to 750 oz.). Each leaf thus received 1/12000 of a grain (.0054 mg.) of the salt; and all four were greatly inflected.
(1) After 1 hr. all the outer tentacles but one inflected, and the blade greatly so; after 7 hrs. began to re-expand.
(2) After 1 hr. all the outer tentacles but eight inflected; after 12 hrs. all re-expanded.
(3) After 1 hr. much inflection; after 2 hrs. 30 m. all the tentacles but thirty-six inflected; after 6 hrs. all but twenty-two inflected; after 12 hrs. partly re-expanded.
(4) After 1 hr. all the tentacles but thirty-two inflected; after 2 hrs. 30 m. all but twenty-one inflected; after 6 hrs. almost re-expanded.
Of the four corresponding leaves in water:--
(1) After 1 hr. forty-five tentacles inflected; but after 7 hrs. so many had re-expanded that only ten remained much inflected.
(2) After 1 hr. seven tentacles inflected; these were almost re-expanded in 6 hrs.
(3) and (4) Not affected, except that, as usual, after 11 hrs. the short tentacles on the borders of the disc formed a ring.
There can, therefore, be no doubt about the efficiency of the above solution; and it follows as before that each gland of No. 1 could have absorbed only 1/2412000 of a grain (.0000268 mg.) and of No. 2 only 1/2460000 of a grain (.0000263 mg.) of the phosphate.
Seven leaves were immersed, each in thirty minims of a solution of one part to 437,500 of water (1 gr. to 1000 oz.). Each leaf thus received 1/16000 of a grain (.00405 mg.). The day was warm, and the leaves were very fine, so that all circumstances were favourable.
(1) After 30 m. all the outer tentacles except five inflected, and most of them closely; after 1 hr. blade slightly inflected; after 9 hrs. 30 m. began to re-expand.
(2) After 33 m. all the outer tentacles but twenty-five inflected, and blade slightly so; after 1 hr. 30 m. blade strongly inflected and remained so for 24 hrs.; but some of the tentacles had then re-expanded.
(3) After 1 hr. all but twelve tentacles inflected; after 2 hrs. 30 m. all but nine inflected; and of the inflected tentacles all excepting four closely; blade slightly inflected. After 8 hrs. blade quite doubled up, and now all the tentacles excepting [page 162] eight closely inflected. The leaf remained in this state for two days.
(4) After 2 hrs. 20 m. only fifty-nine tentacles inflected; but after 5 hrs. all the tentacles closely inflected excepting two which were not affected, and eleven which were only sub-inflected; after 7 hrs. blade considerably inflected; after 12 hrs. much re-expansion.
(5) After 4 hrs. all the tentacles but fourteen inflected; after 9 hrs. 30 m. beginning to re-expand.
(6) After 1 hr. thirty-six tentacles inflected; after 5 hrs. all but fifty-four inflected; after 12 hrs. considerable re-expansion.
(7) After 4 hrs. 30 m. only thirty-five tentacles inflected or sub-inflected, and this small amount of inflection never increased.
Now for the seven corresponding leaves in water:--
(1) After 4 hrs. thirty-eight tentacles inflected; but after 7 hrs. these, with the exception of six, re-expanded.
(2) After 4 hrs. 20 m. twenty inflected; these after 9 hrs. partially re-expanded.
(3) After 4 hrs. five inflected, which began to re-expand after 7 hrs.
(4) After 24 hrs. one inflected.
(5), (6) and (7) Not at all affected, though observed for 24 hrs., excepting the short tentacles on the borders of the disc, which as usual formed a ring.
A comparison of the leaves in the solution, especially of the first five or even six on the list, with those in the water, after 1 hr. or after 4 hrs., and in a still more marked degree after 7 hrs. or 8 hrs., could not leave the least doubt that the solution had produced a great effect. This was shown not only by the vastly greater number of inflected tentacles, but by the degree or closeness of their inflection, and by that of their blades. Yet each gland on leaf No. 1 (which bore 255 glands, all of which, excepting five, were inflected in 30 m.) could not have received more than one-four-millionth of a grain (.0000162 mg.) of the salt.