These poured forth much secretion, were blackened, and ultimately died;
but the tentacles moved only slightly. The dose, small as it was,
evidently was too great, and the result was the same as with particles
of the carbonate of ammonia.
Half-minims of a solution of one part to 437 of water were placed on
the discs of three leaves and acted most energetically, causing the
tentacles of one to be inflected in 15 m., and the blades of all three
to be much curved inwards in 2 hrs. 15 m. Similar drops of a solution
of one part to 1312 of water, (1 gr. to 3 oz.) were then placed on the
discs of five leaves, so that each received the 1/2880 of a grain
(.0225 mg.). After 8 hrs. the tentacles of four of them were
considerably inflected, and after 24 hrs. the blades of three. After 48
hrs. all five were almost fully re-expanded. I may mention with respect
to one of these leaves, that a drop of water had been left during the
previous 24 hrs. on its disc, but produced no effect; and that this was
hardly dry when the solution was added.
Similar drops of a solution of one part to 1750 of water (1 gr. to 4
oz.) were next placed on the discs of six leaves; so that each received
1/3840 of a grain (.0169 mg.); after 8 hrs. three of them had many
tentacles and their blades inflected; two others had only a few
tentacles slightly inflected, and the sixth was not at all affected.
After 24 hrs. most of the leaves had a few more tentacles inflected,
but one had begun to re-expand. We thus see that with the more
sensitive leaves the 1/3840 of a grain, absorbed by the central glands,
is enough to make many of the exterior tentacles and the blades bend,
whereas the 1/1920 of a grain of the carbonate similarly given produced
no effect; and 1/2880 of a grain of the nitrate was only just
sufficient to produce a well-marked effect.
A minute drop, about equal to 1/20 of a minim, of a solution of one
part of the phosphate to 875 of water, was applied to the secretion on
three glands, each of which thus received only 1/57600 of a grain
(.00112 mg.), and all three tentacles became inflected. Similar drops
of a solution of one part to 1312 of water (1 gr. to 3 oz.) were now
tried on three leaves; a drop being applied to four glands on the same
leaf. On the first leaf, three of the tentacles became slightly
inflected in 6 m., and re-expanded after 8 hrs. 45 m. On the second,
two tentacles became sub-inflected in 12 m. And on the third all four
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