144 CLASSIFICATION OF THE FORMS OF THE PRINCIPLES. 
cess in all climates and inall countries. Moreover, under the stimulus 
of intercourse with European civilization, there are evident signs that 
new and progressive elements will be added to the old ideals tilla truly 
progressive spirit is attained. The remarkable power of accommoda- 
tion to different climates and health conditions possessed by the race, 
especially by the branch occupying the southern provinces of China, 
is such that few races are able to endure free competition with them 
even when the country and climate are so chosen as to give the best pos- 
sible chance to their rivals. Members of the Teutonic race, when sub- 
jected to the climate of India, suffer from the effects of the heat; and 
their small power of individual adaptive modification in that direction 
gives them but little prospect of becoming completely adapted through 
the effects of natural selection; for, if their children remain contin- 
uously in the country, they have not sufficient energy for the battle of 
life. On the other hand, the Chinese from Canton, with high powers 
of accommodation, are fully successful as permanent settlers, both in 
the cold of Manchuria and in the heat of the Malay Peninsula, Borneo, 
and the Philippine Islands, and if completer racial adjustment is 
needed, they are sure to attain to it in the course of generations, through 
the accumulation of coincident variations. 
In the last chapter of his Problems of Evolution, Headley discussed 
from a biological point of view some of the problems arising in the 
intercourse of eastern and western races. 
III. AN UNWARRANTED ASSUMPTION. 
In discussing the influences producing evolution some writers have 
assumed that all diversity of survival in different groups of individ- 
uals of the same species is due to diversity in the environments to 
which the groups are exposed; and as natural selection is defined 
as the influence of the environment in determining what individuals 
shall survive, the inference is reached that diversity of natural 
selection is the only influence producing diversity of survival. A 
careful study, however, of causes producing diversity of survival in 
isolated groups shows that this assumption is without foundation. 
In the first place, it ignores the fact that diversity in sexual selection, 
and in any one of the other forms of reflexive selection, depends on 
diversity in the influence of members of the group upon each other, 
and that these influences may pass through a considerable range of 
divergence without change in the conditions lying outside of the 
species. In the case of man the forms of reflexive selection depend 
chiefly on the form of social organization, which may be subject to 
great change without reference to change in the environment of the 
