Cuar, XIUI.] SENSITIVENESS OF FILAMENTS. 235 
same solution, the fluid within the basal cells became almost. 
instantly aggregated into purplish or colourless, irregularly 
shaped masses of matter. The process of aggregation grad- 
ually travelled up the filaments from cell to cell to their ex- 
tremities, thatis in a reverse course to what occurs in the ten- 
tacles of Drosera when their glands have been excited. Several 
other filaments were cut off close to their bases, and left for 
1hr. 30 m.in a weaker solution of one part of the carbonate to 
218 of water, and this caused aggregation in all the cells, 
commencing as before at the bases of the filaments. 
Long immersion of the filaments in distilled water likewise 
causes aggregation. Nor is it rare to find the contents of 
a few of the terminal cells in a spontaneously aggregated 
condition. The aggregated 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 Dionza behave exactly like the tentacles of Drosera. 
Notwithstanding this similarity there is one remarkable 
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 produced by touching the filaments of 
Dionæa ; I compared, 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 
* [C. De Candolle (‘Archives des late the leaf, but that it may be made 
Sc. Phys. et Nat.’ Geneva, April 1876) to close by a current of water directed 
states that drops of water which in- at right angles to the filament.— 
fringe on the filaments in the direc- F, D.J 
tion of their length do not stimu- 
