in warrens in Russia, remarks that their colour is a great
disadvantage, as they are thus more exposed to attack, and can be seen
during bright nights from a distance. A gentleman in Kent, who failed to
stock his woods with a nearly white and hardy kind of rabbit, accounted in
the same manner for their early disappearance. Any one who will watch a
white cat prowling after her prey will soon perceive under what a
disadvantage she lies.

The white Tartarian cherry, "owing either to its colour being so much like
that of the leaves, or to the fruit always appearing from a distance
unripe," is not so readily attacked by birds as other sorts. The
yellow-fruited raspberry, which generally comes nearly true by seed, "is
very little molested by birds, who evidently are not fond of it; so that
nets may be dispensed with in places where nothing else will protect the
red fruit."[557] This immunity, though a benefit to the gardener, would be
a disadvantage in a state of nature both to the cherry and raspberry, as
their dissemination depends on birds. I noticed during several winters that
some trees of the yellow-berried holly, which were raised from seed from a
wild tree found by my father, remained covered with fruit, whilst not a
scarlet berry could be seen on the adjoining trees of the common kind. A
friend informs me that a mountain-ash (_Pyrus aucuparia_) growing in his
garden bears berries which, though not differently coloured, are always
devoured by birds before those on the other trees. This variety of the
mountain-ash would thus be more freely disseminated, and the yellow-berried
variety of the holly less freely, than the common varieties of these two
trees.

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Independently of colour, other trifling differences are sometimes found to
be of importance to plants under cultivation, and would be of paramount
importance if they had to fight their own battle and to struggle with many
competitors. The thin-shelled peas, called _pois sans parchemin_, are
attacked by birds[558] much more than common peas. On the other hand, the
purple-podded pea, which has a hard shell, escaped the attacks of tomtits
(_Parus major_) in my garden far better than any other kind. The
thin-shelled walnut likewise suffers greatly from the tomtit.[559] These
same birds have been observed to pass over and thus favour the filbert,
destroying only the other kinds of nuts which grew in the same
orchard.[560]

Certain varieties of the pear have sof