forty minims of a solution of one part to 10,500 of water; and assuming that they absorbed equally, each leaf received 1/1152 of a grain (.0562 mg.).  After 1 hr. 20 m. many of the tentacles on all four leaves were somewhat inflected.  After [page 151] 5 hrs. 30 m. two leaves had all their tentacles inflected; a third leaf all except the extreme marginals, which seemed old and torpid; and the fourth a large number.  After 21 hrs. every single tentacle, on all four leaves, was closely inflected.  Of the four leaves placed at the same time in water, one had, after 5 hrs. 45 m., five marginal tentacles inflected; a second, ten; a third, nine marginals and submarginals; and the fourth, twelve, chiefly submarginals, inflected.  After 21 hrs. all these marginal tentacles re-expanded, but a few of the submarginals on two of the leaves remained slightly curved inwards.  The contrast was wonderfully great between these four leaves in water and those in the solution, the latter having every one of their tentacles closely inflected.  Making the moderate assumption that each of these leaves bore 160 tentacles, each gland could have absorbed only 1/184320 of a grain (.000351 mg.).  This experiment was repeated on three leaves with the same relative amount of the solution; and after 6 hrs. 15 m. all the tentacles except nine, on all three leaves taken together, were closely inflected.  In this case the tentacles on each leaf were counted, and gave an average of 162 per leaf.

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.