CHAPTER I
VARIATION UNDER DOMESTICATION
Unconscious Selection
At the present time, eminent breeders try by methodical selection,
with a distinct object in view, to make a new strain or sub-breed,
superior to anything of the kind in the country. But, for our purpose,
a form of Selection, which may be called Unconscious, and which
results from every one trying to possess and breed from the best
individual animals, is more important. Thus, a man who intends keeping
pointers naturally tries to get as good dogs as he can, and afterwards
breeds from his own best dogs, but he has no wish or expectation of
permanently altering the breed. Nevertheless we may infer that this
process, continued during centuries, would improve and modify any
breed, in the same way as Bakewell, Collins, &c., by this very same
process, only carried on more methodically, did greatly modify, even
during their lifetimes, the forms and qualities of their cattle.
Slow and insensible changes of this kind can never be recognised
unless actual measurements or careful drawings of the breeds in
question have been made long ago, which may serve for comparison. In
some cases, however, unchanged, or but little changed individuals of
the same breed exist in less civilised districts, where the breed
has been less improved. There is reason to believe that King Charles's
spaniel has been unconsciously modified to a large extent since the
time of that monarch. Some highly competent authorities are
convinced that the setter is directly derived from the spaniel, and
has probably been slowly altered from it. It is known that the English
pointer has been greatly changed within the last century, and in
this case the change has, it is believed, been chiefly effected by
crosses with the foxhound; but what concerns us is, that the change
has been effected unconsciously and gradually, and yet so effectually,
that, though the old Spanish pointer certainly came from Spain, Mr.
Borrow has not seen, as I am informed by him, any native dog in
Spain like our pointer.
By a similar process of selection, and by careful training,
English race-horses have come to surpass in fleetness and size the
parent Arabs, so that the latter, by the regulations for the
Goodwood Races, are favoured in the weights which they carry. Lord
Spencer and others have shown how the cattle of England have increased
in weight and in early maturity, compared with the stock formerly kept
in this country. By comparing the accounts given in various old
treatises of the former and present state of carrier and tumbler
pigeons in Britain, India, and Persia, we can trace the stages through
which they have insensibly passed, and come to differ so greatly
from the rock-pigeon.
Youatt gives an excellent illustration of the effects of a course of
selection, which may be considered as unconscious, in so far that
the breeders could never have expected, or even wished, to produce the
result which ensued- namely, the production of two distinct strains.
The two flocks of Leicester sheep kept by Mr. Buckley and Mr. Burgess,
as Mr. Youatt remarks, "have been purely bred from the original
stock of Mr. Bakewell for upwards of fifty years. There is not a
suspicion existing in the mind of any one at all acquainted with the
subject, that the owner of either of them has deviated in any one
instance from the pure blood of Mr. Bakewell's flock, and yet the
difference between the sheep possessed by these two gentlemen is so
great that they have the appearance of being quite different
varieties."
If there exist savages so barbarous as never to think of the
inherited character of the offspring of their domestic animals, yet
any one animal particularly useful to them, for any special purpose,
would be carefully preserved during famines and other accidents, to
which savages are so liable, and such choice animals would thus
generally leave more offspring than the inferior ones; so that in this
case there would be a kind of unconscious selection going on. We see
the value set on animals even by the barbarians of Tierra del Fuego,
by their killing and devouring their old women, in times of dearth, as
of less value than their dogs.
In plants the same gradual process of improvement, through the
occasional preservation of the best individuals, whether or not
sufficiently distinct to be ranked at their first appearance, as
distinct varieties, and whether or not two or more species or races
have become blended together by crossing, may plainly be recognised in
the increased size and beauty which we now see in the varieties of the
heartsease, rose, pelargonium, dahlia, and other plants, when compared
with the older varieties or with their parent-stocks. No one would
ever expect to get a first-rate heartsease or dahlia from the seed
of a wild plant. No one would expect to raise a first-rate melting
pear from the seed of the wild pear, though he might succeed from a
poor seedling growing wild, if it had come from a garden-stock. The
pear, though cultivated in classical times, appears, from Pliny's
description, to have been a fruit of very inferior quality. I have
seen great surprise expressed in horticultural works at the
wonderful skill of gardeners, in having produced such splendid results
from such poor materials; but the art has been simple, and, as far
as the final result is concerned, has been followed almost
unconsciously. It has consisted in always cultivating the best-known
variety, sowing its seeds, and, when a slightly better variety chanced
to appear, selecting it, and so onwards. But the gardeners of the
classical period who cultivated the best pears which they could
procure, never thought what splendid fruit we should eat; though we
owe our excellent fruit in some small degree, to their having
naturally chosen and preserved the best varieties they could
anywhere find.
A large amount of change, thus slowly and unconsciously accumulated,
explains, as I believe, the well-known fact, that in a number of cases
we cannot recognise, and therefore do not know, the wild parent-stocks
of the plants which have been longest cultivated in our flower and
kitchen gardens. If it has taken centuries or thousands of years to
improve or modify most of our plants up to their present standard of
usefulness to man, we can understand how it is that neither Australia,
the Cape of Good Hope, nor any other region inhabited by quite
uncivilised man, has afforded us a single plant worth culture. It is
not that these countries, so rich in species, do not by a strange
chance possess the aboriginal stocks of any useful plants, but that
the native plants have not been improved by continued selection up
to a standard of perfection comparable with that acquired by the
plants in countries anciently civilised.
In regard to the domestic animals kept by uncivilised man, it should
not be overlooked that they almost always have to struggle for their
own food, at least during certain seasons. And in two countries very
differently circumstanced, individuals of the same species, having
slightly different constitutions or structure would often succeed
better in the one country than in the other; and thus by a process
of "natural selection," as will hereafter be more fully explained, two
sub-breeds might be formed. This, perhaps, partly explains why the
varieties kept by savages, as has been remarked by some authors,
have more of the character of true species than the varieties kept
in civilised countries.
On the view here given of the important part which selection by
man has played, it becomes at once obvious, how it is that our
domestic races show adaptation in their structure or in their habits
to man's wants or fancies. We can, I think, further understand the
frequently abnormal characters of our domestic races, and likewise
their differences being so great in external characters, and
relatively so slight in internal parts or organs. Man can hardly
select, or only with much difficulty, any deviation of structure
excepting such as is externally visible; and indeed he rarely cares
for what is internal. He can never act by selection, excepting on
variations which are first given to him in some slight degree by
nature. No man would ever try to make a fantail till he saw a pigeon
with a tail developed in some slight degree in an unusual manner, or a
pouter till he saw a pigeon with a crop of somewhat unusual size;
and the more abnormal or unusual any character was when it first
appeared, the more likely it would be to catch his attention. But to
use such an expression as trying to make a fantail, is, I have no
doubt, in most cases, utterly incorrect. The man who first selected
a pigeon with a slightly larger tail, never dreamed what the
descendants of that pigeon would become through long-continued, partly
unconscious and partly methodical, selection. Perhaps the
parent-bird of all fantails had only fourteen tail-feathers somewhat
expanded, like the present Java fantail, or like individuals of
other and distinct breeds, in which as many as seventeen tail-feathers
have been counted. Perhaps the first pouter-pigeon did not inflate its
crop much more than the turbit now does the upper part of its
oesophagus,- a habit which is disregarded by all fanciers, as it is
not one of the points of the breed.
Nor let it be thought that some great deviation of structure would
be necessary to catch the fancier's eye: he perceives extremely
small differences, and it is in human nature to value any novelty,
however slight, in one's own possession. Nor must the value which
would formerly have been set on any slight differences in the
individuals of the same species, be judged of by the value which is
now set on them, after several breeds have fairly been established.
I is known that with pigeons many slight variations now occasionally
appear, but these are rejected as faults or deviations from the
standard of perfection in each breed. The common goose has not given
rise to any marked varieties; hence the Toulouse and the common breed,
which differ only in colour, that most fleeting of characters, have
lately been exhibited as distinct at our poultry shows.
These views appear to explain what has sometimes been noticed-
namely, that we know hardly anything about the origin or history of
any of our domestic breeds. But, in fact, a breed, like a dialect of a
language, can hardly be said to have a distinct origin. man
preserves and breeds from an individual with some slight deviation
of structure, or takes more care than usual in matching his best
animals, and thus improves them, and the improved animals slowly
spread in the immediate neighbourhood. But they will as yet hardly
have a distinct name, and from being only slightly valued, their
history will have been disregarded. When further improved by the
same slow and gradual process, they will spread more widely, and
will be recognised as something distinct and valuable, and will then
probably first receive a provincial name. In semi-civilised countries,
with little free communication, the spreading of a new sub-breed would
be a slow process. As soon as the points of value are once
acknowledged, the principle, as I have called it, of unconscious
selection will always tend,- perhaps more at one period than at
another, as the breed rises or falls in fashion,- perhaps more in
one district than in another, according to the state of civilisation
of the inhabitants,- slowly to add to the characteristic features of
the breed, whatever they may be. But the chance will be infinitely
small of any record having been preserved of such slow, varying, and
insensible changes.
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