Page "Jacob Grimm" Paragraph 12

The purely scientific side of Grimm's character developed slowly.

He seems to have felt the want of definite principles of etymology without being able to discover them, and indeed even in the first edition of his grammar ( 1819 ) he seemed to be often groping in the dark.

As early as 1815 we find August Wilhelm von Schlegel reviewing the Altdeutsche Wälder ( a periodical published by the two brothers ) very severely, condemning the lawless etymological combinations it contained, and insisting on the necessity of strict philological method and a fundamental investigation of the laws of language, especially in the correspondence of sounds.

This criticism is said to have had a considerable influence on the direction of Grimm's studies.