.]

[Footnote 47: _Essays on Evolution_, 1889-1907, Oxford, 1908,
_passim_, e.g. p. 269.]

[Footnote 48: The expression does not refer to all the enemies of this
butterfly; against ichneumon-flies, for instance, their unpleasant
smell usually gives no protection.]

[Footnote 49: Professor Poulton has corrected some wrong descriptions
which I had unfortunately overlooked in the Plates of my book
_Vortraege ueber Descendenztheorie_, and which refer to _Papilio
dardanus_ (_merope_). These mistakes are of no importance as far as an
understanding of the mimicry-theory is concerned, but I hope shortly
to be able to correct them in a later edition.]

[Footnote 50: _Journ. Linn. Soc. London_ (_Zool._), Vol. xxvi. 1898,
pp. 598-602.]

[Footnote 51: In _Kosmos_, 1879, p. 100.]

[Footnote 52: _Habit and Instinct_, London. 1896.]

[Footnote 53: This has been discussed in many of my earlier works. See
for instance _The All-Sufficiency of Natural Selection, a reply to
Herbert Spencer_, London, 1893.]

[Footnote 54: _The Evolution Theory_, London, 1904, p. 144.]

[Footnote 55: _Variation under Domestication_, 1875, II. pp. 426,
427.]

III

HEREDITY AND VARIATION IN MODERN LIGHTS

BY W. BATESON, M.A., F.R.S.

_Professor of Biology in the University of Cambridge_

Darwin's work has the property of greatness in that it may be admired
from more aspects than one. For some the perception of the principle
of Natural Selection stands out as his most wonderful achievement to
which all the rest is subordinate. Others, among whom I would range
myself, look up to him rather as the first who plainly distinguished,
collected, and comprehensively studied that new class of evidence from
which hereafter a true understanding of the process of Evolution may
be developed. We each prefer our own standpoint of admiration; but I
think that it will be in their wider aspect that his labours will most
command the veneration of posterity.

A treatise written to advance knowledge may be read in two moods. The
reader may keep his mind passive, willing merely to receive the
impress of the writer's thought; or he may read with his attention
strained and alert, asking at every instant how the new knowledge can
be used in a further advance, watching continually for fresh footholds
by which to climb higher still. Of Shelley it has been said that he
was a poet for poets: so Darwin was a naturalist for naturalists. It
is when his writings ar