At what moment in a prolonged fit of laughter the undesirable effects begin to appear, it is not easy to say. It must be remembered that a good part of what remains of modern laughter is by no means pure hilarity. There is in it from the first ejaculation something of a biting sensation, or something of a melancholy pain. Yet, waiving this and looking on what begins as genuine hilarity, we shall find that it is not so simple a matter to determine the moment when further prolongation of the exercise will be weakening rather than strengthening. The excitement of laughter, like that of wine, may in its measurements have to be adjusted to individual constitution. Among the humiliations of life may be reckoned the discovery of an inability to go on laughing at the brilliant descriptions of a caricaturist, and an experience of aching exhaustion, of flabby collapse, while others continue the exhilarating chorus. It is natural to look on the tears which often accompany boisterous laughter as an unfavourable symptom. Things which do us good should not, we argue, make us cry. Yet {38} we may reflect that men have been known to cry out of sheer happiness. With some laughers, too, the moisture may come at an earlier stage than with others. Was Shakespeare, one wonders, thinking of a violent laughter when he made Iachimo tell Imogen that her lord Leonatus had mocked the French lover’s lugubrious despondencies “with his eyes in flood with laughter”? Perhaps in Shakespeare’s age, when laughter was held in with looser rein, the tears came more readily. According to Darwin, who has made a careful study of laughter’s tears, their appearance during a violent attack is common to all the races of mankind. He connects them with the contraction of the muscles round the eyes which has for its purpose the compressing of the gorged blood-vessels and so the protection of the eyes. This is the meaning of the tears alike in the case of grief and of extravagant mirth. The paroxysm of excessive laughter thus approaches the other extreme of violent grief; and this fact, Darwin thinks, may help us to understand how it is that hysterical patients and children often laugh and cry alternately.[22]