communication of thought might be carried out to a great extent if found advantageous to the species. Expression of this kind arises from the need for an outlet through which the nervous disturbance caused by the impression of the object may be discharged. The action is propagated from the nervous centres which have been disturbed by the impression, and spends itself partly in working the organs of utterance, and partly on the sensations which their action produces. The disturbance is thus diffused, and the original seats of it recover their equilibrium more easily. And no doubt the expression of thought in human speech has a similar origin. The thoughts which were expressed originally, involved a cerebral disturbance which needed an outlet for its discharge, and the readiest outlet was audible utterance. Afterwards the pleasures and advantages of communicating thought would stimulate expression and prompt an effort to imitate the thought in the sensations of the utterance, and promote the development of language. But there is no reason to think that its original source was different from that of audible expression amongst the lower animals. Now if this be so, the peculiarity of human speech is, that it gives expression to such fine elements of thought without being moved by the force of any other associated emotion except the pleasure or utility of expressing them. The conceptions of facts are broken into their constituent parts, and these elements, though so fine, are yet thought with such development of cerebral force that its discharge produces audible utterance to relieve the interest of the thought by imparting it. The nerve force which is expended in such utterance, with its accompanying sensations, is an approximate measure of the cerebral energy engaged in the thought which is expressed. And what language reveals as man's peculiarity is the amount of his cerebral energy. This peculiarity in man is plainly indicated by the development of his brain and by the proportion of his blood which goes to sustain its action and nutrition. And such vastly superior cerebral energy in man compared with the lower animals implies that their intelligence consists of little more than mere rudiments of his thoughts. A difference in kind separates human thought from the intelligence of those animals which cannot think fact or general principle. And even the highest of the mammalia below man seem to have only the beginnings of the latter. So that even from their intelligence human thought is broadly distinguished by the full apprehension of general principles which is involved in the power of reasoning and in the very ideas of causation, of the constitution and properties of things, and of the moral law. THE END. PRINTED BY BALLANTYNE, HANSON AND CO. |