Laughter is like a windshield wiper, it doesn't stop the rain but allows us to keep going.

An interior convulsion, producing a distortion of the features and accompanied by inarticulate noises. It is infectious and, though intermittent, incurable. Liability to attacks of laughter is one of the characteristics distinguishing man from the animals-- these being not only inaccessible to the provocation of his example, but impregnable to the microbes having original jurisdiction in bestowal of the disease. Whether laughter could be imparted to animals by inoculation from the human patient is a question that has not been answered by experimentation. Dr. Meir Witchell holds that the infection character of laughter is due to the instantaneous fermentation of _sputa_ diffused in a spray. From this peculiarity he names the disorder _Convulsio spargens_.