all must be ranked equally as species. So again, species within the
same large genus by no means resemble each other to the same degree: on
the contrary, some of them can generally be arranged in little groups
round other species, like satellites round planets. (20. Origin of
Species, 5th edit. p. 68.)
The question whether mankind consists of one or several species has of
late years been much discussed by anthropologists, who are divided into
the two schools of monogenists and polygenists. Those who do not admit
the principle of evolution, must look at species as separate creations,
or in some manner as distinct entities; and they must decide what forms
of man they will consider as species by the analogy of the method
commonly pursued in ranking other organic beings as species. But it is
a hopeless endeavour to decide this point, until some definition of the
term species is generally accepted; and the definition must not
include an indeterminate element such as an act of creation. We might
as well attempt without any definition to decide whether a certain
number of houses should be called a village, town, or city. We have a
practical illustration of the difficulty in the never-ending doubts
whether many closely-allied mammals, birds, insects, and plants, which
represent each other respectively in North America and Europe, should
be ranked as species or geographical races; and the like holds true of
the productions of many islands situated at some little distance from
the nearest continent.
Those naturalists, on the other hand, who admit the principle of
evolution, and this is now admitted by the majority of rising men, will
feel no doubt that all the races of man are descended from a single
primitive stock; whether or not they may think fit to designate the
races as distinct species, for the sake of expressing their amount of
difference. (21. See Prof. Huxley to this effect in the Fortnightly
Review, 1865, p. 275.) With our domestic animals the question whether
the various races have arisen from one or more species is somewhat
different. Although it may be admitted that all the races, as well as
all the natural species within the same genus, have sprung from the
same primitive stock, yet it is a fit subject for discussion, whether
all the domestic races of the dog, for instance, have acquired their
present amount of difference since some one species was first
domesticated by man; or whether they owe some of their characters to
inheritance from distinct species, which had already been
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