The Variation of Animals and Plants under Domestication, vol 1 | Page 7

has no
power of altering the absolute conditions of life; he cannot change the
climate of any country; he adds no new element to the soil; but he can
remove an animal or plant from one climate or soil to another, and give
it food on which it did not subsist in its natural state. It is an error to
speak of man "tampering with nature" and causing variability. If a man
drops a piece of iron into sulphuric acid, it cannot be said strictly that
he makes the sulphate of iron, he only allows their elective affinities to
come into play. If organic beings had not possessed an inherent
tendency to vary, man could have done nothing. (Introduction/2. M.
Pouchet has recently ('Plurality of Races' English Translation 1864
page 83 etc.) insisted that variation under domestication throws no light
on the natural modification of species. I cannot perceive the force of his
arguments, or, to speak more accurately, of his assertions to this effect.)
He unintentionally exposes his animals and plants to various conditions
of life, and variability supervenes, which he cannot even prevent or
check. Consider the simple case of a plant which has been cultivated
during a long time in its native country, and which consequently has
not been subjected to any change of climate. It has been protected to a
certain extent from the competing roots of plants of other kinds; it has
generally been grown in manured soil; but probably not richer than that
of many an alluvial flat; and lastly, it has been exposed to changes in its
conditions, being grown sometimes in one district and sometimes in
another, in different soils. Under such circumstances, scarcely a plant
can be named, though cultivated in the rudest manner, which has not
given birth to several varieties. It can hardly be maintained that during
the many changes which this earth has undergone, and during the
natural migrations of plants from one land or island to another, tenanted
by different species, that such plants will not often have been subjected
to changes in their conditions analogous to those which almost
inevitably cause cultivated plants to vary. No doubt man selects

varying individuals, sows their seeds, and again selects their varying
offspring. But the initial variation on which man works, and without
which he can do nothing, is caused by slight changes in the conditions
of life, which must often have occurred under nature. Man, therefore,
may be said to have been trying an experiment on a gigantic scale; and
it is an experiment which nature during the long lapse of time has
incessantly tried. Hence it follows that the principles of domestication
are important for us. The main result is that organic beings thus treated
have varied largely, and the variations have been inherited. This has
apparently been one chief cause of the belief long held by some few
naturalists that species in a state of nature undergo change.
I shall in this volume treat, as fully as my materials permit, the whole
subject of variation under domestication. We may thus hope to obtain
some light, little though it be, on the causes of variability,--on the laws
which govern it, such as the direct action of climate and food, the
effects of use and disuse, and of correlation of growth,--and on the
amount of change to which domesticated organisms are liable. We shall
learn something of the laws of inheritance, of the effects of crossing
different breeds, and on that sterility which often supervenes when
organic beings are removed from their natural conditions of life, and
likewise when they are too closely interbred. During this investigation
we shall see that the principle of Selection is highly important.
Although man does not cause variability and cannot even prevent it, he
can select, preserve, and accumulate the variations given to him by the
hand of nature almost in any way which he chooses; and thus he can
certainly produce a great result. Selection may be followed either
methodically and intentionally, or unconsciously and unintentionally.
Man may select and preserve each successive variation, with the
distinct intention of improving and altering a breed, in accordance with
a preconceived idea; and by thus adding up variations, often so slight as
to be imperceptible by an uneducated eye, he has effected wonderful
changes and improvements. It can, also, be clearly shown that man,
without any intention or thought of improving the breed, by preserving
in each successive generation the individuals which he prizes most, and
by destroying the worthless individuals, slowly, though surely, induces
great changes. As the will of man thus comes into play, we can
understand how it is that domesticated breeds show adaptation to his

wants and pleasures. We can further understand how it is that domestic
races of animals and