approximate.

There is something altogether out of the reach of science, and yet the
compass of science is practically illimitable. Hence it is that from
time to time we are startled and perplexed by theories which have no
parallel in the contracted moral world; for the generalizations of
science sweep on in ever-widening circles, and more aspiring flights,
through a limitless creation. While astronomy, with its telescope,
ranges beyond the known stars, and physiology, with its microscope, is
subdividing infinite minutiae, we may expect that our historic
centuries may be treated as inadequate counters in the history of the
planet on which we are placed. We must expect new conceptions of the
nature and relations of its denizens, as science acquires the materials
for fresh generalizations; nor have we occasion for alarms if a highly
advanced knowledge, like that of the eminent Naturalist before us,
confronts us with an hypothesis as vast as it is novel. This
hypothesis may or may not be sustainable hereafter; it may give way to
something else, and higher science may reverse what science has here
built up with so much skill and patience, but its sufficiency must be
tried by the tests of science alone, if we are to maintain our position
as the heirs of Bacon and the acquitters of Galileo. We must weigh
this hypothesis strictly in the controversy which is coming, by the only
tests which are appropriate, and by no others whatsoever.

The hypothesis to which we point, and of which the present work of Mr.
Darwin is but the preliminary outline, may be stated in his own
language as follows:--"Species originated by means of natural
selection, or through the preservation of the favoured races in the
struggle for life." To render this thesis intelligible, it is
necessary to interpret its terms. In the first place, what is a