"[11]
The conscious wish to perform a reflex action sometimes stops or interrupts
its performance, though the proper sensory nerves may be stimulated.
For instance, many years ago I laid a small wager with a dozen young
men that they would not sneeze if they took snuff, although they all
declared that they invariably did so; accordingly they all took a pinch,
but from wishing much to succeed, not one sneezed, though their
eyes watered, and all, without exception, had to pay me the wager.
Sir H. Holland remarks[12] that attention paid to the act of swallowing
interferes with the proper movements; from which it probably follows,
at least in part, that some persons find it so difficult to swallow a pill.
[11] "See the very interesting discussion on the whole subject
by Claude Bernard, `Tissus Vivants,' 1866, p. 353-356.
[12] `Chapters on Mental Physiology,' 1858, p. 85.
Another familiar instance of a reflex action is the involuntary
closing of the eyelids when the surface of the eye is touched.
A similar winking movement is caused when a blow is directed
towards the face; but this is an habitual and not a strictly
reflex action, as the stimulus is conveyed through the mind
and not by the excitement of a peripheral nerve.
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