Before we inquire into abstraction, as fixed and expressed in words,—whether such words are the complement of an actual or possible representation, or exist alone in consciousness, as complete substitutes,—it is indispensable that we should study the origin, and still more the evolution, of this new factor. Although many linguists resolutely abstain from considering the origin of speech (which is certainly, like all other genetic problems, beyond the grasp of psychology), the question is so intimately allied with that of the evolution of articulate language, allied again in itself with the progressive development of abstraction and of generalisation, that we should not be justified in withholding a brief summary of the principal hypotheses relating to this subject, while limiting ourselves to the most recent. I. Launching forth then into this region of conjecture—do we, in the first place, find among some animals, signs and means of communication which for them are the equivalents of language? In considering this point it matters little whether or no we accept the evolutionary thesis. It must not be forgotten, in fact, that the problem of the origin of speech is only a particular case of the origin of language in general: speech being but one species among several others of the _facultas signatrix_, which can only be manifested in the lower animals in its humblest form. There can be no doubt that pain, joy, love, impatience, and other emotional states are translated by proper signs, easy to determine. Our problem, however, is different; we are concerned with signs of the _intellectual_, not of the affective, life. In other words, can certain animals transmit a warning, or an order, to their fellows? Can they muster them for a co-operative act, and make themselves intelligible? Although the interpretation is necessarily open to the suspicion of anthropomorphism, it is difficult not to recognise a sort of language in certain acts of animal life. Is it _a priori_ probable that animals, which form stable and well-organised societies, should be bereft of all means of intercommunication and comprehension?