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* In this particular instance the fifth internode (including the
hypocotyl) was the first which plainly circumnutated and twined round a
stick. We therefore wished to learn whether circumnutation could be
observed in the hypocotyl if carefully observed in our usual manner. Two
seedlings were kept in the dark with filaments fixed to the upper part of
their hypocotyls; but from circumstances not worth explaining their
movements were traced for only a short time. One moved thrice forwards and
twice backwards in nearly opposite directions, in the course of 3 h. 15 m.;
and the other twice forwards and twice backwards in 2 h. 22 m. The
hypocotyl therefore circumnutated at a remarkably rapid rate. It may here
be added that a filament was affixed transversely to the summit of the
second internode above the cotyledons of a little plant 3 ? inches in
height; and its movements were traced on a horizontal glass. It
circumnutated, and the actual distance travelled from side to side was a
quarter of an inch, which was too small an amount to be perceived without
the aid of marks.


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