bent inwards—­there is a slight degree of what medical men call opisthotonos.  Thus, then, without contending that the phenomena of laughter in all their details are to be so accounted for, we see that in their ensemble they conform to these general principles:—­that feeling excites to muscular action; that when the muscular action is unguided by a purpose, the muscles first affected are those which feeling most habitually stimulates; and that as the feeling to be expended increases in quantity, it excites an increasing number of muscles, in a succession determined by the relative frequency with which they respond to the regulated dictates of feeling.

There still, however, remains the question with which we set out.  The explanation here given applies only to the laughter produced by acute pleasure or pain:  it does not apply to the laughter that follows certain perceptions of incongruity.  It is an insufficient explanation that, in these cases, laughter is a result of the pleasure we take in escaping from the restraint of grave feelings.  That this is a part-cause is true.  Doubtless very often, as Mr. Bain says, “it is the coerced form of seriousness and solemnity without the reality that gives us that stiff position from which a contact with triviality or vulgarity relieves us, to our uproarious delight.”  And in so far as mirth is caused by the gush of agreeable feeling that follows the cessation of mental strain, it further illustrates the general principle above set forth.  But no explanation is thus afforded of the mirth which ensues when the short silence between the andante and allegro in one of Beethoven’s symphonies, is broken by a loud sneeze.  In this, and hosts of like cases, the mental tension is not coerced but spontaneous—­not disagreeable but agreeable; and the coming impressions to which the attention is directed, promise a gratification that few, if any, desire to escape.  Hence, when the unlucky sneeze occurs, it cannot be that the laughter of the audience is due simply to the release from an irksome attitude of mind:  some other cause must be sought.

This cause we shall arrive at by carrying our analysis a step further.  We have but to consider the quantity of feeling that exists under such circumstances, and then to ask what are the conditions that determine the direction of its discharge, to at once reach a solution.  Take a case.  You are sitting in a theatre, absorbed in the progress of an interesting drama.  Some climax has been reached which has aroused your sympathies—­say, a reconciliation between the hero and heroine, after long and painful misunderstanding.  The feelings excited by this scene are not of a kind from which you seek relief; but are, on the contrary, a grateful relief from the painful feelings with which you have witnessed the previous estrangement.  Moreover, the sentiments these fictitious personages have for the moment inspired you with, are not such as would lead you to rejoice