Chapter XXI: The Relative Importance of Tradition and Heredity 437

(1) Definite conclusions are difficult to reach. (2) History in
the intermediate period was due to germinal change. (3) The
natural endowment of America, (4) Asia, (5) Africa, (6) and of
other regions, (7) and their geographical features, (8) suggests
that history in the subsequent periods was chiefly of the nature
of traditional change. (9) Though germinal changes are important
they do not account for the outstanding events, though they have
contributed to them. (10) Lesser germinal changes colour
tradition, but are not determining factors in history. (11)
Known germinal changes, such as those produced by crossing, are
less important than accompanying traditional changes, (12) of
which there are many instances in the third period. (13) The
direct effect of the environment is not negligible, and has
influenced the course of history. (14) The cyclic course of
civilization, which has been attributed to germinal change, is
in the main due to traditional changes. (15) Tradition at the
present day overlays the manifestation of mental characters in
so great a degree that (16) differences between classes may well
seem wholly traditional, but (17) psychological tests and (18)
other evidence show that innate mental differences are present,
(19) though it is difficult to appraise their value and the
importance of modern differential fertility.