nt, and ensures its being transmitted faithfully; when a
statement is communicated orally, the impression in the mind of the
hearer is apt to be modified by confusion with other impressions; in
passing from one intermediary to another the statement is modified at
every step,[158] and as these modifications arise from different causes,
there is no possibility of measuring or correcting them.

Oral tradition is by its nature a process of continual alteration; hence
in the established sciences only written transmission is accepted.
Historians have no avowable motive for proceeding differently, at any
rate when it is a case of establishing a particular fact. We must
therefore search documents for statements derived from oral tradition in
order that we may suspect them. We rarely have direct information as to
statements being thus derived; authors who borrow from oral tradition
are not anxious to proclaim the fact.[159] There is thus only an
indirect method, and that is to ascertain that written transmission was
impossible; we may then be sure that the fact reached the author only by
oral tradition. We have therefore to ask the question: In this period
and in this group of men was it customary to commit to writing facts of
this kind? If the answer is negative, the fact considered rests on oral
tradition alone.

The most striking form of oral tradition is _legend_. It arises among
groups of men with whom the spoken word is the only means of
transmission, in barbarous societies, or in classes of little culture,
such as peasants or soldiers. In this case it is the whole group of
facts which is transmitted orally and assumes the legendary form. There
is a legendary period in the early history of every people: in Greece,
at Rome, among the Germanic and Slavonic races, the most ancient
memories of the people form a stratum of legend. In periods of
civilisation popular legends continue to exist in reference to events
which strike the imagination of the people.[160] Legend is exclusively
oral tradition.

When a people has emerged from the legendary period and begun to commit
its history to writing, oral tradition does not come to an end, but only
applies to a narrower sphere; it is now restricted to facts which are
not registered, whether because they are by their nature secret, or
because no one takes the trouble to record them, such as private
actions, words, the details of events. Thus arise _anecdotes_, which
have been named