282 DIVERGENT EVOLUTION THROUGH SEGREGATION. 
DIVERGENT EVOLUTION NOT EXPLAINED BY “THE ADVANTAGE OF 
DIVERGENCE OF CHARACTER.” 
Two sections of the fourth chapter of the “Origin of species” are 
given to the discussion of the “ principle of benefit being derived from 
divergence of character,” which it is maintained ‘‘ will generally lead 
to the most different or divergent variations being preserved and accu- 
mulated by natural selection.” Now, it can not be doubted that ability 
to appropriate unused resources would be an advantage to any members 
of a community pressed for food; but I do not see how the divergence 
that would enable them to appropriate, for example, a new kind of food 
can be accumulated while free crossing continues; and natural selection 
can not prevent the free crossing of competitors who leave progeny. 
Having found that the evolution of the fitted is secured through the 
prevention of crossing between the better fitted and the less fitted, can 
we believe that the evolution of a special race, regularly transmitting 
a special kind of fitness, can be realized without any prevention of cross- 
ing with other races that have no power to transmit that special kind of 
fitness? Can we suppose that any advantage, derived from new pow- 
ers that prevent severe competition with kindred, can he permanently 
transmitted through sueceeding generations to one small section of the 
species while there is free crossing equally distributed between all the 
families of the species? Is it not apparent that the terms of this sup- 
position are inconsistent with the fundamental laws of heredity? Does 
not inheritance follow the lines of consanguinity, and when consan- 
guinity is widely diffused, can inheritance be closely limited? When 
there is free crossing between the families of one species, will not any 
peculiarity that appears in one family either be neutralized by crosses 
with families possessing the opposite quality, or being preserved by 
natural selection, while the opposite quality is gradually excluded, will 
not the new quality gradually extend to all the branches of the species, 
so that, in this way or in that, increasing divergence of form will be 
prevented? 
If the advantage of freedom from competition in any given variation 
depends on the possession, in some degree, of new adaptations to unap- 
propriated resources, there must be some cause that favors the breed- 
ing together of those thus specially endowed, and interferes in some 
degree with their crossing with other variations, or, failing of this, the 
special advantage will in succeeding generations be lost. As some 
degree of independent generation is necessary for the continuance of 
the advantage, it is evident that the same condition is necessary for 
the accumulation through natural selection of the powers on which the 
advantage depends. The advantage of divergence of character can not 
be retained by those that fail to retain the divergent character ; and diver- 
gent character can not be retained by those that are constantly crossing 
with other kinds ; and the prevention of free crossing between those that 
are equally successful is in no way secured by natural selection. 
