372 PINGUICULA VULGARIS. Cuar. XVL 
After 4 hrs. 20 m. there was decided incurvation, which in- 
creased a little during the afternoon, but was in the same state 
on the following morning. Near the apex both margins were 
inwardly curved. I have never seen a case of the apex itself 
being in the least curved towards the base of the leaf. After 
48 hrs. (always reckoning from the time when the flies were 
placed on the leaf) the margin had everywhere begun to unfold. 
Experiment 4.—A large fragment of a fly was placed on a leaf, 
in a medial line, a little beneath the apex. Both lateral mar- 
gins wore perceptibly incurved in 3 hrs., and after 4 hrs. 20 m. 
to such a degree that the fragment was clasped by both margins. 
After 24 hrs. the two infolded edges near the apex (for the lower 
part of the leaf was not at all affected) were measured and 
found to be ‘11 of an inch (2°795 mm.) apart. The fly was now 
removed, and a stream of water poured over the leaf so as to 
wash the surface; and after 24 hrs. the margins were ‘25 of an 
inch (6349 mm.) apart, so that they were largely unfolded. After 
an additional 24 hrs. they were completely unfolded. Another 
fly was now put on the same spot to see whether this leaf, on 
which the first fly had been left 24 hrs., would move again; 
after 10 hrs. there was a trace of incurvation, but this did not 
increase during the next 24 hrs. A bit of meat was also placed 
on the margin of a leaf, which four days previously had become 
strongly incurved over a fragment of a fly and had afterwards 
re-expanded; but the meat did not cause even a trace of incur- 
vation. On the contrary, the margin became somewhat reflexed, 
as if injured, and so remained for the three following days, as 
long as it was observed. 
Experiment 5.—A large fragment of a fly was placed halfway 
between the apex and base of a leaf and halfway between the 
midrib and one margin. A short space of this margin, opposite 
the fly, showed a trace of incurvation after 3 hrs., and this 
became strongly pronounced in 7 hrs. After 24 hrs. the infolded 
edge was only ‘16 of an inch (4064 mm.) from the midrib. 
The margin now began to unfold, though the fly was left on the 
leaf; so that by the next morning (ie. 48 hrs. from the time 
when the fly was first put on) the infolded edge had almost 
completely recovered its original position, being now ‘3 of an 
inch (7°62 mm.), instead of -16 of an inch, from the midrib. 
A trace of flexure was, however, still visible. 
Experiment 6.—A young and concave leaf was selected with 
its margins slightly and naturally incurved. Two rather large, 
oblong, rectangular pieces of roast meat were placed with their 
ends touching the infolded edge, and ‘46 of an inch (11°68 mm.) 
