JUNE 21, 1901.) 
COROLLARIES AND CONCLUSIONS. 
It will readily be understood that the 
center of gravity of evolutionary theories 
will appear to change on admitting the 
correctness of a kinetic view, and this_ 
not only in strictly biological, but in other 
related lines of thought. Time and space 
are alike wanting for the canvass of such 
readjustments ; it is possible in the way of 
summary and conclusion only to notice in 
a brief and disconnected manner a few of 
the corollaries and subsidiary theories ac- 
commodated or suggested by the belief that 
evolution is a general property of proto- 
plasm, and not the function of a special 
mechanism or a reaction to external stimuli. 
The differentiation of species is a phe- 
nomenon distinct from evolutionary prog- 
ress ; isolation may conduce to the former 
while retarding the latter. 
Selection, acting through isolation, affects 
evolution by influencing the direction and 
rate of progress with respect to particular 
characters; that species may originate 
through natural selection does not, how- 
ever, prove that selection is a cause of 
organic change or of evolution. 
Variation furnishes the differentials of 
which evolution is the integration; se- 
lection and isolation may affect the equa- 
tion either as positive or as negative quan- 
tities. Specific differentiation is a direct 
function of selection and isolation, but 
evolutionary progress is often an inverse 
function. 
Groups having large, complex and vari- 
able species, or numerous closely related 
species, are in a state of active evolution, 
while those in which species and genera 
are few, small and uniform have passed the 
zenith of their evolutionary history. Thus 
the compositae and hymenoptera are pros- 
perous, while the cycads and diplopods are 
on the decline. Primitive characters are to 
be sought in insular or circumscribed species 
rather than among related continental or 
SCIENCE. 
977 
widely distributed types. Static theories. 
would compel contrary inferences. 
In large and widely extended species uni- 
formity or diversity of characters depends 
upon relative facility of distribution; the 
more rapidly new characters can be dissem- 
inated the greater the uniformity of the 
species. Such uniformity should not, how- 
ever, be interpreted as stability, which may 
be relatively greater in locally diversified 
species. 
That diversity is not conditioned upon 
segregation, but is distinctly favored inside 
the limits of species, also seems obvious from 
the differentiations of sex, caste, dimorphism 
and other similar specializations. More- 
over, these phenomena do not represent a 
single device or adaptation, but have ap- 
peared independently in ‘many natural 
groups. 
The relative importance of natural selec- 
tion has differed greatly in the evolution of 
the various natural groups; in a general 
way it may be thought of as proportional to 
ecological diversity. 
Evolution is not a special process or func- 
tion, but appears in all types of individuals 
from the unicellular through the various 
grades of polycellular and compound organ- 
isms to the caste-differentiated colonies of 
the social insects ; it accompanies both sex- 
ual and asexual methods of reproduction, 
seedless plants and insects derived from un- 
fertilized eggs continuing to vary and differ- 
entiate. 
Evolution is both cellular or cytologic 
and supercellular or organic; the former 
appears in simple types and in the compo- 
nent cells of higher groups; the latter is a 
social phenomenon having no obvious or 
necessary connection with cytological proc- 
esses. 
In some groups it has been ascertained 
that evolutionary characters or conditions 
which first appeared in the adult are sub- 
sequently passed back into preliminary or 
