can modify our convictions.
This is especially the case when we inquire,--Are the various forms
under which man now exists primitive, or derived from pre-existing
forms; in other words, is man of one or many species? To this question
we immediately obtain distinct answers diametrically opposed to each
other: the one party positively maintaining, that man is a _species_ and
is essentially _one_--that all differences are but local and temporary
variations, produced by the different physical and moral conditions by
which he is surrounded; the other party maintaining with equal
confidence, that man is a genus of _many species_, each of which is
practically unchangeable, and has ever been as distinct, or even more
distinct, than we now behold them. This difference of opinion is
somewhat remarkable, when we consider that both parties are well
acquainted with the subject; both use the same vast accumulation of
facts; both reject those early traditions of mankind which profess to
give an account of his origin; and both declare that they are seeking
fearlessly after truth alone; yet each will persist in looking only at
the portion of truth on his own side of the question, and at the error
which is mingled with his opponent's doctrine. It is my wish to show how
the two opposing views can be combined, so as to eliminate the error and
retain the truth in each, and it is by means of Mr. Darwin's celebrated
theory of "Natural Selection" that I hope to do this, and thus to
harmonise the conflicting theories of modern anthropologists.

Let us first see what each party has to say for itself. In favour of the
unity of mankind it is argued, that there are no races without
transitions to others; that every race exhibits within itself variations
of colour, of hair, of feature, and of form, to such a degree as to
bridge over, to a large extent, the gap that separates it from other
races. It is asserted that no race is homogeneous; that there is a
tendency to vary; that climate, food, and habits produce, and render
permanent, physical peculiarities, which, though slight in the limited
periods allowed to our observation, would, in the long ages during which
the human race has existed, have sufficed to produce all the differences
that now appear. It is further asserted that the advocates of the
opposite theory do not agree among themselves; that some would make
three, some five, some fifty or a hundred and fifty species of man; some
would have