200 THE PHYSIOLOGY OF LAUGIITEK. 



mcnt is at once arrested. From the viscera, too, intense 

 mental action abstracts energy. Joy, disappointment, anx 

 iety, or any moral perturbation rising to a great height, 

 will destroy appetite ; or if food has been taken, will arrest 

 digestion ; and even a purely intellectual activity, when 

 extreme, will do the like. 



Facts, then, fully bear out these d priori inferences, 

 that the nervous excitement at any moment present to 

 consciousness as feeling, must expend itself in some way or 

 other ; that of the three classes of channels open to it, it 

 must take one, two, or more, according to circumstances ; 

 that the closure or obstruction of one, must increase the 

 discharge through the others ; and conversely, that if to 

 answer some demand, the cfHux of nervous energy in one 

 direction is unusually great, there must be a corresponding 

 decrease of the efllux in other directions. Setting out 

 from these premises, let us now see what interpretation i.s 

 to be put on the phenomena of laughter. 



That laughter is a display of muscular excitement, and 

 so illustrates the general law that feeling passing a certain 

 pitch habitually vents itself in bodily action, scarcely needs 

 pointing out. It perhaps needs pointing out, however, 

 that strong feeling of almost any kind produces this result. 

 It is not a sense of the ludicrous, only, which does it ; nor 

 arc the various forms of joyous emotion the sole additional 

 causes. We have, besides, the sardonic laughter and the 

 hysterical laughter, Avhich result from mental distress ; to 

 which must be added certain sensations, as tickling, and, 

 according to Mr. Bain, cold, and some kinds of acute pain. 



Strong feeling, mental or physical, being, then, the gen 

 eral cause of laughter, we have to note that the muscular 

 actions constituting it are distinguished from most others 



o o 



by this, that they are purposeless. In general, bodily mo 

 tions that are prompted by feelings arc directed to special 



