198 THE PHYSIOLOGY OF LAUGHTER. 



motor nerves, and so cause muscular contractions ; or they 

 may pass on the excitement to nerves which supply the vis 

 cera, and may so stimulate one or more of these. 



For simplicity s sake, I have described these as alterna 

 tive routes, one or other of which any current of nerve- 

 force must take ; thereby, as it may be thought, implying 

 that such current will be exclusively confined to some ono 

 of them. But this is by no means the case. Ilarely, if 

 ever, docs it happen that a state of nervous tension, present 

 to consciousness as a feeling, expends itself in ono direction 

 only. Very generally it may be observed to expend itself 

 in two ; and it is probable that the discharge is never abso 

 lutely absent from any one of the three. There is, how 

 ever, variety in the jn oportiontt in which the discharge is 

 divided among these dillrrent channels under different cir 

 cumstances. In a man &quot;whose fear impels him to run, the 

 mental tension generated is only in part transformed into a 

 muscular stimulus: there is a surplus which causes a rapid 

 current of ideas. An agreeable state of feeling produced, 

 say by praise, is not wholly used up in arousing the suc 

 ceeding phase of the feeling, and the new ideas appropriate 

 to it ; but a certain portion overflows into the visceral ner 

 vous system, increasing the action of the heart, and proba 

 bly facilitating digestion. And here we come upon a class 

 of considerations and facts which open the way to a solu 

 tion of our special problem. 



For starting with the unquestionable truth, that at any 

 moment the existing quantity of liberated nerve-force, 

 which in an inscrutable way produces in us the state we 

 call feeling, intent expend itself in some direction must 

 generate an equivalent manifestation of force somewhere 

 it clearly follows that, if of the several channels it may 

 take, one is wholly or partially closed, more must be taken 

 by the others; or that if two are closed, the discharge 

 aloii&quot; 1 the remaining one must be more intense ; and that, 



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