Nothing in itself is more baseless than the idea that oral language is necessary for the expression of abstract ideas. The case of deaf-mutes, who without the aid of speech can give expression to the most complicated ideas, affords an example of this in the midst of a civilized society. The study of gesture-language enables us to see how easy and natural is the process by which the expression of abstract ideas grows out of the imitation of concrete objects. Take the very word to ‘grow’. An Indian expresses the notion of a tree by holding the right hand before his body, back forwards, with the fingers spread out--the fingers, as it were, representing branches, and his wrist the trunk; to show that it is high he pushes it slightly upwards. For grass he holds his hand with the fingers upwards in the sense of blades, near the ground. In order to express the general idea ‘to grow’ he begins as in the sign for grass, but instead of keeping his hand near the ground, pushes it upward in an uninterrupted manner.[15] So, too, to express falsehood he places his index and second fingers so that they separate in front of his mouth, in order to indicate a double tongue. For truth he places his index finger only in front, to show, if we may use the expression, that he is ‘single-tongued’. Root elements of gesture language, which as a means of communication preceded the development of articulate language as opposed to mere emotional cries, seem themselves to be almost universal. And picture-writing--the sister mode of expression--has also, as we see from the example of the American Continent, even in some of its more conventional developments, an immeasurably wider currency than the comparatively recent growths of oral communication. In China, amongst a great variety of mutually unintelligible languages and dialects, the ideographic characters, which are really conventionalized pictures, and independent of oral equivalents, supply to a great extent the place both of gesture and spoken language. The Red Indian world, as we have seen, is a Babel of disconnected languages, but the old sign-language is the same, and the picture-language of one tribe is generally intelligible to another.