The ancients associated laughter with the New Year. I am not sure whether or no it is of good omen to begin the New Year with laughter. Omens are such tricky things that I have given up paying any attention to them. One would think it might be held to be unlucky to stumble 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."