We may now pass to the larger experience of the audible laugh. That this action is physiologically continuous with {28} the smile has already been suggested. The facial expression is approximately the same in the broad smile and the gentle laugh. It is only when laughter grows immoderate that there is a marked addition of other features, _viz._, the strong contraction of the muscles about the eyes leading to frowning, and the shedding of tears. How closely connected are smiling and moderate laughing may be seen by the tendency we experience when we reach the broad smile and the fully open mouth to start the respiratory movements of laughter. As Darwin and others have pointed out, there is a series of gradations from the faintest and most decorous smile up to the full explosion of the laugh.[13] One may, perhaps, go farther and say that the series of gradations here indicated is gone through, more or less rapidly, in an ordinary laugh. Persons who laugh slowly, finding it difficult to “let themselves go,” can be seen to pass through these stages. It has been said by an ingenious American inquirer that laughter may begin either with the eyes or with the mouth, the frequency of the former mode, as compared with the latter, in the instances examined being as 7 to 5.[14] It may be added that, to this continuity of form in the actions of smiling and laughing, there answers a community of function. As will be shown more fully by-and-by, both are in their primitive forms manifestations of pleasure, laughter being primarily the expression of the fuller measures of the happy or gladsome state, and varying in energy and volume with the degree of this fulness. The chronological relations of the reign of the smile and the laugh in the life of the individual will occupy us {29} presently. Here it may be enough to say that these relations allow us to think of smiling at once as the precursor and as the successor of her kinsman. The first smiles are a step away from the exceeding gravity of baby-hood towards full hilarity, the last are a step back from this hilarity to the stolid composure of senile infancy. It would seem to follow that the sharp distinction often drawn between smiling and laughing is artificial. Society, led by its Chesterfield, may emphasise the difference between the incipient and the completed process, allowing the one and forbidding the other; but the natural man is inclined to regard them as one.