Chap. I.] ACTION OF THE PARTS. 7 



cells, contain, becomes of a brighter green. The petioles bear many 

 multicellular hairs, some of which near the blade are surmounted, 

 according to Nitsohke, by a few rounded cells, which appear to be 

 rudimentary glands. Both surfaces of the leaf, the pedicels of the 

 tentacles, especially the lower sides of the outer ones, and the 

 petioles, are studded with minute papilla; (hairs or trichomes), hav- 

 ing a conical basis, and bearing on their summits two, and occa- 

 sionally three, or even four, rounded cells, containing much proto- 

 plasm. These papillae are generally colourless, but sometimes in- 

 clude a little purple fluid. They vary in development, and gradu- 

 ate, as Nitschke" states, and as I repeatedly observed, into the 

 long multicellular hairs. The latter, as well as the papillte, are 

 probably rudiments of formerly existing tentacles. 



I may here add, in order not to recur to the papillae, that they 

 do not secrete, but are easily permeated by various fluids : thus, 

 when living or dead leaves are immersed in a solution of one part 

 of chloride of gold, or of nitrate of silver, to 437 of water, they 

 are quickly blackened, and the discoloration soon spreads to the 

 surrounding tissue. The long multicellular hairs are not so quickly 

 affected. After a leaf had been left in a weak infusion of raw 

 meat for 10 hours, the cells of the papillae had evidently absorbed 

 animal matter, for instead of limpid fluid they now contained small 

 aggregated masses of protoplasm,' which slowly and incessantly 

 changed their forms. A similar result followed from an immersion 

 of only 15 minutes in a solution of one part of carbonate of 

 ammonia to 218 of water, and the adjoining cells of tl.e tentacles, 

 on which the papillae were seated, now likewise contained aggre- 

 gated masses of protoplasm. We may therefore conclude that, 

 Avhen a leaf has closely clasped a captured insect in the manner 

 immediately to be described, the papillae, which project from the 

 upper surface of the leaf and of the tentacles, probably absorb 

 some of the animal matter dissolved in the secretion; but this 

 cannot be the case with the papillae on the backs of the leaves or 

 on the petioles. 



Preliminary Sketch of the Action of the Several Parts, and 

 of the Manner in which Insects are Captured. 



If a small organic or inorganic object be placed on the 

 glands in the centre of a leaf, these transmit a motor impulse 

 to the marginal tentacles. The nearer ones are first affected 

 and slowly bend towards the centre, and then those farther 

 off, until at last all become closely inflected over the object. 

 This takes place in from one hour to four or five or more 



Nitschke has elaborately de- ' Trans. R. Mlcroscop. Soc' Jan. 

 scribed and figured these piiplllfe, 1876. F. D.] 



* Bot. Zeltung,' 181, pp. 234, 233, MWIth regard to the nggre- 



254. [See also A. W. Bennett, gated masses, aee p. 34, footnute. 



F. D.] 



