302 PINGUICULA VULGARIS. [Cuap. XVI 
inch (2°54 mm.) from the edges; or about a quarter of the distance 
between the edge and midrib. A third bit of sponge adhered to the 
edge, and, as the margin unfolded, was dragged backwards, into its 
original position. 
Experiment 9.—A chain of fibres of roast meat, as thin as bristles 
and moistened with saliva, were placed down one whole side, close to 
the narrow, naturally incurved edge of a leaf. In 3 hrs. this side was 
greatly incurved along its whole length, and after 8 hrs. formed a 
cylinder, about 3, of an inch (1°27 mm.) in diameter, quite concealing 
the meat. This cylinder remained closed for 32 hrs., but after 48 hrs. 
was half unfolded, and in 72 hrs. was as open as the opposite margin 
where no meat had been placed. As the thin fibres of meat were 
completely overlapped by the margin, they were not pushed at all 
inwards, across the blade. 
Experiment 10.—Six cabbage seeds, soaked for a night in water, 
were placed in a row close to the narrow incurved edge of a leaf. We 
shall hereafter see that these seeds yield soluble matter to the glands. 
In 2 hrs. 25 m. the margin was decidedly inflected; in 4 hrs. it 
extended over the seeds for about half their breadth, and in 7 hrs. over 
three-fourths of their breadth, forming a cylinder not quite closed 
along the inner side. After, 24 hrs. the inflection had not increased, 
perhaps had decreased. The glands which had been brought into 
contact with the upper surfaces of the sceds. were now secreting freely. 
In 36 hrs. from the time when the seeds were put on the leaf the 
margin had greatly, and after 48 hrs. had completely, re-expanded. 
As the seeds were no longer held by the inflected margin, and as the 
secretion was beginning to fail, they rolled some way down the 
marginal channel. 
Experiment 11.—Fragments of glass were placed on the margins of 
two fine young leaves. After 2 hrs. 30 m. the margin of one certainly 
became slightly incurved; but the inflection never increased, and dis- 
appeared in 16 hrs. 30 m. from the time when the fragments were 
first applied. With the second leaf there was a trace of incurvation 
in 2 hrs. 15 m., which became decided in 4 hrs. 30 m., and still more 
strongly pronounced in 7 hrs., but after 19 hrs. 30 m. had plainly 
decreased. The fragments excited at most a slight and doubtful in- 
crease of the secretion; and in two other trials, no increase could be 
perceived. Bits of coal-cinders, placed on a leaf, produced no effect, 
either owing to their lightness or to the leaf being torpid. : 
Experiment 12.—We will now turn to fluids. A row of drops of a 
strong infusion of raw meat were placed along the margins of two 
leaves; squares of sponge soaked in the same infusion being placed on 
the opposite margins. My object was to ascertain whether a fluid 
would act as energetically as a substance yielding the same soluble 
matter to the glands. No distinct difference was perceptible; certainly 
none in the degree of incurvation; but the incurvation round the bits 
of sponge lasted rather longer, as might perhaps have been expected 
from the sponge remaining damp and supplying nitrogenous matter 
