un in the stock, is gaining new advocates every day."[20] So it {11}
is in regard to cattle, with consumption, good and bad teeth, fine skin,
&c. &c. But enough, and more than enough, has been said on disease. Andrew
Knight, from his own experience, asserts that disease is hereditary with
plants; and this assertion is endorsed by Lindley.[21]

Seeing how hereditary evil qualities are, it is fortunate that good health,
vigour, and longevity are equally inherited. It was formerly a well-known
practice, when annuities were purchased to be received during the lifetime
of a nominee, to search out a person belonging to a family of which many
members had lived to extreme old age. As to the inheritance of vigour and
endurance, the English race-horse offers an excellent instance. Eclipse
begot 334, and King Herod 497 winners. A "cock-tail" is a horse not purely
bred, but with only one-eighth or one-sixteenth impure blood in his veins,
yet very few instances have ever occurred of such horses having won a great
race. They are sometimes as fleet for short distances as thoroughbreds, but
as Mr. Robson, the great trainer, asserts, they are deficient in wind, and
cannot keep up the pace. Mr. Lawrence also remarks, "perhaps no instance
has ever occurred of a three-part-bred horse saving his '_distance_' in
running two miles with thoroughbred racers." It has been stated by Cecil,
that when unknown horses, whose parents were not celebrated, have
unexpectedly won great races, as in the case of Priam, they can always be
proved to be descended on both sides, through many generations, from
first-rate ancestors. On the Continent, Baron Cameronn challenges, in a
German veterinary periodical, the opponents of the English race-horse, to
name one good horse on the Continent which has not some English race-blood
in his veins.[22]

With respect to the transmission of the many slight, but {12} infinitely
diversified characters, by which the domestic races of animals and plants
are distinguished, nothing need be said; for the very existence of
persistent races proclaims the power of inheritance.

A few special cases, however, deserve some consideration. It might have
been anticipated, that deviations from the law of symmetry would not have
been inherited. But Anderson[23] states that a rabbit produced in a litter
a young animal having only one ear; and from this animal a breed was formed
which steadily produced one-eared rabbits. He also mentions a b