It was left for the nineteenth century, however, to furnish scientific proof of the correctness of this hypothesis, and it was a fitting thing that the existence of an unbroken line of connection between popular Latin of the third century before our era, and the Romance languages of the nineteenth century, should have been established at the same time by a Latinist engaged in the study of Plautus, and a Romance philologist working upward toward Latin. The Latin scholar was Ritschl, who showed that the deviations from the formal standard which one finds in Plautus are not anomalies or mistakes, but specimens of colloquial Latin which can be traced down into the later period. The Romance philologist was Diez, who found that certain forms and words, especially those from the vocabulary of every-day life, which are common to many of the Romance languages, are not to be found in serious Latin literature at all, but occur only in those compositions, like comedy, satire, or the realistic romance, which reflect the speech of the every-day man. This discovery made it clear that the Romance languages are related to folk Latin, not to literary Latin. It is sixty years since the study of vulgar Latin was put on a scientific basis by the investigations of these two men, and during that period the Latinist and the Romance philologist have joined hands in extending our knowledge of it. From the Latin side a great impetus was given to the work by the foundation in 1884 of Woelfflin’s Archiv fuer lateinische Lexikographie und Grammatik. This periodical, as is well known, was intended to prepare the way for the publication of the Latin Thesaurus, which the five German Academies are now bringing out.