294 DIONZA MUSCIPULA. Cuar. XIIL 
between the lobes, one re-expanded after two days; 
a second after seven days; and the third after nine 
days. The leaf which closed, owing to a drop of the 
solution having adhered to one of the filaments, 
opened after two days. 
I was surprised to find on two occasions that the 
heat from the rays of the sun, concentrated by a lens 
on the bases of several filaments, so that they were 
scorched and discoloured, did not cause any move- 
ment; though the leaves were active, as they closed, 
though rather slowly, when a filament on the opposite 
side was touched. On a third trial, a fresh leaf closed 
after a time, though very slowly; the rate not being 
increased by one of the filaments, which had not been 
injured, being touched. After a day these three leaves 
opened, and were fairly sensitive when the uninjured 
filaments were touched. The sudden immersion of a 
leaf into boiling water does not cause it to close. 
Judging from the analogy of Drosera, the heat in 
these several cases was too great and too suddenly 
applied. The surface of the blade is very slightly 
sensitive ; it may be freely and roughly handled, with- 
out any movement being caused. A leaf was scratched 
rather hard with a needle, but did not close; but when 
the triangular space between the three filaments on 
another leaf was similarly scratched, the lobes closed. 
They always closed when the blade or midrib was 
deeply pricked or cut. Inorganic bodies, even of large 
size, such as bits of stone, glass, &c.—or organic bodies 
not containing soluble nitrogenous matter, such as bits 
of wood, cork, moss,—or bodies containing soluble 
nitrogenous matter, if perfectly dry, such as bits of 
meat, albumen, gelatine, &c., may be long left (and 
many were tried) on the lobes, and no movement is 
excited. The result, however, is widely different, as we 
