In the weeks of natural stimulation, she had been the one who was embarrassed.
He was hungry after the stimulation of Jessi's refusal to bend to his will.
Many points in the development and mechanism of the nematocyst are disputed, but it is tolerably certain (I) that the cnidocil is of sensory nature, and that stimulation, by contact with prey or in other ways, causes a reflex discharge of the nematocyst; (2) that the discharge is an explosive change whereby the in-turned thread is suddenly everted and turned inside out, being thus shot through the opening in the outer wall of the capsule, and forced violently into the tissues of the prey, or, it may be, of an enemy; (3) that the thread inflicts not merely a mechanical wound, but instils an irritant poison, numbing and paralysing in its action.
In both these cases the stimulation is followed, not only by movement, but by the secretion of an acid liquid containing a digestive juice, by virtue of which the insect is digested after being killed.
The perception of the changes, or, in other words, the reception of the stimulus, is associated for example, with the tips of roots and the apices of stems. The first recognition of a specially receptive part was made by Charles Darwin, who identified the perception of stimulation with the tip of the young growing root.