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Show 164 DROSERA ROTUNDIFOLIA. CHAP. VII. soon re-expanded; (9), (10), (11) and (12) none inflected, though observed for twenty-four hours. · . . Comparing the states of the twelv~ leaves _In water With those in the solution, there could be no doubt that In the latt.er a larger number of tentacles were inflected, and those to~ greater degree; hut the evidence was by no means so clear as In th~ former ex-pen. m e nts with strono-er solutions. It deserves attentiOn that the b • t · · inflection of four of the leaves in the solutiOn wen on Incre~smg during the first 6 hrs., and with sbme of them for a longer tm:e; whereas in the water the inflection of the three leaves winch were the most affected, as well as of all the others, began to decrease during this same interval. It is also remarkabl? that t_be blades of three of the leaves in the solut~on were sb_ghtJy mfle~ ted and this is a most rare event with leaves In water, th;ugh it occurred to a slight extent i~ one (No. ~), which seemed to have been in some manner accidentally exCited. All this shows that the solution produced some effect, though less and at a mueh slower rate than in the previous cases. The small effect produced may, however, b~ accounte_d for in large part by the majority of the leaves having been In a poor condition. Of the leaves in the solution, No.1 bore 200 glands and received _,1.. _ of a o'l'ain of the salt. Subtracting the seventeen tentacles w4HhOiOcOh were0 not inflected, each gland coul d h ave a b sor b ed on Iy +:; l1e _s 7 1s 4· o o_ o of' a oo·-l'ain (·00000738 mg.). This .a mount caused the tentacle bearing each gland to be greatly Inflected. The blade was also inflected. 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 so6oo of a grain of tho salt, or ·Q0081 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 <:ts before with those in the solution:- (1) After 2 hrs. 30 m. all the tentacles but twent~-two inflected, but some only sub-inflected; the blade much Jnflected; after 6 hrs. 30 m. all but thirteen inflected, with the blade immensely inflected; and remained so for 48 brs. (2) No change for the first 12 hrs., but after 24 hrs. all ~be tentacles inflected, excepting those of the outermost row, ?f whJCh onlv eleven were inflected. The inflection continued to mcrease, and after 48 hrs. all the tentacles except t~ree were inflectedJ CHAP. VII. PHOSPHATE OF AMMONIA. 165 and most of them rather closely, four or five being only subinflected. (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 jnfleeted, 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 Gf 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 reexpanded, 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 blade of one quite doubled up. We must therefore admit, incredible as the fact may at first appear, that this extremely weak solution acted on the more sensitive leaves; each of which received only the moo of a geain ('00081 mg.) of the phosphate. Now, leaf No. 3 bore 178 tentacles, and subtracting the three which were not inflected, each e:land could have absorbed only the ___ 1 _ _ . ~ 14000000 . of a grain, or ·00000463 mg. Leaf No. 1, which was strongly acted on within 2 hrs. 30 m., and had all its outer tentacles except thirteen, inflected within 6 hrs. 30m., bore 260 tentacles~ and on .the same principle as before, each gland could have |
