umble on
the doorstep as you set out from home, but the old omen-wizards,
apparently from sheer love of contradiction, said, "Not at all! It is
unlucky to stumble as you come into the house, and therefore it is
lucky to stumble as you go out!"

What is laughter? It is a spasmodic movement of various muscles of the
body, beginning with those which half close the eyes and those which
draw backwards and upwards the sides of the mouth, and open it so as
to expose the teeth, next affecting those of respiration so as to
produce short rapidly succeeding expirations accompanied by sound
(called "guffaws" when in excess) and then extending to the limbs,
causing up and down movement of the half-closed fists and stamping of
the feet, and ending in a rolling on the ground and various
contortions of the body. Clapping the hands is not part of the
laughter "process," but a separate, often involuntary, action which
has the calling of attention to oneself as its explanation, just as
slapping the ground or a table or one's thigh has. Laughter is
spontaneous, that is to say, the movements are not designed or
directed by the conscious will. But in mankind, in proportion as
individuals are trained in self-control, it is more or less completely
under command, and in spite of the most urgent tendency of the
automatic mechanism to enter upon the progressive series of movements
which we distinguish as (1) smile, (2) broad smile or grin, (3)
laugh, (4) loud laughter, (5) paroxysms of uncontrolled laughter, a
man or woman can prevent all indication by muscular movement of a
desire to laugh or even to smile. Usually laughter is excited by
certain pleasurable emotions, and is to be regarded as an "expression"
of such emotion just as certain movements and the flow of tears are an
"expression" of the painful emotion of grief and physical suffering,
and as other movements of the face and limbs are an "expression" of
anger, others of "fear." The Greek gods of Olympus enjoyed
"inextinguishable laughter."

It is interesting to see how far we can account for the strange
movements of laughter as part of the inherited automatic mechanism of
man. Why do we laugh? What is the advantage to the individual or the
species of "laughing"? Why do we "express" our pleasurable emotion and
why in this way? It is said that the outcast diminutive race of Ceylon
known as the Veddas never laugh, and it has even been seriously but
erroneously stated that the muscles whi