It would, however, be presumption to see in every instance of dramatic thought-communication a rudiment of an old and primitive language. There are many causes which favour the adaptation and elaboration of mimic language even after a system of phonetic signs has been established. In a passage which has already been quoted Mr. Roth observes that pantomimic ideograms must be very advantageous “on the war-path or the chase, where silence is so essential an adjunct to success.”[185] Another reason still more important is the fact that pantomimic action can be understood by people who speak different languages. Among civilised nations we may find many instances of the high state of development which gesture-language has attained in border countries where different peoples must necessarily often meet.[186] And it is significant that among primitive tribes gestures and motions are nowhere so full of significance and intellectual expressiveness as on the plains of Australia,[187] among the savages in the interior parts of Brazil,[188] and on the great prairies of North America,[189]—in a word, in countries where the breaking up of a nation into small vagrant tribes has been the cause of an extreme dialectical disseverance. Under these conditions, however, the impulsive, self-interpreting pantomime is apt to develop gradually into an elaborate system of conventional signs. The gesture-language of the North American Indians, for example, which consists almost entirely of abbreviated “moves” of indication and delineation, is no doubt eminently adapted to fulfil the practical requirements of comprehensibility and explicitness. But it has not much to do with dramatic art in any sense of the word. Of a more immediate importance for art-history are the pantomimics which accompany public speaking. In a state of society where every member is entitled to take part in the common deliberations, oral language will often prove an inadequate vehicle of thought. Only through displaying his speech in action is the chief or the priest capable of making its purport comprehensible to the large audiences at a popular meeting. Rhetoric, therefore, is still among many primitive tribes what it used to be in classical antiquity—a dramatic as well as a literary art.[190]