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Show 192 DROSERA ROTUNDIFOLIA. CHAP. VIII. . Tl is acid is far more powerful than formi?, and ~vid~ntly de~d. 1 Half-minim drops of a stronger miXture IS highly pmsonous. to 320 of wa tor) were placed on the ( . part by measure 1 h VIZ. one e of the exterior tentacles, on y t oso discs of five leav~s ~h~o~isc which actually absorbed the acid, on the ?ordersd o Probably the dose was too strong and parabecame, Inflccte · } r drops of a weaker mixture caused much lysed ~ne leaves, o I ss the leaves all died after two days. inflecti~n. ;. neve.~the ~hrec leaves were immersed in ninety minims Prot:wnw .Ac~ · art to 437 of water; in 1 hr. 50 m. there of a mix~ure 0~ o~e b~t after 3 hrs. 40 m. one leaf was greatly ~as no InflectiO~' other two slightly. The inflection ~ontinu.ed Infl~cted, and ththat in 8 hrs. all three leaves were closely mto Increase, so rnin . after 20 hrs., most of the glands were fleeted. Next mo £ g,were almost black. No mucus had been very pale, but s~:ee s::ounding fluid was only just perce~tib1y secreted, and . l After 46 hrs the leaves became shghtly tinte~ of a pale pin ~d tly killed ~·s was afterwards proved to flaccid and were :v:n enthem in ~ater. The protoplasm in the be the c~se by ket!ta~les was not in the least aggregated, but closely Infle.ct~d 't was collecte'l in little brownish masses at towards the~r of a~~~ I cells. This protoplasm was dead, f?r on the ?ottom f in a solution of carbonate of ammoma, no leaVIng ~he lea d Propionic acid is highly poisonous to aggregatwl?-k e~tsue liy acetic acid but induces inflection at a Drosera, I e I s a ' much slower rate. Oleic Acid (given me by Prof. Frankland).-Three_Icavcs.wcre . d . th' acid. some inflection was almost Immediately Imme~sew;~h i~creas~d sHghtly, but then ceased, an~ the leaves caused killed Next 1norning they wore rather shrivelled, an~ seeme of the ~lands had fallen off the tentacles: Drops of thJs m~ny laced on the discs of four leaves; In 40 m. all .the ~~~~a~:~\~'ere greatly inflected, excepting the e_xtromo dma~gmal ones . and many of these after 3 hrs. became Inflectc . ~as led to try this acid from supposing .that .it was pr~scn\(w~~c~ ot seem to be the case)* in ohve ml, the actw~ o w IC ~o:~:malous. Thus drops of this oil placed on the dlSc do n~t 1~ause the outer tentacles to be inflected.; yet when mm~h: d were added to the secretion surroundmg the glands of 0~~~: tentacles, these wore occa~ionally ,db~t t~~ m~1an:n~l~;~.~ inflected. Two leaves were also Immerse m IS Ol ' * See articles on Glycerine anJ Oleic Acid in \Vatts' 'Diet. of Chemistry.' CHAP. VIII. THE EFFECTS OF ACIDS. 193 was no inflection for about 12 hrs.; but after 23 hrs. almost all the tentacles were inflected. Three leaves were likewise immersed in unboiled linseed oil, and soon became somewhat, and in 3 hrs. greatly, inflected. After 1 hr. the secretion round the glands was coloured pink. I infer from this latter fact that tho power of linseed oil to cause inflection cannot be attributed to the albumin which it is said to contain. Carbol?.'c Acid.-Two leaves were immersed in sixty minims of a solution of 1 gr. to 437 of water; in 7 hrs. one was slightly, . and in 24 hrs. both were closely, inflected, with a surprising amount of mucus secreted. These leaves were washed and left for two days in water; they remained inflected; most of their glands became pale, and they seemed dead. This acid is poisonous, but docs not act nearly so rapidly or powerfully as might have been expected from its known destructive power on the lowest organisms. Half-minims of the same solution were placed on the discs of three leaves; after 24 hrs. no inflection of the outer tentacles ensued, and when bits of meat were given them, they became fairly well inflected. Again half-minims of a stronger solution, of one part to 21.8 of water, were placed on the discs of three leaves; no inflection of the outer tontacles ensued; bits of moat were then given as before; one leaf alone became well inflected, the discal glands of the other two appearing much injured and dry. We thus see that the glands of the discs, after absorbing this acid, rarely transmit any motor impulse to the outer tentacles; though these, when their own glands absorb the acid, are strongly acted on. Lact-ic Acid.-Three leaves were immersed in ninety minims of one part to 437 of water. After 48 m. there was no inflection, but the surrounding fluid was coloured pink; after H hrs. 30 m. one leaf alone was a little inflected, and almost all the glands on all three leaves were of a very pale colour. The leaves were then washed and placed in a solution (1 gr. to 20 oz.) of phosphate of ammonia; after about 16 hrs. there was only a trace of inflection. They were left in the phosphate for 48 hrs., and remained in the same state, with almost all their glands discoloured. The protoplasm within the cell. was not aggregated, except in a very few tentacles, the glands of which were not much discoloured. I believe, therefore, that almost all the glands and tentacles had been killed by the acid so suddenly that hardly any inflection was caused. Four leaves were next immersed in 120 minims of a weaker solution, of one part to 875 of water; after 2 hrs. 30 m. the surrounding fluid was quite pink; the glands were pale, but 0 ,J II I I •I |