one lobe; so that the opposite lobe, meeting with no resistance in this
part, went on curving inwards much beyond the medial line. The whole of
the lobe, from which a portion had been cut, was afterwards removed,
and the opposite lobe now curled completely over, passing through an
angle of from 120o to 130o, so as to occupy a position almost at right
angles to that which it would have held had the opposite lobe been
present.
From the curving inwards of the two lobes, as they move towards each
other, the straight marginal spikes intercross by their tips at first,
and ultimately by their bases. The leaf is then completely shut and
encloses a shallow cavity. If it has been made to shut merely by one of
the sensitive filaments having been touched, or if it includes an
object not yielding soluble nitrogenous matter, the two lobes retain
their inwardly concave form until they re-expand. The re-expansion
under these circumstances that is when no organic matter is
enclosed was observed in ten cases. In all of these, the leaves
re-expanded to about two-thirds of the full extent in 24 hrs. from the
time of closure. Even the leaf from which a portion of one lobe had
been cut off opened to a slight degree within this same time. In one
case a leaf re-expanded to about two-thirds of the full extent in 7
hrs., and completely in 32 hrs.; but one of its filaments had been
touched merely with a hair just enough to cause the leaf to close. Of
these ten leaves only a few re-expanded completely in less than two
days, and two or three required even a little longer time. Before,
however, they fully re-expand, they are ready to close [page 307]
instantly if their sensitive filaments are touched. How many times a
leaf is capable of shutting and opening if no animal matter is left
enclosed, I do not know; but one leaf was made to close four times,
reopening afterwards, within six days, On the last occasion it caught a
fly, and then remained closed for many days.
This power of reopening quickly after the filaments have been
accidentally touched by blades of grass, or by objects blown on the
leaf by the wind, as occasionally happens in its native place,* must be
of some importance to the plant; for as long as a leaf remains closed,
it cannot of course capture an insect.
When the filaments are irritated and a leaf is made to shut over an
insect, a bit of meat, albumen, gelatine, casein, and, no doubt, any
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