One other social aspect of laughter illustrated by savage life needs to be touched on. In the instinctive tendency of the savage to ridicule the customs and ideas of outside folk we have one expression of the self-protective attitude of a {257} community against insidious outside influences. Just as the Hebrews ridiculed the religious ideas of the worshippers of Baal and so helped to keep their national faith intact, so these tribes low down in the culture scale have in their laughter at what is foreign a prophylactic against any contamination from outside peoples. No doubt this tendency in laughter will help to preserve once useful tribal characters when altered circumstances, introduced, for example, by the coming of the white man, require new adaptations. In this we see the essentially conservative function of laughter in the life of societies. On the other hand, as we have seen, novelties in dress introduced by the white man may attract and delight. In dealing with the connection between social progress and laughter, we shall need to consider very carefully the attitude which the mirthful spirit takes up towards social changes. Now these aspects of laughter point, as we have seen, to a social utility in laughter. As offspring of the play-impulse, it might, indeed, be expected to share in those benefits which, as recent research has made clear, belong to play. In our study of its development and persistence in the life of progressive communities, we shall have occasion to illustrate this utility much more fully. That laughing is good, physically and morally, for its individual subjects has become a commonplace, at least to the student of literature. Here we shall be concerned with its distinctly social advantages, such as the maintenance of customs which from the point of view of the community, or of some class of the community, are to be regarded as good, the keeping down of vices and follies, and the furtherance of social co-operation. The question how far this utility extends is one which cannot be answered simply. It will be found that societies, {258} so far from universally recognising laughter as a useful habit, have taken vast pains to restrain it. Indeed, our study of the fortunes of mirth in the advance of social life will show us that it has had throughout to struggle for its existence.