VARIATION UNDER DOMESTICATION. 9 



having their reproductive system so seriously affected by 

 unperceived causes as to fail to act, we need not be surprised 

 at this system, when it does act under confinement, acting 

 irregularly, and producing offspring somewhat unlike their 

 parents. I may add that as some organisms breed freely 

 under the most unnatural conditions — for instance, rabbits 

 and ferrets kept in hutches — showing that their reproduc- 

 tive organs are not easily affected ; so will some animals and 

 plants withstand domestication or 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 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 propagated by 

 grafts, offsets, etc., and sometimes by seed. They occur 

 rarely under nature, but are far from rare under culture. 

 As a single bud out of 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 wivh the nature of the organism in determining 

 each particular form of variation ; perhaps of not more im- 

 portance 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 and the bones of the leg more, in proportion to the 

 whole skeleton, than do the same bones in the wild duck » 



