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are far from rare 1872
far from rarely 1869

on the same tree under uniform conditions, 1872
under uniform conditions on the same tree, 1869

←Subtitle not present 1859 1860 1861 1866 1869 1872
9 blocks not present in 1869 1872; present in 1859 1860 1861 1866
Sterility has been said to be the bane of horticulture; but on this view we owe variability to the same cause which produces sterility; and variability is the source of all the choicest productions of the garden. I may add, that as some organisms will breed most freely under the most unnatural conditions (for instance, the rabbit and ferret kept in hutches), showing that their reproductive system has not been thus affected; so will some animals and plants withstand domestication or cultivation, and vary very slightly — perhaps hardly more than in a state of nature. A long list could easily be given of "sporting plants;" by this term gardeners mean a single bud or offset, which suddenly assumes a new and sometimes very different character from that of the rest of the plant. Such buds can be propagated by grafting, &c., and sometimes by seed. These "sports" are extremely rare under nature, but far from rare under cultivation; and in this case we see that the treatment of the parent has affected a bud or offset, and not the ovules or pollen. But it is the opinion of most physiologists that there is no essential difference between a bud and an ovule in their earliest stages of formation; so that, in fact, "sports" support my view, that variability may be largely attributed to the ovules or pollen, or to both, having been affected by the treatment of the parent prior to the act of conception. These cases anyhow show that variation is not necessarily connected, as some authors have supposed, with the act of generation. Seedlings from the same fruit, and the young of the same litter, sometimes differ considerably from each other, though both the young and the parents, as Müller has remarked, have apparently been exposed to exactly the same conditions of life; and this shows how unimportant the direct effects of the conditions of life are in comparison with the laws of reproduction, and of growth, and of inheritance; for had the action of the conditions been direct, if any of the young had varied, all would probably have varied in the same manner. To judge how much, in the case of any variation, we should attribute to the direct action of heat, moisture, light, food, &c., is most difficult: my impression is, that with animals such agencies have produced very little direct effect, though apparently more in the case of plants.

1 blocks not present in 1866 1869 1872; present in 1859 1860 1861
Under this point of view, Mr. Buckman's recent experiments on plants seem extremely valuable.

Effects of Habit and of the Use or Disuse of Parts; Correlated Variation; Inheritance. 1872
Effects of Habit; Correlation of Growth; Inheritance. 1866
Effects of Habit; Correlated Variation; Inheritance. 1869

Changed habits produce an inherited effect, 1872
Habit also has a decided influence, 1859 1860 1861 1866
Habits are inherited and have a decided influence; 1869

the flowering of 1869 1872
flowering with 1859 1860 1861 1866

the increased use or disuse of parts has had 1872
it has 1859 1860 1861 1866
they have 1869

influence; thus 1872
effect; for instance, 1859 1860 1861 1866 1869

OMIT 1869 1872
I presume that 1859 1860 1861 1866

OMIT 1872
the state of 1859 1860 1861 1866 1869

one of our 1869 1872
a single 1859 1860 1861 1866

which has been suggested 1866 1869 1872
suggested by some authors, 1859 1860 1861

seldom much alarmed, 1872
much alarmed by danger, 1859 1860 1861
seldom alarmed by danger, 1866 1869

cultivation, and vary very slightly — perhaps hardly more than in a state of nature.
Some naturalists have maintained that all variations are connected with the act of sexual reproduction; but this is certainly an error; for I have given in another work a long list of "sporting
as they are called by gardeners; — that is, of plants which have suddenly produced a single bud with a new and sometimes widely different character from that of the other buds on the same plant. These
bud variations,
as they may be named, can be propagated by grafts, offsets, &c., and sometimes by seed. They occur rarely under nature, but are far from rare under culture. As a single bud out of
produced year after year on the same tree under uniform conditions, has been known suddenly to assume a new character; and as buds on distinct trees, growing under different conditions, have sometimes yielded nearly the same variety — for instance, buds on peach-trees producing nectarines, and buds on common roses producing moss-roses — we clearly see that the nature of the conditions is of
subordinate importance in comparison with the nature of the organism in determining each particular form of variation; —
perhaps of
not more importance than the nature of the
by which a mass of
matter is ignited, has in determining the nature of the flames.
Effects of Habit and of the Use or Disuse of Parts; Correlated Variation; Inheritance.
Changed habits produce an inherited effect, as in the period of the flowering of plants when transported from one climate to another.
animals the increased use or disuse of parts has had a more marked influence; thus I find in the domestic duck that the bones of the wing weigh less and the bones of the leg more, in proportion to the whole skeleton, than do the same bones in the wild-duck; and OMIT this change may be safely attributed to the domestic duck flying much less, and walking more, than its wild
The great and inherited development of the udders in cows and goats in countries where they are habitually milked, in comparison with OMIT these organs in other countries, is
probably another
instance of the
of use. Not one of our domestic
can be named which has not in some country drooping ears; and the view which has been suggested that the drooping is due to the disuse of the muscles of the ear, from the animals
being seldom much alarmed, seems probable.
There are
variation, some few of which can