The reasons from which Max Mueller, in his "Lectures on the Science of Languages" (Vol. I, Lect. IX), rejects the first two theories and proves the third, are quite convincing. Even if, in a purely hypothetical way, a language could be thought of _in abstracto_, the roots of which only consist in imitations of sounds or interjections, still in the _really existing_ languages, {97} so far as we can trace back and uncover their roots, the roots imitating sounds and the interjectional roots form only a small and entirely isolated minority, which neither shares in, nor is capable of development; they stand like "dead sticks in a live hedge." By far the greater number of roots, and all which are capable of development, express abstractions from visible objects, conditions and activities, and therefore presume a human intelligence, reflecting with self-consciousness, which formed and used the roots. Now Max Mueller sees, back of this period, still open to science, in which the root-elements of the human languages were fixed, a long period of exuberant and unhindered growth of the elements of language, in which the roots were separated from the multitude of nascent tones by elimination or natural selection in the struggle for existence. In this realm, which is no longer open to investigation, the naturalistic and the linguistic friends of the evolution theory are now in entire accord. Wilhelm Bleek, in his small, but very noteworthy essay, "Ueber den Ursprung der Sprache" ("Origin of Language"), Weimar, Boehlau, 1868, p. 11, uses this ingenious figure: what the animal world possesses analogous to language, takes about the same position as, in the art of printing, the block-print does in relation to printing with movable types. On page 12, he sees in the communication of the emotions among animals the sources from which under favorable conditions (in consequence of which the separation of language into articulated parts became possible) human language might have originated. This idea, which is closely joined to the interjectional theory, Darwin meets {98} with a related idea, depending upon the onomatopoetical theory, when he says, in his "Descent of Man": "Since monkeys certainly understand much that is said to them by man, and when wild, utter signal-cries of danger to their fellows, may not some unusually wise ape-like animal have imitated the growl of a beast of prey, and thus told his fellow-monkeys the nature of the expected danger? This would have been a first step in the formation of language."