THE INTERACTION OF RACIAL AND SOCIAL EVOLUTION. 49 
and, as will be more fully explained in another chapter, it is brought 
about by the codperation of habitudinal demarcation through parti- 
tion, and habitudinal intensification through election. The methods of 
this election are first through the different forms of approval and disap- 
proval used in training the young, and second through the promotion 
and wide influence given to individuals attaining the highest recog- 
nition of public opinion and the suppression of individuals falling 
below the lower limits set by the laws and customs of the community. 
Divergent forms of civilization can neither be established nor main- 
tained without the continuous operation of segregate association. 
For designating the effects of segregate association I often use the 
term “‘habitudinal segregation”’ rather than ‘‘social segregation,”’ 
because in creatures entirely guided by instinct there may be elab- 
orate forms of social organization, and therefore forms of social segre- 
gation, that rest mainly, if not entirelv, on racial characters produced 
by racial segregation; while under “ habitudinal segregation’’ I wish 
to consider the evolution of acquired characters under the operation of 
segregate association. If ants and bees learn by training and imita- 
tion incorporated in traditions, then the growth of their social organ- 
izations should be treated under this department of segregation; but, 
if not, then their evolution, both physical and social, comes under the 
department of racial segregation. 
4. The Interaction of Racial and Social Evolution must be considered. 
The interaction of racial and social (or habitudinal) evolution and 
the exposition of the laws regulating the same, by which man is to 
gain control of his own evolution, is the broad sphere in which the 
biology and sociology of the future will expand. Ward, Giddings, 
Baldwin, and other Americans are exploring this field, and in Europe 
the trend is in the same direction, if I judge rightly. The nomen- 
clature which I propose and illustrate in the following pages will, I 
think, aid in discussing the problems of biology and sociology that are 
now coming to the front. I should not have had the patience and 
courage to attempt to present a scheme for so wide a field if I had not 
seen the pressing need for such a method from the side of biology. I 
also believe it will be a great advantage for sociology if a harmonious 
and correlated nomenclature can be brought into use in both biology 
and sociology. Some sociologists, recalling the nomenclature and 
exposition introduced by Herbert Spencer on the basis of an assumed 
correspondence between the biological and the social organism, will 
instinctively shun the use of a terminology that suggests a correspon- 
dence and interdependence between the two spheres of evolution. 
There will, however, be others, who have come into sufficiently close 
