communicating with the cerebral hemispheres--the seat of our
consciousness and volition. In all cases there seems to exist
a profound antagonism between the same movements, as directed
by the will and by a reflex stimulant, in the force with which they
are performed and in the facility with which they are excited.
As Claude Bernard asserts, "L'influence du cerveau tend donc
a entraver les mouvements reflexes, a limiter leur force
et leur etendue."[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