remarked, with respect to the sheep of parts of Yorkshire, that as
they generally belong to poor people, and are mostly _in small lots_,
they never can be improved. On the other hand, nurserymen, from
raising large stocks of the same plants, are generally far more
successful than amateurs in getting new and valuable varieties. The
keeping of a large number of individuals of a species in any country
requires that the species should be placed under favourable conditions
of life, so as to breed freely in that country. When the individuals of
any species are scanty, all the individuals, whatever their quality may
be, will generally be allowed to breed, and this will effectually
prevent selection. But probably the most important point of all, is,
that the animal or plant should be so highly useful to man, or so much
valued by him, that the closest attention should be paid to even the
slightest deviation in the qualities or structure of each individual.
Unless such attention be paid nothing can be effected. I have seen it
gravely remarked, that it was most fortunate that the strawberry began
to vary just when gardeners began to attend closely to this plant. No
doubt the strawberry had always varied since it was cultivated, but the
slight varieties had been neglected. As soon, however, as gardeners
picked out individual plants with slightly larger, earlier, or better
fruit, and raised seedlings from them, and again picked out the best
seedlings and bred from them, then, there appeared (aided by some
crossing with distinct species) those many admirable varieties of the
strawberry which have been raised during the last thirty or forty
years.
In the case of animals with separate sexes, facility in preventing
crosses is an important element of success in the formation of new
races, at least, in a country which is already stocked with other
races. In this respect enclosure of the land plays a part. Wandering
savages or the inhabitants of open plains rarely possess more than one
breed of the same species. Pigeons can be mated for life, and this is a
great convenience to the fancier, for thus many races may be kept true,
though mingled in the same aviary; and this circumstance must have
largely favoured the improvement and formation of new breeds. Pigeons,
I may add, can be propagated in great numbers and at a very quick rate,
and inferior birds may be freely rejected, as when killed they serve
for food. On the other hand, cats, from their nocturnal rambling
habits, cannot be matched, and, although so much valued by women and
children, we hardly ever see a distinct breed kept up; such breeds as
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