Whatever may be the force of this reasoning, conclusive for some, doubtful for others, the conditions necessary to the existence of speech arose with articulation only, consonants being its firmest element. The origin of speech has been much disputed. Romanes invokes natural selection: “The first articulation probably consisted in nothing further than a semiotic breaking of vocal tones, in a manner resembling that which still occurs in the so-called chattering of monkeys,—the natural language for the expression of their mental states.”[48] It should, however, be noted that the question, under this form, has merely a physiological interest. The voice is as natural to man as are the movements of his limbs; between simple voice and articulate voice there is but the same distance as between the irregular movements of the limbs of the newly born, and such well-co-ordinated movements as walking. Articulation is merely one of the forms of expression: it is so little _human_ that it is met with, as we have seen, among many of the lower animals. The true _psychological_ problem lies elsewhere: in the employment of articulate sounds as _objective signs_, and the attaching of these to objects with which they are related by no natural tie. Geiger in his _Ursprung der Sprache_ (1878) brought forward a hypothesis which has been sustained by other authors. It may be summed up as follows: words are an imitation of the movements of the mouth. The predominant sense in man is that of sight; man is pre-eminently visual. Prior to the acquisition of speech, he communicated with his fellows by the aid of gestures, and movements of the mouth and face; he appealed to their eyes. Their facial “grimaces,” fulfilled and elucidated by gesture, became signs for others; they fixed their attention on them. When articulate sounds came into being, these lent themselves to a more or less conventional language by reason of their acquired importance. For support of this hypothesis, we are referred to the case of non-educated deaf-mutes. These invent articulate sounds (which of course they cannot hear), and use them to designate certain things. While many of these words appear to be an arbitrary creation (e. g., _ga_ = one, _ricke_ = I will not, etc.), others result from the imitation by their mouth of the movements perceived on the mouth of others. Such are _mumm_ = to eat; _chip_ = to drink; _be-yr_ = barking of a dog, etc.[49] Why should primitive man have done less than the deaf-mute, when he not only saw the movements but heard the sounds to boot? To conclude with a subject in which individual hypotheses abound, and which for us is only of indirect interest, we may summarise the sketch given recently enough (1888) by one of the principal partisans of the evolutionary theory: