That the natural sciences, too, should have felt the electric shock of our new science is not surprising, considering that man is the crown of nature, the apex to which all other forces of nature point and tend. But that which makes man man, is language. _Homo animal rationale, quia orationale_, as Hobbes said. Buffon called the plant a sleeping animal; living philosophers speak of the animal as a dumb man. Both, however, forget that the plant would cease to be a plant if it awoke, and that the brute would cease to be a brute the moment it began to speak. There is, no doubt, in language a transition from the material to the spiritual: the raw material of language belongs to nature, but the form of language, that which really makes language, belongs to the spirit. Were it possible to trace human language _directly_ back to natural sounds, to interjections or imitations, the question whether the Science of Language belongs to the sphere of the natural or the historical sciences would at once be solved. But I doubt whether this crude view of the origin of language counts one single supporter in Germany. With one foot language stands, no doubt, in the realm of nature, but with the other in the realm of the spirit. Some years ago, when I thought it necessary to bring out as clearly as possible the much neglected natural element in language, I tried to explain in what sense the Science of Language had a right to be called the last and the highest of the natural sciences. But I need hardly say that I did not lose sight, therefore, of the intellectual and historical character of language; and I may here express my conviction that the Science of Language will yet enable us to withstand the extreme theories of the evolutionists, and to draw a hard and fast line between spirit and matter, between man and brute. This short survey must suffice to show you how omnipresent the Science of Language has become in all spheres of human knowledge, and how far its limits have been extended, so that it often seems impossible for one man to embrace the whole of its vast domain. From this I wish, in conclusion, to draw some necessary advice.