| 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 
 plants;" 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,| plants;" 1872 |  | plants," 1869 | 
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| bud variations, 1872 |  | bud-variations, 1869 | 
under culture.  As a single bud out of 
 ..
many 
 thousands,| are far from rare 1872 |  | far from rarely 1869 | 
produced year after year 
 on the same tree under uniform conditions,| thousands, 1872 |  | thousands 1869 | 
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 
 spark, 
by which a mass of 
 ..
 combustible| on the same tree under uniform conditions, 1872 |  | under uniform conditions on the same tree, 1869 | 
matter is ignited, has in determining the nature of the flames. ↑| combustible 1872 |  | bustible 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. | 
 | 
| Changed habits produce an inherited effect, as in the period of 
 the flowering of| 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 | 
plants when transported from one climate to another. 
 With| the flowering of 1869 1872 |  | flowering with 1859 1860 1861 1866 | 
animals 
 the increased use or disuse of parts has had| With 1872 |  | In 1859 1860 1861 1866 1869 | 
a more marked 
 influence; thus| the increased use or disuse of parts has had 1872 |  | it has 1859 1860 1861 1866 |  | they have 1869 | 
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 
 ...| influence; thus 1872 |  | effect; for instance, 1859 1860 1861 1866 1869 | 
this change may be safely attributed to the domestic duck flying much less, and walking more, than its wild 
 parents.| OMIT 1869 1872 |  | I presume that 1859 1860 1861 1866 | 
The great and inherited development of the udders in cows and goats in countries where they are habitually milked, in comparison with 
 ...| parents. 1869 1872 |  | parent. 1859 1860 1861 1866 | 
these organs in other countries, is 
 probably another| OMIT 1872 |  | the state of 1859 1860 1861 1866 1869 | 
instance of the 
 effects| probably another 1866 1869 1872 |  | another 1859 1860 1861 | 
of use.  Not 
 one of our| effects 1866 1869 1872 |  | effect 1859 1860 1861 | 
domestic 
 animals| one of our 1869 1872 |  | a single 1859 1860 1861 1866 | 
can be named which has not in some country drooping ears; and the view 
 which has been suggested| animals 1869 1872 |  | animal 1859 1860 1861 1866 | 
that the drooping is due to the disuse of the muscles of the ear, from the animals 
 ..| which has been suggested 1866 1869 1872 |  | suggested by some authors, 1859 1860 1861 | 
being 
 seldom much alarmed,| ..... 1866 1869 1872 |  | not 1859 1860 1861 | 
seems probable.| seldom much alarmed, 1872 |  | much alarmed by danger, 1859 1860 1861 |  | seldom alarmed by danger, 1866 1869 | 
 |