extending our knowledge of it. From the Latin side a great impetus was
given to the work by the foundation in 1884 of Wölfflin's _Archiv für
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.

One of its primary purposes, as its title indicates, was to investigate
the history of Latin words, and in its first number the editor called
attention to the importance of knowing the pieces of literature in which
each Latin word or locution occurred. The results have been very
illuminating. Some words or constructions or phrases are to be found, for
instance, only in comedy, satire, and the romance. They are evidently
peculiar to vulgar Latin. Others are freely used in these types of
literature, but sparingly employed in historical or rhetorical works. Here
again a shade of difference is noticeable between formal and familiar
usage. The method of the Latinist then is essentially one of comparison
and contrast. When, for instance, he finds the word _equus_ regularly used
by serious writers for "horse," but _caballus_ employed in that sense in
the colloquial compositions of Lucilius, Horace, and Petronius, he comes
to the conclusion that _caballus_ belongs to the vocabulary of every-day
life, that it is our "nag."

The line of reasoning which the Romance philologist follows in his study
of vulgar Latin is equally convincing. The existence of a large number of
words and idioms in French, Spanish, Italian, and the other Romance
languages can be explained only in one of three ways. All these different
languages may have hit on the same word or phrase to express an idea, or
these words and idioms may have been borrowed from one language by the
others, or they may come from a common origin. The first hypothesis is
unthinkable. The second is almost as impossible. Undoubtedly French, for