k me that under these
circumstances favourable variations would tend to be preserved, and
unfavourable ones to be destroyed. The result of this would be the
formation of new species."[25]

Although Malthus gives no adumbration of the idea of Natural Selection
in his exposition of the eliminative processes which go on in mankind,
the suggestive value of his essay is undeniable, as is strikingly
borne out by the fact that it gave to Alfred Russel Wallace also "the
long-sought clue to the effective agent in the evolution of organic
species."[26] One day in Ternate when he was resting between fits of
fever, something brought to his recollection the work of Malthus which
he had read twelve years before. "I thought of his clear exposition of
'the positive checks to increase'--disease, accidents, war, and
famine--which keep down the population of savage races to so much
lower an average than that of more civilized peoples. It then occurred
to me that these causes or their equivalents are continually acting in
the case of animals also; and as animals usually breed much more
rapidly than does mankind, the destruction every year from these
causes must be enormous in order to keep down the numbers of each
species, since they evidently do not increase regularly from year to
year, as otherwise the world would long ago have been densely crowded
with those that breed most quickly. Vaguely thinking over the enormous
and constant destruction which this implied, it occurred to me to ask
the question, Why do some die and some live? And the answer was
clearly, that on the whole the best fitted live. From the effects of
disease the most healthy escaped; from enemies the strongest, the
swiftest, or the most cunning; from famine the best hunters or those
with the best digestion; and so on. Then it suddenly flashed upon me
that this self-acting process would necessarily _improve the race_,
because in every generation the inferior would inevitably be killed
off and the superior would remain--that is, _the fittest would
survive_."[27] We need not apologise for this long quotation, it is a
tribute to Darwin's magnanimous colleague, the Nestor of the
evolutionist camp,--and it probably indicates the line of thought
which Darwin himself followed. It is interesting also to recall the
fact that in 1852, when Herbert Spencer wrote his famous _Leader_
article on "The Development Hypothesis" in which he argued powerfully
for the thesis that the whole a