Chap. I. 
tTNDEK DOMESTICATION. 
15 
revert in some of tlieir characters to ancestral forms, it 
seems to me not improbable, that if we could succeed in 
naturalising, or were to cultivate, during many genera¬ 
tions, the several races, for instance, of the cabbage, in 
very poor soil (in which case, however, some effect would 
have to be attributed to the direct action of the poor 
soil), that they would to a large extent, or even wholly, 
revert to the wild aboriginal stock* Whether or not the 
experiment would succeed, is not of great importance 
for our line of argument; for by the experiment itself 
the conditions of life are changed. If it could be shown 
that our domestic varieties manifested a strong tendency 
to reversion,^—^that is, to lose their acquired characters, 
whilst kept under the same conditions, and whilst kept 
in a considerable body, so that free intercrossing might 
check, by blending together, any slight deviations in 
their structure, in such case, I grant that we could 
deduce nothing from domestic varieties in regard to 
species. But there is not a shadow of evidence in favour 
of this view: to assert that we could not breed our cart 
and race-horses, long and short-horned cattle, and poultry 
of various breeds, and esculent vegetables, for an almost 
infinite number of generations, would be opposed to all 
experience. I may add, that when under nature the 
conditions of life do change, variations and reversions 
of character probably do occur; but natural selection, 
as will hereafter be explained, will determine how far 
the new characters thus arising shall be preserved. 
When we look to the hereditary varieties or races of 
our domestic animals and plants, and compare them 
with closely allied species, we generally perceive in 
each domestic race, as already remarked, less uniformity 
of character than in true species. Domestic races of 
the same species, also, often have a somewhat monstrous 
character; by which 1 mean, that, although differing 
