Sir J. C. Bose gave the following Discourse on the 'Night-Watch of
Nymphaea,' at the Bose Institute, on the 24th January, 1919.
[Sir J. C. Bose's discourse delivered at the Bose Institute, on the 24th
January, 1919, dealt with the mysterious phenomenon of recurrent opening
and closure of flowers. Some of them open in the morning and close in
the evening; others do exactly the opposite opening at night and closing
during the day. These various effects have been described as the
'waking' and 'sleep' movements of plants. The subject had attracted the
attention of plant physiologists for more than half a century. After
summarising the various results lost in his recent work says that no
satisfactory explanation of the sleep movements of plants has yet been
forthcoming and that the true theory can only be established after new
and exhaustive research. This investigation has been in progress at Sir
J. C. Bose's laboratory for the last five years; and special automatic
recorders have been invented by means of which numerous plants have been
recording their movements for every hour of the day and night and for
many days in succession.]
In course of his discourse the lecturer said "The poets have forestalled
the men of science. Why does the water-lily 'Kumud or Nymphaea' keep
awake all night long and close her petals during the day? Because the
water-lily is the lover of the Moon and like the human soul expanding at
the touch of the beloved, the lily opens out her heart at the touch of
the moon beam, and keeps watch all night long; she shrinks affrighted by
the rude touch of the Sun, and closes her petals during the day. The
outer floral leaves of the lily are green, and in the day time the
closed flowers are hardly distinguishable from the broad green leaves
which float on the water. The scene is transformed in the evening as if
by magic, and myriads of glistening white flowers cover the dark water.
"The recurrent daily phenomenon has not only been observed by the poets,
but an explanation offered for it. It is the moonlight then that causes
the opening of the lily, and the sunlight the movement of closure. Had
the poet taken out a lantern in a dark night; he would have noticed that
the lily opened at night in total absence of the moon; but a poet is not
expected to carry a lantern and peep out in the dark; that inordinate
curiosity is characteristic only of the man of science. Again the lily
does not close with the appearance of the sun; for the flower often
remains awake up to eleven in the forenoon. A French dictionary maker
saw Cuvier, the Zoologist about the definition of the crab as 'a little
red fish which walks backwards.' 'Admirable,' said Cuvier. 'But the crab
is not necessarily little, nor is it red till boiled; it is not a fish,
and it cannot walk backwards. But with these exceptions your definition
is perfect.' And so also with the poet's description of the movement of
the lily, which does not open to moonlight, nor yet close to the sun."