_4. As suggested by an examination of text-books_

When we turn from literature to the text-books used in schools and
colleges, we find the need of supplementing greatly increased. Writers
of literature are at liberty to choose any topic they please, and to
treat it as fully as they will. But writers of text-books are free in
neither of these respects. Their subjects are determined for them; it
is the history, for example, of a given period, the grammar of the
English language, the geography of the earth. And these must be
presented briefly enough to be covered by classes within a prescribed
time. For these reasons text-books contain far less detail than
literature, and in that sense are much more condensed. They are only
the outlines of subjects, as their titles often directly acknowledge.
Green's _History of England_, for instance, which has been extensively
used as a college text, barely touches many topics that are treated at
great length elsewhere. It is natural, therefore, that in our more
advanced schools the word text in connection with such books is used
in much the same sense as in connection with the Bible; a text is that
which merely introduces topics by giving the bare outline of facts, or
very condensed statements; it must be supplemented extensively, if the
facts or thoughts are to be appreciated.

How about the texts used in the elementary school? Those used in the
highest two grades need, perhaps, somewhat more supplementing than
those in the high school. But in the middle grades this need is still
greater. In the more prominent studies calling for text-books, such as
history, geography, and English language or grammar, nearly the same
topics are treated as in the higher grades, and in substantially the
same manner. But since the younger children are not expected to take