Looking back, then, to the primal source of all nervous organization, in the remote animal in which the nervous structure and action were at the crudest state of development, and remembering that there was a power of transmitting it to offspring, and that natural and sexual selection were unceasingly operating to expand and perfect it, we may trace the successive stages of its modification and growth, from the lowest to the highest, until we reach in the primeval man the highest development that it had yet attained. But throughout all its stages, from the lowest to the highest, the system of nervous organization and action is the same in kind. We do not call its manifestations or action mind, or speak of them as indicating mind, until we find it developed into a condition of some voluntary activity and power of variation, as it is in many of the animals inferior to man. But in all the animals, man included, mind is the action of the nervous organization when it evinces a superior power of variation; and we speak of the brain of such animals as the seat of mind because that organ is the source to and from which nervous action proceeds. Let me now illustrate this view by the acquisition of articulate speech and the formation of language. In many of the lower animals with which we are acquainted there is a power of uttering vocal sounds, and of understanding them when uttered by their fellows. It must have been a power possessed by those animals which were the progenitors of man in the long line of descent of one species from another. But in them it was a very limited power. It increased as the nervous organization and the vocal organs became in the successive species capable of a more varied action. The sounds of the external world impressed themselves upon the brains of the primeval men more forcibly than they did upon the brains of the other animals, and excited the nervous organization to reproduce or imitate them. Those emotions and desires which originated in the brain itself--the impressions of pain or the sensations of pleasure experienced in the nervous system--sought expression through the vocal organs. Certain sounds repeated alike by the same individual, or by numerous individuals, for a long time, became associated in their brains with certain feelings or sensations. What are called words were thus formed; which, at first, could have been nothing but the utterance of certain sounds by the vocal organs, expressing the sensations felt by the nervous organization, or the imitations of external noises. At length these vocal sounds are gathered in the memory, multiplied and systematized, and a rude language is formed. But, all the while, the first crude human language was nothing but the result of nervous action excited to greater activity than in the other animals, accompanied by nicer and more capable vocal organs and a greater power of using them. This acquisition, obtained by the primeval men, was transmitted to