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Show 20 DROSERA ROTUNDIFOLIA. CHAP. II. exterior tentacles, near their bases, and does ~ot (as will hereafter be proved) first travel up the pedicels to the glands, to be then reflected back to the bending place. Nevertheless, some influence does trave~ up to the o·lands, causing them to secrete more copiously, and ~he secretion to become acid. This latter fact i~, I believe, quite new in the physiolo~y of plant~; it has indeed only recently be n estabhsh d that In the animal kingdom an influence can be transmitted along the nerves to glands, modifying th ir power of secretion, independently of the state of the blood-vessels. The Inflection of the Exterior Tentacles from the Glands of the Disc being ·excited by Repeated Touches, or by ObJects left in Contact with them. The central glands of a leaf were irritat d with a sn1all stiff camel-hair brush, and in 70 m. (minutes) several of the outer tentacles were inflected; in 5 hrs. (hours) all the sub-marginal tentacles were inflected; next morning after an interval of about 22 hrs. they were fully re-expanded. In all the following cases the period is reckoned from the time of first irritation. Another leaf treated in the same manner had a few tentacles inflected in 20 m. ; in 4 hrs. all the submarginal and ~orne of the extreme marginal tentacles, as well as the edge of the leaf itself, were infl cted; in 17 hrs. they had recovered their proper, expanded position. I then put a dead fly in the centre of the last-mentioned leaf, and next morning it was closely clasped; five days afterwards the leaf re-expanded, and the tentacles, with their glands surrounded by secretion, were ready to act again. Pai·ticles of meat, dead flies, bits of paper, wood, dried moss, sponge, cinders, glass, &c., were repeatedly CHAP. II. INFLECTION INDIRECTLY CAUSED. 21 ~Jlace~ on lea~es, and these objects were well embraced In vanous periods from 1 hr. to as long as 24 hrs., and set free again, with the leaf fully re-expanded, in from one or two, to seven or even ten days, according to the nature of the object. On a leaf which had naturally caught two fl~es, and therefore h~d already cl~sed and reopened eith~r once ?r more probably twice,. I put a fresh fly : In 7 hrs. It was moderately, and In 21 hrs. thoroughly well, clasped, with the edges of the leaf inflected. In two days and a ha~f the leaf h~d nearl~ re-expanded; as the exciting obJe~t was an Insect, this unusually short period of inflecti~ n wa~, no doubt, ~ue to the leaf having recently been In action. Allowing this same leaf to rest for only a single day, I put on another fly, and it again closed, but now very slowly; nevertheless, in less than two days it succeeded in thoroughly clasping the flv. . When a smal~ object is placed on the · glands of the ~Isc,. on one side of a leaf, as near as possible to Its circumference, the tentacles on this side are :first affected, those on the opposite side much later, or, as often. occur_red, ~ot at all. This was repeatedly proved by tnals With hits of meat ; but I will here give only th.e case. of a minute fly, naturally caught and still ahve, which I found adhering by its delicate feet to the glands on the extreme left side of the central disc. The marginal tentacles on this side closed inwards and killed . the _fly, and after a time the edge of the leaf ?n this side also became inflected, and thus re~ained for several days, whilst neither the tentacles nor the edge on the opposite side were in the least affected. If young and active leaves are selected inoro-anic . l ' 5 partie es not larger than the head of a small pin, placed on the central glands, sometimes cause the |