Cnar. XVI. MOVEMENTS OF THE LEAVES. 871 
doubt that it profits by its power of digesting and 
absorbing matter from the prey which it habitually cap- 
tures in such large numbers. It will, however, be con- 
venient first to describe the movements of the leaves. 
Movements of the Leaves.—That such thick, large leaves 
as those of Pinguicula vulgaris should have the power 
of curving inwards when excited has never even been 
suspected. It is necessary to select for experiment 
leaves with their glands secreting freely, and which 
have been prevented from capturing many insects; as 
old leaves, at least those growing in a state of nature, 
have their margins already curled so much inwards 
that they exhibit little power of movement, or move 
very slowly. I will first give in detail the more 
important experiments which were tried, and then 
make some concluding remarks. 
Experiment 1.—A young and almost upright leaf was selected, 
with its two lateral edges equally and very slightly incurved. 
A row of small flies was placed along one 
margin. When looked at next day, after 
15 hrs., this margin, but not the other, was 
found folded inwards, like the helix of the 
human ear, to the breadth of y, of an 
inch, so as to lie partly over the row of 
flies (fig. 15). The glands on which the 
flies rested, as well as those on the over- 
lapping margin which had been brought 4 
into contact with the flies, were all secreting 
copiously. 
Experiment 2.—A row of flies was placed 
on ove margin of a rather old leaf, which * 
lay flat on the ground; and in this case 
the margin, after the same interval as be- 
fore, namely 15 hrs., had only just begun ers : 
to curl inwards; but so much secretion (’imgutcula vulgaris.) 
had been poured forth that the spoon- eee ee ee 
shaped tip of the leaf was filled with it. row of small flies, 
Experiment 3,—Fragments of a large fly were placed close ta 
the apex of a vigorous leaf, as well as along half one margin. 
Fic, 15. 
