Laughter a Series of Barks

1909

Laughing is barking, say the scientists. The neck and head are thrown back while a series of short barks are emitted from the throat. However musical the barks may be, they are barks.

The laugh begins with a sudden and violent contraction of the muscles of the chest and abdomen. But instead of opening to let the air pass out of the lungs, the vocal cords approach each other and hold it back. But they are not strong enough to exercise such opposition for more than an instant, and the air, which is under pressure, promptly escapes. As it does so it makes the vocal cords vibrate producing the bark.

This obstruction and liberation of the air expelled from the lungs repeats itself again and again at intervals of a quarter of a second. There are thus in a hearty laugh four barks a second, and if continued, they go on at that rate as long as the air reserve in the lungs holds out. The empty lungs must then fill themselves, and this interval is marked by a quick gasp for breath, after which the barks are renewed. The barks occur in series with gasps for breath at intervals.

When laughter is violent, the entire body participates. The upper part of the trunk bends and straightens itself alternately or sways to right and left. The feet stamp on the floor, while the hands are pressed upon the loins to moderate the painful spasm.