SEGREGATE FECUNDITY, VIGOR, AND ADAPTATION. Le 7 fa 
offspring produced by crossing with other species or varieties. Nat- 
ural selection is the survival of the best adapted of the variations that 
remain and breed with the stock under consideration, but it takes no 
eognizance of the fitness or lack of fitness of individuals or a race that 
separate themselves from the intergenerating mass. The different 
grades of fitness for their new life found among the individuals that 
form the new intergenerating group will be the ground for divergent 
natural selection in the new group; but they will not affect the type 
of the original stock. Now, whenever the conditions and aptitudes of 
the two groups are so different that the offspring of cross-unions are 
less fitted for life under either set of conditions than is either group of 
the pure-breeds for its own peculiar life, we shall have a new principle, 
different in its effects from natural selection. This I call segregate 
adaptation. Natural selection is the survival of the fittest that inter- 
generate; segregate adaptation is the superior fitness and survival of 
the offspring produced by segregate generation. 
20, 21. Segregate Freedom from Competition and Segregate Escape from Enemies. 
Segregative endowments may be necessary to the enjoyment of cer- 
tain advantages which are gained not by superior adaptation to the 
environment, but by endowments that set them in a position where 
competitors and enemies are as yet few. These two principles I have 
called segregate freedom from competition and segregate escape from 
enemies. Segregate freedom from competition or segregate access to 
unused resources results when the pure offspring have freer access to 
unused resources than do the cross-breeds or the original stock. 
Segregate escape from enemies (an advantage often of equal import- 
ance with that just mentioned) arises whenever the pure offspring 
of a divergent variety are able to occupy a position freer from enemies 
than that occupied by the original stock. 
(c) INSTITUTIONAL SEGREGATION. 
Institutional segregation is the reflexive form of rational segrega- 
tion. It is produced by the rational purposes of man embodied in 
institutions that prevent free intergeneration between the different 
parts of the same race. 
As the principal object of the present paper is to call attention to 
the causes of segregation acting independently of effort and contriv- 
ance directed by man to that end, it will be sufficient to enumerate 
some of the more prominent forms under which institutional segrega- 
tion presents itself, noting that some of these influences come in as 
