case has been recorded. But a mere sense of discomfort would
probably suffice to lead to the associated habit of protecting
the eyeball by the contraction of the surrounding muscles.
Even the expectation or chance of injury would probably
be sufficient, in the same manner as an object moving too
near the eye induces involuntary winking of the eyelids.
We may, therefore, safely conclude from Sir C. Bell's observations,
and more especially from the more careful investigations
by Professor Donders, that the firm closure of the eyelids
during the screaming of children is an action full of meaning
and of real service.

We have already seen that the contraction of the orbicular muscles
leads to the drawing up of the upper lip, and consequently,
if the mouth is kept widely open, to the drawing down of
the corners by the contraction of the depressor muscles.
The formation of the naso-labial fold on the cheeks likewise
follows from the drawing up of the upper lip. Thus all the chief
expressive movements of the face during crying apparently
result from the contraction of the muscles round the eyes.
We shall also find that the shedding of tears depends on,
or at least stands in some connection with, the contraction
of these same muscles.


[17] Donders, ibid. p. 36.

In some of the foregoing cases, especially in those of sneezing and coughing,
it is possible that the contraction of the orbicular muscles may serve
in addition to protect the eyes from too severe a jar or vibration.