Even more pernicious to the growth of sound ideas was the study of etymology, as formerly carried on in schools and universities. Everything here was left to chance or to authority, and it was not unusual that two or three etymologies of the same word had to be learnt, as if the same word might have had more than one parent. Yet it is many years since Otfried Müller told classical scholars that they must either surrender the whole subject of the historical growth of language, etymology, and grammatical morphology, or trust in these matters entirely to the guidance of Comparative Philology. As a student at Leipzig, I lived to see old Gottfried Hermann quoting the paradigms of Sanskrit grammar in one of his last _Programs_; and Boeckh declared in 1850, at the eleventh meeting of German philologists, that, in the present state of the science of language, the grammar of the classical languages cannot dispense with the coöperation of comparative grammar. And yet there are scholars even now who would exclude the Science of Language from schools and universities. What gigantic steps truly scientific etymology has made in Greek and Latin, every scholar may see in the excellent works of Curtius and Corssen. The essential difference between the old and the new systems consists here, too, in this, that while formerly people were satisfied if they knew, or imagined they knew, from what source a certain word was derived, little value is now attached to the mere etymology of a word, unless at the same time it is possible to account, according to fixed phonetic laws, for all the changes which a word has undergone in its passage through Latin, Greek, and Sanskrit. How far this conscientiousness may be carried is shown by the fact that the best comparative philologists decline to admit, on phonetic grounds, the identity of such words as the Latin _Deus_, and the Greek Θεός, although the strongest internal arguments may be urged in favor of the identity of these words.[1]