[21] Bergeon, as quoted in the `Journal of Anatomy
and Physiology,' Nov. 1871, p. 235.
[22] See, for instance, a case given by Sir Charles Bell,
`Philosophical Transactions,' 1823, p. 177.
As soon as by this, or by some other means, a reflex action
of this nature had been established and rendered easy,
other stimulants applied to the surface of the eye--such as a
cold wind, slow inflammatory action, or a blow on the eyelids--
would cause a copious secretion of tears, as we know to be the case.
The glands are also excited into action through the irritation
of adjoining parts. Thus when the nostrils are irritated by
pungent vapours, though the eyelids may be kept firmly closed,
tears are copiously secreted; and this likewise follows from
a blow on the nose, for instance from a boxing-glove. A stinging
switch on the face produces, as I have seen, the same effect.
In these latter cases the secretion of tears is an incidental result,
and of no direct service. As all these parts of the face,
including the lacrymal glands, are supplied with branches
of the same nerve, namely, the fifth, it is in some degree
intelligible that the effects of the excitement of any one branch
should spread to the nerve-cells or roots of the other branches.
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