CUAK XIII. SENSITIVENESS OF FILAMENTS. 291 



masses undergo incessant slow changes of form, uniting 

 and again separating ; and some of them apparently 

 revolve round their own axes. A current of colourless 

 granular protoplasm could also be seen travelling 

 round the walls of the cells. This current ceases to 

 be visible as soon as the contents are well aggregated ; 

 but it probably still continues, though no longer 

 visible, owing to all the granules in the flowing layer 

 having become united with the central masses. In all 

 these respects the filaments of Diontea behave exactly 

 like the tentacles of Drosera. 



Notwithstanding this similarity there is one re- 

 markable difference. The tentacles of Drosera, after 

 their glands have been repeatedly touched, or a particle 

 of any kind has been placed on them, become inflected 

 and strongly aggregated. No such effect is pro- 

 duced by touching the filaments of Dionoea ; I com- 

 pared, after an hour or two, some which had been 

 touched and some which had not, and others after 

 twenty-five hours, and there was no difference in the 

 contents of the cells. The leaves were kept open all 

 the time by clips ; so that the filaments were not 

 pressed against the opposite lobe. 



Drops of water, or a thin broken stream, falling 

 from a height on the filaments, did not cause the 

 blades to close ; though these filaments were afterwards 

 proved to be highly sensitive. No doubt, as in the 

 case of Drosera, the plant is indifferent to the heaviest 

 shower of rain. Drops of a solution of a half an ounce 

 of sugar to a fluid ounce of water were repeatedly 

 allowed to fall from a height on the filaments, but 

 produced no effect, unless they adhered to them. 

 Again, I blew many times through a fine pointed 

 tube with niy utmost force against the filaments 

 without any effect; such blowing being received 



