{14 ADAPTATION AND PROGRESS 
coast: this is the dominant fact of American history. China forms a section 
of the Pacific rim. This is the fact back of the geographic distribution of 
Chinese emigration to Annam, Tonkin, Siam, Malacca, the Philippines, East 
Indies . . . Ecuador and Peru. 
As the earth is one, so is humanity. Its unity of species points to some 
degree of communication through a long prehistoric past. Universal history 
is not entitled to the name unless it embraces all parts of the earth and all 
peoples, whether savage or civilized. To fill the gaps in the written record it 
must turn to ethnography and geography, which by tracing the distribution 
and movements of primitive peoples can often reconstruct the most impor- 
tant features of their history. 
There are four fundamental classes of geographic influences 
according to our author: (1) direct and indirect physical, (2) 
direct and indirect psychical, (3) economic and social, and (4) 
effects upon movements of peoples. As illustrations of the direct 
effects working in conjunction with natural selection and espe- 
cially potent on primitive man, we have variations in stature, 
pigmentation and acclimatization; and of the indirect effects, 
such anatomical changes as result from certain occupations, 
these in turn being due to physical environment as in the case of 
the thin legs and thick arms of the Payaguas Indians due to so 
much of their life being spent in canoes.?. The psychical effects 
are registered in differences in temperament which differentiate 
peoples as well as in differences in literature and religion, while 
the indirect effects are seen in peculiarities of language reflecting 
local conditions and occupations. Under the third class we have 
the effect of physical environment on a group through the natural 
resources provided, the occupations encouraged or discouraged 
and the facilities for exchange offered; and under the fourth 
class, ‘‘ the effect of natural barriers . . . in obstructing or de- 
flecting the course of migrating people and in giving direction to 
national expansion, . . . the tendency of river valleys and tree- 
less plains to facilitate such movements, the power of rivers, lakes, 
bays and oceans either to block the path or open a highway, . . . 
and finally the influence of all these natural features in determin- 
1 Influence of Geographic Environment, p. 30. 
2 Tbid., pp. 34f. If due merely to occupation these characters would not be in- 
herited. 
3 Ibid., p. 41. 
