156 TENDRIL-BEARERS. Cuapr. IV. 
I repeated the experiment made on the Echinocystis, 
and placed several plants of this Passiflora so close 
together, that their tendrils were repeatedly dragged 
over each other; but no curvature ensued. I likewise 
repeatedly flirted small drops of water from a brush on 
many tendrils, and syringed others so violently that 
the whole tendril was dashed about, but they never 
became curved. The impact from the drops of water 
was felt far more distinctly on my hand than that from 
the loops of thread (weighing nd of a grain) when 
allowed to fall on it from a height, and these loops, 
which caused the tendrils to become curved, had been 
placed most gently on them. Hence it is clear, that the 
tendrils either have become habituated to the touch of 
other tendrils and drops of rain, or that they were from 
the first rendered ‘sensitive only to prolonged though 
excessively slight pressure of solid objects, with the 
exclusion of that from other tendrils. To show the 
difference in the kind of sensitiveness in different plants 
and likewise to show the force of the syringe used, I 
may add that the lightest jet from it instantly caused 
the leaves of a Mimosa to close; whereas the loop of 
thread weighing sind of a grain, when rolled into a 
ball and placed gently on the glands at the bases of 
the leaflets of the Mimosa, caused no action. 
Passiflora punctata.—The internodes do not move, 
but the tendrils revolve regularly. A half-grown and 
very sensitive tendril made three revolutions, opposed 
to the course of the sun, in 3hrs. 5m., 2 hrs. 40m., 
and 2 hrs. 50m.; perhaps it might have travelled more 
