equirement must, of course, be modified considerably
in practice. The date at which a modern language is to be regarded by
the lexicographer as "beginning" must, as a rule, be somewhat
arbitrarily chosen; while considerable portions of its earlier
vocabulary cannot be recovered because of the incompleteness of the
literary record. Moreover, not even the most complete dictionary can
include all the words which the records--earlier and later--actually
contain. Many words, that is to say, which are found in the literature
of a language cannot be regarded as, for lexicographic purposes,
belonging to that language; while many more may or may not be held to
belong to it, according to the judgment--almost the whim--of the
individual lexicographer. This is especially true of the English tongue.
"That vast aggregate of words and phrases which constitutes the
vocabulary of English-speaking men presents, to the mind that endeavours
to grasp it as a definite whole, the aspect of one of those nebulous
masses familiar to the astronomer, in which a clear and unmistakable
nucleus shades off on all sides, through zones of decreasing brightness,
to a dim marginal film that seems to end nowhere, but to lose itself
imperceptibly in the surrounding darkness" (Dr J. A. H. Murray, _Oxford
Dict._ General Explanations, p. xvii). This "marginal film" of words
with more or less doubtful claims to recognition includes thousands of
the terms of the natural sciences (the New-Latin classificatory names of
zoology and botany, names of chemical compounds and of minerals, and the
like); half-naturalized foreign words; dialectal words; slang terms;
trade names (many of which have passed or are passing into common use);
proper names and many more. Many of these even the most complete
dictionary should exclude; others it should include; but where the line
shall be drawn will always remain a vexed question.

Another important principle upon which Trench insisted, and which also
expresses a requirement of modern scientific philology, is that the
dictionary shall be not merely a record, but also an _historical_ record
of words and their uses. From the literary point of view the most
important thing is present usage. To that alone the idea of a "standard"
has any application. Dictionaries of the older type, therefore, usually
make the common, or "proper" or "root" meaning of a word the starting
point of its definition, and arrange its other senses in a logical