Parallel with this mental process the articulation of sounds is gradually becoming perfected. The finer sense detects the differences of them, and begins, first to agglomerate, then to distinguish them. Times, persons, places, relations of all kinds, are expressed by modifications of them. The earliest parts of speech, as we may call them by anticipation, like the first utterances of children, probably partook of the nature of interjections and nouns; then came verbs; at length the whole sentence appeared, and rhythm and metre followed. Each stage in the progress of language was accompanied by some corresponding stage in the mind and civilisation of man. In time, when the family became a nation, the wild growth of dialects passed into a language. Then arose poetry and literature. We can hardly realize to ourselves how much with each improvement of language the powers of the human mind were enlarged; how the inner world took the place of outer; how the pictorial or symbolical or analogical word was refined into a notion; how language, fair and large and free, was at last complete. So we may imagine the speech of man to have begun as with the cries of animals, or the stammering lips of children, and to have attained by degrees the perfection of Homer and Plato. Yet we are far from saying that this or any other theory of language is proved by facts. It is not difficult to form an hypothesis which by a series of imaginary transitions will bridge over the chasm which separates man from the animals. Differences of kind may often be thus resolved into differences of degree. But we must not assume that we have in this way discovered the true account of them. Through what struggles the harmonious use of the organs of speech was acquired; to what extent the conditions of human life were different; how far the genius of individuals may have contributed to the discovery of this as of the other arts, we cannot say: Only we seem to see that language is as much the creation of the ear as of the tongue, and the expression of a movement stirring the hearts not of one man only but of many, “as the trees of the wood are stirred by the wind.” The theory is consistent or not inconsistent with our own mental experience, and throws some degree of light upon a dark corner of the human mind.