A slight difference in climate or pasture sometimes slightly affects the
fleece, as has been observed even in different districts in England, and is
well shown by the great softness of the wool brought from Southern
Australia. But it should be observed, as Youatt repeatedly insists, that
the tendency to change may generally be counteracted by careful selection.
M. Lasterye, after discussing this subject, sums up as follows: "The
preservation of the Merino race in its utmost purity at the Cape of Good
Hope, in the marshes of Holland, and under the rigorous climate of Sweden,
furnishes an additional support of this my unalterable principle, that
fine-woolled sheep may be kept wherever industrious men and intelligent
breeders exist."

That methodical selection has effected great changes in several breeds of
sheep no one who knows anything on the subject, entertains a doubt. The
case of the Southdowns, as improved by Ellman, offers perhaps the most
striking instance. Unconscious or occasional selection has likewise slowly
produced a great effect, as we shall see in the chapters on Selection. That
crossing has largely modified some breeds, no one who will study what has
been written on this subject--for instance, Mr. Spooner's paper--will
dispute; but to produce uniformity in a crossed breed, careful selection
and "rigorous weeding," as this author expresses it, are indispensable.
(3/95. 'Journal of R. Agricult. Soc. of England' volume 20 part 2, W.C.
Spooner on cross-Breeding.)

In some few instances new breeds have suddenly originated; thus, in 1791, a
ram-lamb was born in Massachusetts, having short crooked legs and a long
back, like a turnspit-dog. From this one lamb the otter or ancon semi-
monstrous breed was raised; as these sheep could not leap over the fences,
it was thought that they would be valuable; but they have been supplanted