gradations of intellectual powers. Now, it seems to me, looking to
existing animals alone, that we have a very fine gradation in the
intellectual powers of the Vertebrata, with one rather wide gap (not half
so wide as in many cases of corporeal structure), between say a Hottentot
and a Ourang, even if civilised as much mentally as the dog has been from
the wolf. I suppose that you do not doubt that the intellectual powers are
as important for the welfare of each being as corporeal structure; if so, I
can see no difficulty in the most intellectual individuals of a species
being continually selected; and the intellect of the new species thus
improved, aided probably by effects of inherited mental exercise. I look
at this process as now going on with the races of man; the less
intellectual races being exterminated. But there is not space to discuss
this point. If I understand you, the turning-point in our difference must
be, that you think it impossible that the intellectual powers of a species
should be much improved by the continued natural selection of the most
intellectual individuals. To show how minds graduate, just reflect how
impossible every one has yet found it, to define the difference in mind of
man and the lower animals; the latter seem to have the very same attributes
in a much lower stage of perfection than the lowest savage. I would give
absolutely nothing for the theory of Natural Selection, if it requires
miraculous additions at any one stage of descent. I think Embryology,
Homology, Classification, etc., etc., show us that all vertebrata have
descended from one parent; how that parent appeared we know not. If you
admit in ever so little a degree, the explanation which I have given of
Embryology, Homology and Classification, you will find it difficult to say:
thus far the explanation holds good, but no further; here we must call in
"the addition of new creative forces." I think you will be driven to
reject all or admit all: I fear by your letter it will be the former
alternative; and in that case I shall feel sure it is my fault, and not the
theory's fault, and this will certainly comfort me. With regard to the