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Show 350 GLANDULAR HAIRS, CHAP. XV. employed. A solution of t~is strength paraly~es all_ movement in Drosera, but does not kill the protoplasm; a still stronger solution prevents the protoplasm from aggregating into the ordinary full-sized globular masses, and these, though they do not disintegrate, become granular and opaque. In nearly the same manner, too hot watEJr and· certain solutions (for instance, of the salts of soda and potash) cause at first an imperfect kind of aggre~ation in. the cells of Drosera; the little masses afterwards breaking up Into granular or pulpy brown matter. All the foregoing experiments were made on flowerstems, but a piece of a leaf was immersed for 30 m. in a strong solution of the carbonate (one part to 109 of water), and little globular mas~es of matter appeared in all the glands, which before contained only limpid fluid. I made also several experiments on the action of the vapour of the carbonate on the glands; but will give only a few cases. The cut end of the footstalk of a young leaf was proter;ted with sealing-wax, and was then placed under a small bell-glass, with a large pinch of the carbonate. After 10m. the glands showed a considerable degree of aggregation, and the protoplasm lining the cells of the pedicels was a little separated from the walls. Another leaf was left for 50 m. with tho same result, excepting that the hairs became throughout their whole length of a brownish colour. In a third leaf, which was exposed for 1 hr. 50 m., there was much aggregated matter in the glands; and some of the masses showed signs of breaking up into brown granular matter. This leaf was again placed in the vapour, so that it was exposed altogether for 5 hrs. 30m.; and now, though I examined a large number of glands, aggregated masses were found in only two or three ; in all the otherR, the masses, which before had been globular, were converted into brown, opaque, granular matter. We thus sec that exposure to the vapour for a considerable time produces the same effects as long immersion in a strong solution. In both cases there could hardly be a doubt that the salt had been absorbed chiefly or exclusively by the glands. On another occasion bits of damp fibrin, drops of a weak infusion of raw meat and of water, were left for 24 hrs. on some leaves; the hairs were then examined, but to my surprise differed in no respect from others which had not been touched by these fluids. Most bf the cells, however, included hyaline, motionless little spheres, which did not seem to consist of protoplasm, but, I suppose, of some balsam or essential oil. Pelargonium zonale (var. edged with white).-The leaves CHAP. XV. THEIR are clothed with nun pointed; other ·uing 1: length. The crland on ] il l to contain only lim I id rlni : n s from beneath the con:rin0 ~1. -~ ~. : of carbonate of amm nia 1 · extremely small d -: ... cri there were ·icrn of ag rc~: ti<. n i li1 ht hairs; and after 5 m. m: y , ~ 1l ~ )1 1 : 1 :lll ht·(n 11 tint appeared in all of th m · "imi: r ~ 1 h ''. l1 t 1: r: < r, l <'ino· found in the larcre crla.nd"' ~ I ng\r 1: · . .\fit. r ilw ~Pl'<'i men had been left for 1 hr. in 1 e 11ti 1: n~ )f th<. ~mnll<•t· globules had chancred h .ir I- '· · : : n t · <. r t hrt < :'l 'lW 1 '.. or small sphere (for I kn " n hi h ht. ~ <. rt') of : rat h r darker tint app r d wi hin th 1:. 1 "ll' ~..,·1 )hul '.. Little globules could n w l: ..; en in m "\ f th ~ npp rm :t cells of the pedicel , and th r 01 h 'mi" linin(l" wa lightly separated from the wall, of e low r "' 11 .... fter .... hr . · 0 m. from the time of fir t imrn r2i n tb hrg d bul within the glands of the longer hair'"' w r c n rt d in o rna, of darker brown granular matter. H nc from "What " have en with Primula inen i , here can little doubt that the e masses originally conffi ted of linng proto lasm. A drop of a weak infu ion of raw mea "Wa placed on a leaf, and after 2 hr . 30m. many phere could be .,een 'Within tho glands. These spher , when looke a again after 30 m., had slightly changed their po ition and form , and one had eparated into two; but the change were no quite like tho e which the protoplasm of Dro era undergoes. The. hairs, moreover, had not been examined before immer ·on, and there were similar spheres in some gland which had not been touched by the infusion. Erica tetralix.-A few long glandular hairs project from tho · margins of the upper surfaces of the leaves. The pedicels aro formed of several Tows of cell., and upporl rather large glolJulttr heads, secreting vi cid rna ter, by which minute insects ar • occasionally, though rarely, caught. orne leaves were l•ft fol' 23 hrs. in a weak infn ion of raw meat and in water and the hairs were then compared, but they differed very ]itt lo or .not at all. In both cases the contents of the cells seemed J'~tLlt .,. mo~e .granular than they were before; but the granuloH di<t not, exhibit any movement. Other leav8s were left for 23 hrH. in ,~ solution of one part of carbonate of ammonia to 2J H oJ' wrd t'l' and here again the granular matter appear<:u to havo htet't~rt~w·i |
