Insectivorous plants . over a bit of meat placedou the disc. becomes sliglitly incurved; the distal half in all casesremaining straight. The short tentacles in the centreof the disc when directly excited, do not become in-flected ; but they are capable of inflection if excitedby a motor impulse received from other glands at adistance. Thus, if a leaf is immersed in an infusionof raw meat, or in a weak solution of ammonia (if the Chaf. I. ACTION OF THE PARTS. 11 solution is at all strong, the leaf is paralysed), all theexterior tentacles bend inwards (see fig. 4), exceptingthose near the centre
Insectivorous plants . over a bit of meat placedou the disc. becomes sliglitly incurved; the distal half in all casesremaining straight. The short tentacles in the centreof the disc when directly excited, do not become in-flected ; but they are capable of inflection if excitedby a motor impulse received from other glands at adistance. Thus, if a leaf is immersed in an infusionof raw meat, or in a weak solution of ammonia (if the Chaf. I. ACTION OF THE PARTS. 11 solution is at all strong, the leaf is paralysed), all theexterior tentacles bend inwards (see fig. 4), exceptingthose near the centre, which remain upright; but thesebend towards any exciting object placed on one sideof the disc, as shown in fig. 5. The glands in fig. 4may be seen to form a dark ring round the centre ; andthis follows from the exterior tentacles increasing inlength in due proportion, as they stand nearer to thecircumference. The kind of inflection which the tentacles undergois best shown when the gland of one of the long exterior. Fig. 6.(Brosera rotundifolia.) Diagram showing one of the exterior tentacles closely inflected; the two adjoiningones in their ordinary position. tentacles is in any way excited; for the surroundingones remain unaffected. In the accompanying outline(fig. 6) we see one tentacle, on which a particle ofmeat had been placed, thus bent towards the centre ofthe leaf, with two others retaining their originalposition. A gland may be excited by being simplytouched three or four times, or by prolonged contactwith organic or inorganic objects, and various fluids. Ihave distinctly seen, through a lens, a tentacle begin-ning to bend in ten seconds, after an object had been 12 DROSERA EOTUNDirOLIA. Chap. I, placed on its gland; and I have often seen stronglypronounced inflection in under one minute. It is sur-prising liow minute a particle of any substance, suchas a bit of thread or hair or splinter of glass, if placedin actual contact with the surface of a gland, sufficesto cau
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