Immersion in sulphuric ether for 24 hrs. loosened them much, but
warmed essential oils (I tried oil of thyme and peppermint)
completely released every particle of stone in the course of a few
hours. This seems to prove that some resinous cement is secreted.
The quantity, however, must be small; for when a plant ascended a
thinly whitewashed wall, the discs adhered firmly to the whitewash;
but as the cement never penetrated the thin layer, they were easily
withdrawn, together with little scales of the whitewash. It must not
be supposed that the attachment is effected exclusively by the
cement; for the cellular outgrowth completely envelopes every minute
and irregular projection, and insinuates itself into every crevice.
A tendril which has not become attached to any body, does not
contract spirally; and in course of a week or two shrinks into the
finest thread, withers and drops off. An attached tendril, on the
other hand, contracts spirally, and thus becomes highly elastic, so
that when the main foot-stalk is pulled the strain is distributed
equally between all the attached discs. For a few days after the
attachment of the discs, the tendril remains weak and brittle, but it
rapidly increases in thickness and acquires great strength.
Pages:
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191