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Bot. Zeitung 1860 p. 229 "Ueber die Reizbarkeit

Dr Th. Nitschke — gives bibliography up to this date of 1860.— the oldest discover & paper by Dr Roth in 1782 one of the best

I may want this in going over again der Blatter von Drosera rotundifolia.

p. 231 (a) discovered & insists on importance of disc of leaf curling over object

p. 231. (b) Maintains that tentacles direct themselves to any point (& do not as I thought nearly only bow in)

This I must attend to, when investigating lines of motor influence.— Put very small atoms of meat & see directions; & before long ones have touched, change position & see if same tentacle will bend obliquely in another direction.

There must be convergence, from position of tentacles— is not this cause of his mistake. If they can bend at all laterally, nerve nerve-influences must be sent to one side of tentacles—

Most important.

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p. 232 (b) insects which are caught are killed in about 1/4 of hour, apparently by the Ueber die Zeizbartheit

close closure of their tracheæ with the viscid secretion.

p 233 (a) touching glands even repeatedly causes no movement!! (error.)

p 233 (b) dead insects cause slower movement than live ones (good.) showing greater importance this of continued pressure than of absorption — He often employed small dead beetle, & those probably wd yield little nutriment.

The amt of irritation is in proportion to size of irritating object, & I believe this is true — He was fully aware that inorganic objects caused movement.

p. 233 (b) does not give strength of sulphur sulphuric muriatic & nitric acids used; & they did not seem to act on marginal tentacle, So do not quote.—

p. 234 (a) strychnine, morphia, acetic acid — Prussic acid alcohol: these no effect, when dripped on leaf— Pricking & cutting leaves does not cause inflection.— I found same by cutting with Lancet.

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p. 237 or 237 (b) fastened small dead beetle with viscid secretion to pedicels, & the backs (p 238a) of leaves, & he declares the tentacles bent back, & in one case by affixing big object, to back, while solid leaf curled back.— When fixed to one tentacle (239 (a)) that tentacle remained stationary, whilst adjoining ones bent to it! ! When fixed on back marginal tentacles bent so much backwards, that they touched organic or inorganic object with their glands.— Has seen this repeatedly, & in nature believes that the tentacles leaves with much reflexed tentacles, have accidentally touched something behind — (I believe reflexion occur when leaves vertical.)— (N.B. When whole solid leaf is curved into cup, how in basal part of tentacle is this then curved?) Most important to try on backs & pedicels the viscid secretion: try raw also, raw-meat pounded in syrup or gum.— If the former alone acts shows

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how peculiar is viscid secretion — if with syrup acts, shows endosmose — If tentacles really bend back this will show that nerve-influence is transmitted in every conceivable direction.

p. 239. (a) when object placed on one side of leaf, influence radiates centrifugally in all directions! did he not put object beyond medial line?

p. 239 (a) concludes that irritation is transmitted equally in all directions in plane of leaf (p. 238 (b) all parts of "blatt-lamina" & appendages can be irritated)

p. 239 (b) X explains the irregular incurving of disc of leaf on mechanical principles, as flat circular leaf cannot be thus folded all round — (at least without great contraction of inner & outer laminæ C.D.)

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p. 240 (a) admits chief curvature of tentacles at base.—

p 240. (a) insists most strongly that curvature of tentacles is always towards irritating object; & if that if X the object is removed, they continue moving to the point in question, & even ones not already started move towards same point. (An excellent experiment, (p 241(a) suggested by him) wd be to lay little straw or stick obliquely across leaf, & then see how tentacles point: this wd. be decisive: if so, I must own observed & discovered by him.— If so, motor force must radiate from every single tentacle centrifugally & cause contraction towards such points.)

p 241 (a) I think he alludes to leaf rising up relatively True to the footstalk.— Describes in great detail the curvature of leaf itself — the pedicel footstalk prevents basal part curving in. — lateral run common. The end curvature (Mem. one side alone curving inwards He alludes to this fact).— 3 rounded angles, he says, commonest form of inwards curvature,

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p 243 (b) thinks the tentacles mainly moving before te "blatt-lamina" is partly due to the mass of the latter; but I doubt on account of Dionæa, far more massive & yet moves quicker.—

245 (a & b) age of leaf, not too young or too old, chief determinant of degree of irritability, which accounts into accompanies degree of amount of secretion.

p 245 (b) living insects, from their movements, touching more glands or surface, excite more than same insects dead. —greater the area of surface touched greater the excitement.

Says in other respects living insects act act like lifeless other objects of same size (so knows nothing of after effects)

p. 246. warm weather good for irritability — cold weather bad, & dull rainy weather only so far bad, as accompanied by cold, which makes leaves very torpid.—

p 247 Temperature great cause of different sensibility. (He has not yet noticed having recently acted.)

(If I find, as I suspect, more active during early year, perhaps owing to average daily temperature.)

p. 247 (b) It is less light than Heat, which produces effect & he gives some evidence.— seems to be relative

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p 247 (a) heat on more than absolute heat, so that same day, so more sensitive in midday than during morning or evening —

Less sensitive during Autumn.—

Too great warmth makes them leaves torpid —

The Activity seems to depend on the processes of life gong on vigorously rather than on the power of direct temperature.—

p 247 (b) Drosera does not sleep.—

p. 248 (a) living ants caused move the nascent tentacles to bend in 5' — the marginal ones began bending in 10' & it was 1° before, they reached centre (these are all cases rather active) — Milde used "flies" & use marginal tentacles begin to bend in 3'. Nitschke he attributes this quicker movement to greater size of flies — probably also in part to nature, —animal matter being more easily absorbed from them.— A straw caused movement in nearest tentacles in 5'-10' — a dead ant or a seed required 1/2 hour hour for nearest tentacle to be inflected.— In rainy weather living ant took 1° before nearest nearest tentacles moved —

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p 248 (b) leaf with a living ant placed on them released from tentacles them, when weather fine, in 4-5 days — the laminæ of leaf first opens, & then the marginal tentacles & then the X sub-marginals, so in reversed order to that of clasping — Lifeless objects are released in 2-3 days — accounts for this by the leaf having been less irritated —

It is true, as he says, tentacles moved by slight irritation expand quicker — the tentacles in such cases, which stand nearest to object will expand in one day — In cold weather expand tentacles expand in shorter time, than during warm weather; so often live ant placed on leaf, it will then expand on next day.

Hence amount amount of irritation, nature of weather, &, as I show, the nature of substance, in yielding nutritious matter, all aid in determining the period of reexpansion.─

It is very odd that fragments of insects left on leaf do not continue to cause irritation — Try leaf in tentacles in this condition with new object, like raw-meat — Do they get accustomed to any particular body? (over)

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p 249 (a) N. was aware of secretion getting less during during reexpansion, — & he says you can tell when tentacles are again active by renewed secretion.—

I had better say object can often be blown off by the drying up of the glands.—