room was rather low, about 60o (15o.5 Cent.); but the plants had been kept for several days in a very warm greenhouse and thus rendered extremely sensitive.  Special precautions were taken for this set of experiments; a chemist weighed for me a grain in an excellent balance; and fresh water, given me by Prof.  Frankland, was carefully measured.  The leaves were selected from a large number of plants in the following manner:  the four finest were immersed in water, and the next four finest in the solution, and so on till the twenty pairs were complete.  The water specimens were thus a little favoured, but they did not undergo more inflection than in the previous cases, comparatively with those in the solution.

Of the twenty leaves in the solution, eleven became inflected within 40 m.; eight of them plainly and three rather doubtfully; but the latter had at least twenty of their outer tentacles inflected.  Owing to the weakness of the solution, inflection occurred, except in No. 1, much more slowly than in the previous trials.  The condition of the eleven leaves which were considerably inflected will now be given at stated intervals, always reckoning from the time of immersion:—­

(1) After only 8 m. a large number of tentacles inflected, and after 17 m. all but fifteen; after 2 hrs. all but eight in- [page 159] flected, or plainly sub-inflected.  After 4 hrs. the tentacles began to re-expand, and such prompt re-expansion is unusual; after 7 hrs. 30 m. they were almost fully re-expanded.

(2) After 39 m. a large number of tentacles inflected; after 2 hrs. 18 m. all but twenty-five inflected; after 4 hrs. 17 m. all but sixteen inflected.  The leaf remained in this state for many hours.

(3) After 12 m. a considerable amount of inflection; after 4 hrs. all the tentacles inflected except those of the two outer rows, and the leaf remained in this state for some time; after 23 hrs. began to re-expand.

(4) After 40 m. much inflection; after 4 hrs. 13 m. fully half the tentacles inflected; after 23 hrs. still slightly inflected.

(5) After 40 m. much inflection; after 4 hrs. 22 m. fully half the tentacles inflected; after 23 hrs. still slightly inflected.

(6) After 40 m. some inflection; after 2 hrs. 18 m. about twenty-eight outer tentacles inflected; after 5 hrs. 20 m. about a third of the tentacles inflected; after 8 hrs. much re-expanded.

(7) After 20 m. some inflection; after 2 hrs. a considerable number of tentacles inflected; after 7 hrs. 45 m. began to re-expand.

(8) After 38 m. twenty-eight tentacles inflected; after 3 hrs. 45 m. thirty-three inflected, with most of the submarginal tentacles sub-inflected; continued so for two days, and then partially re-expanded.

(9) After 38 m. forty-two tentacles inflected; after 3 hrs. 12 m. sixty-six inflected or sub-inflected; after 6 hrs. 40 m. all but twenty-four inflected or sub-inflected; after 9 hrs. 40 m. all but seventeen inflected; after 24 hrs. all but four inflected or sub-inflected, only a few being closely inflected; after 27 hrs. 40 m. the blade inflected.  The leaf remained in this state for two days, and then began to re-expand.