18;
that immunity from attack with which it is generally
credited. “ The arctic fox, the ermine, and the alpine
hare,” says Mr. Wallace, “ change to white in winter only,
because in summer white would be more conspicuous than
any other colour, and therefore a danger rather than a
protection.”* This is the assumption necessary in order
to establish the proposition that winter white has been
brought about by Natural Selection. But in order that
winter white should be a protection to animals, it is essen
tial that snow should remain upon the ground during the
winter months, and that winter white should only be
assumed by animals during the season when the landscape
is covered with snow. But neither of these conditions are
present in the actual world of nature. The winter white of
animals is not confined to countries in which the snow is on
the ground constantly during a given period. There is no
such definite period in some countries, and yet the animal
is white through the winter months. “The stoat always
becomes white in the alpine districts of Scotland, frequently
in the North of England, occasionally in the Midlands,
and Mr. Couch has seen two white stoats in Cornwall.”f
It may be said that this is a characteristic which has
become fixed in the race. That might account for the
present condition of the species. But if the species arose
through the elimination of the conspicuous colours, and if
that is a constant law of nature, then it ought to have been
exterminated by the same principle, if it persists in main
taining a conspicuous white in a country which is only
occasionally covered with snow. In New Brunswick the
winter lasts from the middle of December till the middle
of March,I but in New Brunswick the American hare
* Contributions, p. jo.
t Poulton. pp. 101-2.
i Chambers' Encyclopaedia.