AND HABITS OF
CHARLES DARWIN, F.R.S.
JOHN MURRAY, ALBEMARLE STREET.
ascertain more precisely what amount of movement each
internode underwent, I kept a potted plant, during the
night and day, in a well-warmed room to which I was
confined by illness. A long shoot projected beyond the
upper end of the supporting stick, and was steadily
revolving. I then took a longer stick and tied up the
shoot, so that only a very young internode, 1¾ of an
inch in length, was left free. This was so nearly
upright that its revolution could not be easily
observed; but it certainly moved, and the side of the
internode which was at one time convex became concave,
which, as we shall hereafter see, is a sure sign of the
revolving movement. I will assume that it made at least
one revolution during the first twenty-four hours.
Early the next morning its position was marked, and it
made a second revolution in 9 hrs.; during the latter
part of this revolution it moved much quicker, and the
third circle was performed in the evening in a little
over 3 hrs. As on the succeeding morning I found that
the shoot revolved in 2 hrs. 45 m., it must have made
during the night four revolutions, each at the average
rate of a little over 3 hrs. I should add that the
temperature of the room varied only a little. The shoot
had now grown 3½ inches in length, and carried at its
extremity a young internode 1 inch in length, which
showed slight changes in its curvature. The next or
ninth revolution ...............