Whether the invasion of the territory of the solemn by the jocose results in a barely mastered impulse to laugh, depends on variable conditions. The frivolous mind, hardly touched by the gravity of the occasion, will, no doubt, often be the first to welcome the delivering hand. Yet it is an error to suppose that a tendency to laugh on a solemn occasion shows want of genuine emotion. The sincerest worshipper in a church may, if he have the requisite sensibility, be moved to laughter by some grotesque incident, such as the _mal à propos_ remark of a garrulous child. For the point of our theory is that laughter in such cases is an escape from pressure; and the man who feels deeply at such a moment may experience an emotional pressure which equals, if it does not exceed, that of the external constraint which the non-reverent “worshipper” is experiencing. It is true, of course, that the deeper the feeling the greater the inertia that will have to be overcome before the laughing impulse can make way for itself. Yet here, again, we must remember that emotional temperaments vary, and that with some a genuine awe and even an intense grief may yield now and again for a moment to the challenge of the laughable when its note catches the ear. The last remarks suggest that in any attempt to deal with the conditions favourable to laughter reference should be made to those physiological characteristics which are supposed to determine the particular temperament of a man: his special bent, say, towards jollity on the one hand, or towards a brooding melancholy on the other. Our forefathers had pretty definite ideas about the sort of bodily constitution which was the foundation of the {81} laughter-loving temper. A full “habit” tending to obesity, as in Falstaff, was, and is, I believe, popularly supposed to be a mainstay of the laughing spirit. The saying “Laugh and grow fat” may imply a vague apprehension of this relation, as well as a recognition of the benefits of laughter. Yet the precise organic substrate of this happy endowment is unknown. Health and all that makes for “good spirits” are no doubt favourable to a voluble laughter of the elemental kind. On the other hand, as we shall see, the laughing capacity frequently co-exists with physiological conditions of quite another kind. Men are to be found of a lean habit, and with a strong bent to grave reflection, who are nevertheless able, not merely to provoke laughter from others, like the “melancholy Jaques,” but themselves to contribute a sonorous laughter to the higher intellectual domains of mirth. It is conceivable that the disposition to laugh may have its own restricted physiological conditions in a special instability of the mechanism concerned. This again may presumably include some as yet undefinable property of the nerve-centres which favours rapid change in the mode of brain activity, and those sudden collapses of tension which seem to be the immediate