VARIOUS CHANNELS OF NERVOUS DISCHARGE. 207 



has suddenly replaced ; and this increased absorption of 

 nervous energy in mental changes, involves a temporary 

 diminution of the outflow in other directions : whence the 

 pendent jaw and the relaxing grasp. 



One further observation is worth making. Among the 

 several sets of channels into which surplus feeling might bo 

 discharged, was named the nervous system of the viscera. 

 The sudden overflow of an arrested mental excitement, 

 which, as we have seen, results from a descending incon- 

 gruity, must doubtless stimulate not only the muscular sys- 

 tem, as we see it does, but also the internal organs ; the 

 heart and stomach must come in for a share of the dis- 

 charge. And thus there seems to be a good physiological 

 basis for the j^opular notion that mii'th-creating excitement 

 facilitates digestion. 



Though in doing so I go beyond the boundaries of 

 the immediate topic, I may fitly point out that the method 

 of inquiry here followed, is one which enables us to 

 •understand various phenomena besides those of laugh- 

 ter. To show the importance of pursuing it, I will in- 

 dicate the explanation it furnishes of another familiar class 

 of facts. 



All know how generally a large amount of emotion dis- 

 turbs the action of the intellect, and interferes with the 

 power of expression. A speech delivered with great 

 facility to tables and chairs, is by no means so easily deliv- 

 ered to an audience. Every schoolboy can testify that his 

 trepidation, when standing before a master, has often dis- 

 abled him from repeating a lesson which he had duly 

 learnt. In explanation of this we commonly say that the 

 attention is distracted — that the proper train of ideas is 

 broken by the intrusion of ideas that are irrelevant. But 

 the question is, in what manner does unusual emotion 

 produce this effect; and we are here supplied with a 



