

312 



LAWS OP VARIATION. 



Chap. XXIV. 



spring necessarily stands in any direct relation with the 



of the climate inhabited by the parents 



'0 



On the contrary 



appear 



the same 



hardy and tender varieties of the same species 



ntry. New 



sly arising become fitted to 



thus spontane 



ghtly different climates 



different ways ; firstly, they may have the power either 



as 



cold 



seedlings or when full-grown, of resisting 

 the Moscow pear, or of resisting intense heat, as with some kinds 

 of Pelargonium, or the flowers may withstand severe frost, as 

 with the Forelle pear. Secondly, plants may become adapted 

 to climates widely different from their own, from flowering and 



fruiting either earlier or later 



season. In both these 



the power of acclimatisation by man consists simply 



selection and preservation of 



But without any 



direct intention on his part of securing a hardier variety 



matisation may be 



asciously effected 



by merely raising 



th wards 



tender plants from seed, and by occasionally attempting 

 cultivation further and further no 

 maize, the orange, and the peach. 



How much influence ought to be attributed to inherited habit 



of 



custom 



acclimatisation of animals and plants 



much more difficult question. In many 



hardly have failed to have come into play and complicated 



the result 



It 



is 



that: mountain sheep 



weather and storms of snow which would destroy lowland 

 breeds ; but then mountain sheep have been thus exposed from 

 time immemorial, and all delicate individuals will have been 

 destroyed, and the hardiest preserved. So with the Arrindy 

 silk-moths of China and India; who can tell how far natural 

 selection may have taken a share in the formation of the two 

 races, which are now fitted for such widely different climates ? 

 It seems at first probable that the many fruit-trees which are 



the hot summers and cold winters of North 

 America, in contrast with their poor success under our climate, 

 have become adapted through habit ; but when we reflect on 



so well fitted for 



the multitude of seedling 



and 



ally raised in that country, 



towards 



) would succeed unless born with a fitting con- 

 possible that mere habit may have done nothing 

 acclimatisation. On the other hand, when we 



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