the time of the famous Bakewell, during the last
century, the Leicester sheep have been bred with the most scrupulous care;
yet occasionally grey-faced, or black-spotted, or wholly black lambs
appear.[69] This occurs still more frequently with the less improved
breeds, such as the Norfolks.[70] As bearing on this tendency in sheep to
revert to dark colours, I may state (though in doing so I trench on the
reversion of crossed breeds, and likewise on the subject of prepotency)
that the Rev. W. D. Fox was informed that seven white Southdown ewes were
put to a so-called Spanish ram, which had two small black spots on his
sides, and they produced thirteen lambs, all perfectly black. Mr. Fox
believes that this ram belonged to a breed which he has himself kept, and
which is always spotted with black and white; and he finds that Leicester
sheep crossed by rams of this breed always produce black lambs: he has gone
on recrossing these crossed sheep with pure white Leicesters during three
successive {31} generations, but always with the same result. Mr. Fox was
also told by the friend from whom the spotted breed was procured, that he
likewise had gone on for six or seven generations crossing with white
sheep, but still black lambs were invariably produced.

Similar facts could be given with respect to tailless breeds of various
animals. For instance, Mr. Hewitt[71] states that chickens bred from some
Rumpless fowls, which were reckoned so good that they won a prize at an
exhibition, "in a considerable number of instances were furnished with
fully developed tail-feathers." On inquiry, the original breeder of these
fowls stated that, from the time when he had first kept them, they had
often produced fowls furnished with tails; but that these latter would
again reproduce rumpless chickens.

Analogous cases of reversion occur in the vegetable kingdom; thus "from
seeds gathered from the finest cultivated varieties of Heartsease (_Viola
tricolor_), plants perfectly wild both in their foliage and their flowers
are frequently produced;"[72] but the reversion in this instance is not to
a very ancient period, for the best existing varieties of the heartsease
are of comparatively modern origin. With most of our cultivated vegetables
there is some tendency to reversion to what is known to be, or may be
presumed to be, their aboriginal state; and this would be more evident if
gardeners did not generally look over their beds of seedlings, and p