them served as controls, and they remained
quite straight during 24 h. The tips of the other eight radicles
[page 169]
were just touched with dry caustic on one side. After only 5 h. 10 m. five
of them were slightly curved from the perpendicular and from the side
bearing the little blackish marks. After 8 h. 40 m., 4 out of these 5 were
deflected at angles between 15o and 65o from the perpendicular. On the
other hand, one which had been slightly curved after 5 h. 10 m., now became
straight. After 24 h. the curvature in two cases had considerably
increased; also in four other cases, but these latter radicles had now
become so contorted, some being turned upwards, that it could no longer be
ascertained whether they were still curved from the cauterised side.
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