Nor was it long before a reaction set in. One scholar from the very first, and almost contemporaneously with Bopp’s first essays on Comparative Grammar, devoted himself to the study of one branch of languages only, availing himself, as far as he was able, of the new light which a knowledge of Sanskrit had thrown on the secret history of the whole Aryan family of speech, but concentrating his energies on the Teutonic; I mean, of course, Jacob Grimm, the author of the great historical grammar of the German language; a work which will live and last long after other works of that early period shall have been forgotten, or replaced, at least, by better books. After a time Grimm’s example was followed by others. Zeuss, in his “Grammatica Celtica,” established the study of the Celtic languages on the broad foundations of Comparative Grammar. Miklosich and Schleicher achieved similar results by adopting the same method for the study of the Slavonic dialects. Curtius, by devoting himself to an elucidation of Greek, opened the eyes of classical scholars to the immense advantages of this new treatment of grammar and etymology; while Corssen, in his more recent works on Latin, has struck a mine which may well tempt the curiosity of every student of the ancient dialects of Italy. At the present moment the reaction is complete; and there is certainly some danger, lest what was called a _syncretistic_ spirit should now be replaced by an _isolating_ spirit in the science of language. It cannot be denied, however, that this isolating, or rather discriminating, tendency has produced already the most valuable results, and I believe that it is chiefly due to the works of Curtius and Corssen, if Greek and Latin scholars have been roused at last from their apathy and been made aware of the absolute necessity of Comparative Philology, as a subject to be taught, not only in every university but in every school. I believe it is due to their works that a conviction has gradually been gaining ground among the best scholars at Oxford, also, that Comparative Philology could no longer be ignored as an important ingredient in the teaching of Greek and Latin; and while a comparative analysis of Sanskrit, Zend, Armenian, Greek, Latin, Gothic, High-German, Lithuanian, Slavonic, and Celtic, such as we find it in Bopp’s “Comparative Grammar,” would hardly be considered as a subject of practical utility, even in a school of philology, it was recognized at last that, not only for sound principles of etymology, not only for a rational treatment of Greek and Latin grammar, not only for a right understanding of classical mythology, but even for a critical restoration of the very texts of Homer and Plautus, a knowledge of Comparative Philology, as applied to Greek and Latin, had become indispensable.