CRITIQUE OF DARWINISM 255 
Darwin came very near to this conception of definite variability when 
he pointed out that “if a country were changing, the altered conditions 
would tend to cause variation, not but what I believe most beings 
vary at all times enough for selection to act on.” Extermination 
would expose the remainder to the “mutual action of a different set of 
inhabitants, which I believe to be more important to the life of each 
being than mere climate,” and as “the same spot will support more 
life if occupied by very diverse forms,’ it is evident that selection 
will favour very great diversity of structure. 
Bearing in mind this cumulative action of selection it will follow 
that under constant or relatively constant conditions the struggle for 
successful living will become more and more selective in character, 
even if the actual number of inhabitants remain more or less the same 
as when the struggle first commenced. The selection of variations 
will thus tend to pass through certain more or less ill-defined, but 
nevertheless, real stages. In proportion as the struggle becomes 
intense, either from the number or from the increasing adaptability 
of the organisms, or both, certain major essential adaptations, which 
were necessary for the climatic and other more or less comparatively 
simple conditions, will be supplemented by minor auxiliary variations 
which in the earlier stages would not have appeared. And still later, 
as more and more rigorous conditions of life were imposed, the advan- 
tage would tend to rest with those organisms which possessed highly 
co-ordinated adaptations, since this would entail more rapid respon- 
siveness to environment. 
As evolution advances from the unspecialised to the specialised, 
and higher and higher forms of life come into being, with increasing 
complexity and specialisation of parts entailing an increasingly delicate 
adjustment of those parts to each other’s needs, the relation of each 
part to the whole organism becomes of more and more importance, 
and it follows that selection must become more and more generalised 
in its action. No single variation could be of service to any of the 
higher forms of life unless it was in more or less complete harmony 
with the whole tendency of the individual. The adjustment of parts 
and their mutual interdependence make it essential for adaptation 
that the relation of parts be preserved; consequently, correlated 
minute favourable variations will tend to be more and more selected 
as evolution passes from the unspecialised to the specialised forms of 
life. This response of the whole organism should be still more delicate 
in those forms of life that are continually subjecting themselves to 
