perhaps one of the least modified varieties of the cabbage; and in the third
generation some of the plants came very close to the forms now established in
England about old castle-walls, and called indigenous."

REVERSION IN ANIMALS AND PLANTS WHICH HAVE RUN WILD.

In the cases hitherto considered, the reverting animals and plants have not
been exposed to any great or abrupt change in their conditions of life which
could have induced this tendency; but it is very different with animals and
plants which have become feral or run wild. It has been repeatedly asserted in
the most positive manner by various authors, that feral animals and plants
invariably return to their primitive specific type. It is curious on what
little evidence this belief rests. Many of our domesticated animals could not
subsist in a wild state; thus, the more highly improved breeds of the pigeon
will not "field" or search for their own food. Sheep have never become feral,
and would be destroyed by almost every beast of prey. (13/10. Mr. Boner speaks
('Chamois-hunting' 2nd edition 1860 page 92) of sheep often running wild in
the Bavarian Alps; but, on making further inquiries at my request, he found
that they are not able to establish themselves; they generally perish from the
frozen snow clinging to their wool, and they have lost the skill necessary to
pass over steep icy slopes. On one occasion two ewes survived the winter, but
their lambs perished.) In several cases we do not know the aboriginal parent-
species, and cannot possibly tell whether or not there has been any close
degree of reversion. It is not known in any instance what variety was first
turned out; several varieties have probably in some cases run wild, and their
crossing alone would tend to obliterate their proper character. Our
domesticated animals and plants, when they run wild, must always be exposed to
new conditions of life, for, as Mr. Wallace (13/11. See some excellent remarks
on this subject by Mr. Wallace 'Journal Proc. Linn. Soc.' 1858 volume 3 page
60.) has well remarked, they have to obtain their own food, and are exposed to