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Show 160 DROSER.A. ROTUNDIFOLIA. CHAP. VII. 4o m. all the outer tentacles except twenty-five were i~flected, as was the blade in a strongly marked .manner. After 24 hrs. every t ent ac 1e ex Cept one was closely Inflected, an· d dt h.ec blade 1 t 1 doubled over Thus the leaf remaine 10r two was com P e e Y · dd l t tJ th days wh en I· t b eg an to re-expand. I m·a y a t 1ha t 1· e fl tr ede latte'r 1e aves (N os · 9' 10' and 11) were still somew a In ec e a·f ter thr ee d ays. The tentacles in but few of ·t hese ele· vetnh leaves became cl ose l y I'n flected within so sho. rt a time as In e pre-vious experiments with stronger solutiOns. . . . W 711' turn to the twenty corresponding leaves Ill water. Ninee hwa1 d nnoowne of their outer tentacles 1· n tl ec t ed ; ni·n e ot he rs had from one to three inflected ; and these re-expanded after 8 hrs. The remaining two leaves were moderately affectecl; one having six tentacles inflected in 34m.; the oth_er twenty-three I· nf l ec t e d I· n 2 hr·s . 12 m . ·, and both t.h us l'emained for 24 hrs. None of these leaves had their blades Inflected. So that tb~ cont t between the twenty leaves in water and the twenty m the s~~:tion was very great, both within the first hour and after from 8 to 12 hrs. had elapsed. . Of the leaves in the solution, the glands ?n 1e~f No. 1, which · 2 h had all its tentacles except eight mflected, were Icno untedr sa. nd found to Be 202. Subtracti·n g the _ei·g ht , eac l1 g1 a n d could have received only the 155 ~ 000 of a grain ('0000411 ~g.) of the phosphate. Leaf No. 9 had _213 tentacles, ~11 of which, with the exception of four, were Inflect~d after 24 hrs., but none of them closely ; the blade was also 1nfiect~d ; eaeh gland could have received only the 167 ~ 000 of a gram, or ·~000387 mg. Lastly, leaf No. 11, which had after 24 hrs. all Its te~tacles, except one, closely inflected, as well as the blade, bme the unusually large number of 252 tentacles; and on the same principle as before, each gland could have absorbed only the _J __ of a g:rain, or ·0000322 mg. 200HOOO '-' With respect to the following experiments? I must_ premis~ that the leaves, both those placed in the solutw~s and In wate1, were taken from plants which bad been kept In a very warm greenhouse during the winter. They were t~1_1s rendered extremely sensitive, as was shown by water exCitmg th~I?- much more than in the previous experiments. Before g1v1~g ~y observations, it may be well to l'emind the reader that, JUdgm.g from thirty-one fine leaves, the average number of tentacles JS ] ~2, and that the outer or exterior ones, the moveme~ts ?f which are alone significant, are to the short ones on the disc m the proportion of about sixteen to nine. CHAP, VII. PJ-IOSPHATE OF AMMONIA. 161 Four leaves were immersed as before, each in thirty minims of a solution of one part to R28,125 of water (1 gr. to 750 oz.). Each leaf thus received 12 600 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 tore-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. 30m. 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 brs, so many bad 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 Ting. 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 241 ~ 000 of a grain (0000268 mg.) and of No. 2 only 246 ~ 000 of a grain ('0000263 mg.) of the phosphate. Seven leaves were immersed, each in thirty mimms of a solution of one part to 437,500 of water (1 gr. to 1UOO oz.). Each leaf thus received 16 ~00 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. 30m. began tore-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 hrfl. 30 m. all but nine inflected; and of the inflected tentacles all excepting four closely; blade slightly inflected. After t) hrs. blade quite doubled up, and now all the tentacles excepting M |