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.

(2) to (8) These leaves, after 2 hrs. 40 m., had respectively 42, 12, 9, 8, 2, 1, and 0 tentacles inflected, which all re-expanded within 24 hrs., and most of them within a much shorter time.

When the two lots of eight leaves in the solution and in the water were compared after the lapse of 24 hrs., they undoubtedly differed much in appearance.  The few tentacles on the leaves in water which were inflected had after this interval re-expanded, with the exception of one leaf; and this presented the very unusual case of the blade being somewhat inflected, though in a degree hardly approaching that of the two leaves in the solution.  Of these latter leaves, No. 1 had almost all its tentacles, together with its blade, inflected after an immersion of 2 hrs. 30 m.  Leaves No. 2 and 3 were affected at a much slower rate; but after from 24 hrs. to 48 hrs. almost all their tentacles were closely inflected, and the