We have reason for believing that up to the time when this division took place in the country south of the Caspian Sea, the Aryan people spoke one language; but sufficient time had already elapsed for a considerable change to have taken place in the tongue which was spoken on the plains at the foot of the Hindoo Kosh. Language changes rapidly among people in a low state of civilization, without literature, without letters which are the landmarks and conservators of speech. But this point of time and of place is that of a great division in the speech of the Aryan people. Of the language of those who moved westward into Europe there are no remains which date within many centuries of this period; but of the language of those who moved south into Hindostan, we have in the existing Sanskrit a representative which is of almost indefinable antiquity, and the perfect preservation of which is marvelous. It is no rude, ruinous relic, but complete, elaborate, and finished to the highest point of perfection in its kind. It will be seen (and this must be constantly borne in mind) that Sanskrit is not the original Aryan language, but only the oldest existing offshoot from that language. The great, the inestimable value of the discovery of Sanskrit was not that we find in it the source of other languages, not that in it was the origin of the words spoken by the various peoples of Europe; but that it furnished evidence of the most important fact in the history of language, one of the most important facts in the history of the world. It had been assumed that the countless words which were similar in the language of the European peoples, and the many which were identical, were derived one from another; that they were adopted by one people from the language of another; that they were the product of neighborhood, of intercourse, of imitation, of convection—that is that they were carried from one country and people into another. The discovery and the study of Sanskrit proved that these words, or most of them, came into the various languages in which they are found, not by any or by all of these methods, but by direct descent from a speech which was at one time common to the forefathers of all the peoples in India, in Persia, and in Europe. Of these various languages Sanskrit is not only the oldest, but so very much the oldest that it carries us up very far toward the original speech of the Aryan or Indo-European race; so far that we are not without reasonable hope that philological science may elaborate by its help a proximate form of the elements of the original Aryan speech.