owing to his superior faculties in this respect that he holds his place
so high above the rest of creation. Orators, who make it their study to
be impressive, give full importance to every kind of expression, and say
that a man should be able to make his meaning understood, even when his
voice is inaudible. It has been lately discovered that the mere movement
of the lips alone, without sound, is sufficient to convey
information.[2] Facial expression has been given us as a means of
assisting communication, and smiles and laughter have become the
distinctive manifestations of humour. Thus the electric spark passes
from one to another, and the flashing eye and wreathed lip lights up the
world. Profit also accrues--fear of being laughed at leads us to avoid
numerous small errors, and by laughing at others we are enabled to
detect shortcomings in ourselves.

Sympathetic laughter does not arise from any contemplation of ludicrous
circumstances, but is only a sort of reflection of the feelings of
others. There seems to be little intelligence in it, but something
almost physical, just as yawning is infectious, or as on seeing a person
wounded in a limb we instinctively shrink ourselves in the same part of
the body. Even a picture of a man laughing will have some effect upon
us, and so have those songs in which exuberant mirth is imitated. Thus
we often laugh without feeling just cause, as we often feel cause
without laughing. All exhibitions of emotion are infectious. We feel sad
at seeing a man in grief, although the source of his sorrow is unknown
to us; and we are inclined to be joyous when surrounded by the votaries
of mirth. Not unfrequently we find a number of persons laughing, when
the greater part of them have no idea what is the cause of the
merriment. Sometimes we cannot entirely resist the impulse, even when we
ourselves are the object of it, so much are we inclined to enter into
the feelings and views of those who surround us. In this, as well as in