VARIATION UNDER DOMESTICATION. [Chap. I. 



or cultivation, and vary very slightly — perhaps hardly more than in 

 a state of nature. 



Some naturalists have maintained that all variations are con- 

 nected 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, as they may be named, can be pro- 

 pagated 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 the many thousands, 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 spark, by which a mass of combustible 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. 

 With 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 nnd the bones of the leg more, in proportion 

 to the whole skeleton, than do the same bones in the wild-duck ; 

 and this change may be safely attributed to the domestic duck 

 flying much less, and walking more, than its wild parents. The 

 great and inherited development of the udders in cows and goats in 

 countries where they are habitually milked, in comparison with 

 these organs in other countries, is probably another instance of the 

 effects of use. Not one of our domestic animals can be named 

 which has not in some country drooping ears ; and the view which 

 bas 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. 



Many laws regulate variation, some few of which can be dimly 



