In elucidating these points, we may fitly begin by considering the
question as to the possibility of the evolution of any higher creature
than Man, to whom the dominion over this earth shall pass. The question
will best be answered by turning back and observing one of the most
remarkable features connected with the origin of Man and with his
superiority over other animals. And let it be borne in mind that we are
not now about to wander through the regions of unconditional
possibility. We are not dealing with vague general notions of
development, but with the scientific Darwinian theory, which alleges
development only as the result of certain rigorously defined agencies.
The chief among these agencies is Natural Selection. It has again and
again been illustrated how by the cumulative selection and inheritance
of slight physical variations generic differences, like those between
the tiger and the leopard, or the cow and the antelope, at length arise;
and the guiding principle in the accumulation of slight physical
differences has been the welfare of the species. The variant forms on
either side have survived while the constant forms have perished, so
that the lines of demarcation between allied species have grown more and
more distinct, and it is usually only by going back to fossil ages that
we can supply the missing links of continuity. In the desperate struggle
for existence no peculiarity, physical or psychical, however slight, has
been too insignificant for natural selection to seize and enhance; and
the myriad fantastic forms and hues of animal and vegetal life
illustrate the seeming capriciousness of its workings. Psychical
variations have never been unimportant since the appearance of the first
faint pigment-spot which by and by was to translate touch into vision,
as it developed into the lenses and humours of the eye.[2] Special
organs of sense and the lower grades of perception and judgment were
slowly developed through countless ages, in company with purely physical