The following experiments were tried during the summer of 1873, by placing the leaves, each in a separate watch-glass and pouring over it thirty minims (1.775 ml.) of the solution; other leaves being treated in exactly the same manner with the doubly distilled water used in making the solutions. The trials above given were made several years before, and when I read over my notes, I could not believe in the results; so I resolved to begin again with moderately strong solutions. Six leaves were first immersed, each in thirty minims of a solution of one part of the nitrate to 8750 of water (1 gr. to 20 oz.), so that each received 1/320 of a grain (.2025 mg.). Before 30 m. had elapsed, four of these leaves were immensely, and two of them moderately, inflected. The glands were rendered of a dark red. The four corresponding leaves in water were not at all affected until 6 hrs. had elapsed, and then only the short tentacles on the borders of the disc; and their inflection, as previously explained, is never of any significance. Four leaves were immersed, each in thirty minims of a solution of one part to 17,500 of water (1 gr. to 40 oz.), so that each received 1/640 of a grain (.101 mg.); and in less than 45 m. three of them had all their tentacles, except from four to ten, inflected; the blade of one being inflected after 6 hrs., and the blade of a second after 21 hrs. The fourth leaf was not at all affected. The glands of none were darkened. Of the corresponding leaves [page 152] in water, only one had any of its exterior tentacles, namely five, inflected; after 6 hrs. in one case, and after 21 hrs. in two other cases, the short tentacles on the borders of the disc formed a ring, in the usual manner. Four leaves were immersed, each in thirty minims of a solution of one part to 43,750 of water (1 gr. to 100 oz.), so that each leaf got 1/1600 of a grain (.0405 mg.). Of these, one was much inflected in 8 m., and after 2 hrs. 7 m. had all the tentacles, except thirteen, inflected. The second leaf, after 10 m., had all except three inflected. The third and fourth were hardly at all affected, scarcely more than the corresponding leaves in water. Of the latter, only one was affected, this having two tentacles inflected, with those on the outer parts of the disc forming a ring in the usual manner. In the leaf which had all its tentacles except three inflected in 10 m., each gland (assuming that the leaf bore 160 tentacles) could have absorbed only 1/251200 of a grain, or .000258 mg.