Lastly, eight leaves were immersed, each in thirty minims of a solution
of one part of the phosphate to 21,875,000 of water (1 gr. to 5000
oz.). Each leaf thus received 1/80000 of a grain of the salt, or .00081
mg. I took especial pains in selecting the finest leaves from the
hot-house for immersion, both in the solution and the water, and almost
all proved extremely sensitive. Beginning as before with those in the
solution:
(1) After 2 hrs. 30 m. all the tentacles but twenty-two inflected, but
some only sub-inflected; the blade much inflected; after 6 hrs. 30 m.
all but thirteen inflected, with the blade immensely inflected; and
remained so for 48 hrs.
(2) No change for the first 12 hrs., but after 24 hrs. all the
tentacles inflected, excepting those of the outermost row, of which
only eleven were inflected. The inflection continued to increase, and
after 48 hrs. all the tentacles except three were inflected, [page 165]
and most of them rather closely, four or five being only sub-inflected.
(3) No change for the first 12 hrs.; but after 24 hrs. all the
tentacles excepting those of the outermost row were sub-inflected, with
the blade inflected. After 36 hrs. blade strongly inflected, with all
the tentacles, except three, inflected or sub-inflected. After 48 hrs.
in the same state.
(4) to (8) These leaves, after 2 hrs. 30 m., had respectively 32, 17,
7, 4, and 0 tentacles inflected, most of which, after a few hours,
re-expanded, with the exception of No. 4, which retained its thirty-two
tentacles inflected for 48 hrs.
Now for the eight corresponding leaves in water:
(1) After 2 hrs. 40 m. this had twenty of its outer tentacles
inflected, five of which re-expanded after 6 hrs. 30 m. After 10 hrs.
15 m. a most unusual circumstance occurred, namely, the whole blade
became slightly bowed towards the footstalk, and so remained for 48
hrs. The exterior tentacles, excepting those of the three or four
outermost rows, were now also inflected to an unusual degree.
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