Tears may be considered as the natural and involuntary resource of the mind overcome by some sudden and violent emotion, before it has had time to reconcile its feelings to the change of circumstances: while laughter may be defined to be the same sort of convulsive and involuntary movement, occasioned by mere surprise or contrast (in the absence of any more serious emotion), before it has time to reconcile its belief to contradictory appearances. If we hold a mask before our face, and approach a child with this disguise on, it will at first, from the oddity and incongruity of the appearance, be inclined to laugh; if we go nearer to it, steadily, and without saying a word, it will begin to be alarmed, and be half inclined to cry: if we suddenly take off the mask, it will recover from its fears, and burst out a-laughing; but if, instead of presenting the old well-known countenance, we have concealed a satyr’s head or some frightful caricature behind the first mask, the suddenness of the change will not in this case be a source of merriment to it, but will convert its surprise into an agony of consternation, and will make it scream out for help, even though it may be convinced that the whole is a trick at bottom. The alternation of tears and laughter, in this little episode in common life, depends almost entirely on the greater or less degree of interest attached to the different changes of appearance. The mere suddenness of the transition, the mere baulking our expectations, and turning them abruptly into another channel, seems to give additional liveliness and gaiety to the animal spirits; but the instant the change is not only sudden, but threatens serious consequences, or calls up the shape of danger, terror supersedes our disposition to mirth, and laughter gives place to tears. It is usual to play with infants, and make them laugh by clapping your hands suddenly before them; but if you clap your hands too loud, or too near their sight, their countenances immediately change, and they hide them in the nurse’s arms. Or suppose the same child, grown up a little older, comes to a place, expecting to meet a person it is particularly fond of, and does not find that person there, its countenance suddenly falls, its lips begin to quiver, its cheek turns pale, its eye glistens, and it vents its little sorrow (grown too big to be concealed) in a flood of tears. Again, if the child meets the same person unexpectedly after long absence, the same effect will be produced by an excess of joy, with different accompaniments; that is, the surprise and the emotion excited will make the blood come into his face, his eyes sparkle, his tongue falter or be mute, but in either case the tears will gush to his relief, and lighten the pressure about his heart. On the other hand, if a child is playing at hide-and-seek, or blindman’s-buff, with persons it is ever so fond of, and either misses them where it had made sure of finding them, or suddenly runs up against