The Principles of Breeding | Page 9

and ripening in seventy to ninety days when carried
southward, gradually enlarges in the whole plant until it may be grown
twelve feet high and upwards, and requires one hundred and fifty days
to ripen its seed. A southern variety brought northward, gradually
dwindles in size and ripens earlier until it reaches a type specially fitted

to its latitude.
Variation, although the same in kind, is greater in degree, among
domesticated plants than among animals. From the single wild variety
of the potato as first discovered and taken to Europe, have sprung
innumerable sorts. Kemp, in his work on Agricultural Physiology, tells
us, that on the maritime cliffs of England, there exists a little plant with
a fusiform root, smooth glaucous leaves, flowers similar to wild
mustard and of a saline taste. It is called by botanists, Brassica
oleracea. By cultivation there have been obtained from this
insignificant and apparently useless plant--
1st, all borecoles or kails, 12 varieties or more. 2d, all cabbages having
heart. 3d, the various kinds of Savoy cabbages. 4th, Brussels sprouts.
5th, all the broccolis and cauliflowers which do not heart. 6th, the rape
plant. 7th, the ruta baga or Swedish turnip. 8th, yellow and white
turnips. 9th, hybrid turnips. 10th, kohl rabbi.
Similar examples are numerous among our common useful plants, and
among flowers the dahlia and verbena furnish an illustration of
countless varieties, embracing numberless hues and combinations of
color, from purest white through nearly all the tints of the rainbow to
almost black, of divers hights too, and habits of growth, springing up
under the hand of cultivation in a few years from plants which at first
yielded only a comparatively unattractive and self-colored flower. In
brief, it may be said, that nearly or quite all the choicest productions
both of our kitchen and flower gardens are due to variations induced by
cultivation in a course of years from plants which in their natural
condition would scarcely attract a passing glance.
We cannot say what might have been the original type of many of our
domestic animals, for the inquiry would carry us beyond any record of
history or tradition regarding it, but few doubt that all our varieties of
the horse, the ox, the sheep and the dog, sprang each originally from a
single type, and that the countless variations are due to causes
connected with their domestication. Of those reclaimed within the
period of memory may be named the turkey. This was unknown to the
inhabitants of the old continent until discovered here in a wild state.

Since then, having been domesticated and widely disseminated, it now
offers varieties of wide departure from the original type, and which
have been nurtured into self-sustaining breeds, distinguished from each
other by the possession of peculiar characteristics.
Among what are usually reckoned the more active causes of variation
may be named climate, food and habit.
Animals in cold climates are provided with a thicker covering of hair
than in warmer ones. Indeed, it is said that in some of the tropical
provinces of South America, there are cattle which have an extremely
rare and fine fur in place of the ordinary pile of hair. Various other
instances could be cited, if necessary, going to show that a beneficent
Creator has implanted in many animals, to a certain extent, a power of
accommodation to the circumstances and conditions amid which they
are reared.
The supply of food, whether abundant or scanty, is one of the most
active cases of variation known to be within the control of man. For
illustration of its effect, let us suppose two pairs of twin calves, as
nearly alike as possible, and let a male and a female from each pair be
suckled by their mothers until they wean themselves, and be fed always
after with plenty of the most nourishing food; and the others to be fed
with skimmed milk, hay tea and gruel at first, to be put to grass at two
months old, and subsequently fed on coarse and innutritious fodder. Let
these be bred from separately, and the same style of treatment kept up,
and not many generations would elapse before we had distinct varieties,
or breeds, differing materially in size, temperament and time of coming
to maturity.
Suppose other similar pairs, and one from each to be placed in the
richest blue-grass pastures of Kentucky, or in the fertile valley of the
Tees; always supplied with abundance of rich food, these live
luxuriously, grow rapidly, increase in hight, bulk, thickness, every way,
they early reach the full size which they are capable of attaining;
having nothing to induce exertion, they become inactive, lazy, lethargic
and fat. Being bred from, the progeny resemble the parents, "only more
so." Each generation acquiring more firmly and fixedly the

characteristics induced