e of novelty in its present
application. Therefore a summary review of its logical grounds may
not be uncalled for, even at the risk of some tedious repetition and
formulation of commonplaces.

Social evolution is a process of selective adaptation of temperament and
habits of thought under the stress of the circumstances of associated
life. The adaptation of habits of thought is the growth of institutions.
But along with the growth of institutions has gone a change of a more
substantial character. Not only have the habits of men changed with the
changing exigencies of the situation, but these changing exigencies
have also brought about a correlative change in human nature. The human
material of society itself varies with the changing conditions of life.
This variation of human nature is held by the later ethnologists to be
a process of selection between several relatively stable and persistent
ethnic types or ethnic elements. Men tend to revert or to breed true,
more or less closely, to one or another of certain types of human nature
that have in their main features been fixed in approximate conformity
to a situation in the past which differed from the situation of today.
There are several of these relatively stable ethnic types of mankind
comprised in the populations of the Western culture. These ethnic types
survive in the race inheritance today, not as rigid and invariable
moulds, each of a single precise and specific pattern, but in the form
of a greater or smaller number of variants. Some variation of the ethnic
types has resulted under the protracted selective process to which
the several types and their hybrids have been subjected during the
prehistoric and historic growth of culture.

This necessary variation of the types themselves, due to a selective
process of considerable duration and of a consistent trend, has not been
sufficiently noticed by the writers who have discussed ethnic survival.
The argument is here concerned with two main divergent variants of human
nature resulting from this, relatively late, selective adaptation of
the ethnic types comprised in the Western culture; the point of interest
being the probable effect of the situation of today in furthering
variation along one or the other of these two divergent lines.

The ethnological position may be briefly summed up; and in order to
avoid any but the most indispensable detail the schedule of types and
variants and the scheme of reversion and s