52 VARIATION TJNDEE NATUEE. [Chap. II. 



technical sense, as implying a modification directly due 

 to the physical conditions of life ; and " variations " in 

 this sense are supposed not to be inherited; but who 

 can say that the dwarfed condition of shells in the 

 brackish waters of the Baltic, or dwarfed plants on 

 Alpine summits, or the thicker fur of an animal from 

 far northwards, would not in some cases be inherited 

 for at least a few fenerations ? and in this case I 

 presume that the form would be called a variety. 



It may be doubted whether sudden and considerable 

 deviations of structure such as we occasionally see in 

 our domestic productions, more especially with plants, 

 are ever permanently propagated in a state of nature. 

 Almost every part of every organic being is so beauti- 

 fully related to its complex conditions of life that it 

 seems as improbable that any part should have been 

 suddenly produced perfect, as that a complex machine 

 should have been invented by man in a perfect state. 

 Under domestication monstrosities sometimes occur 

 which resemble normal structures in widely different 

 animals. Thus pigs have occasionally been born 

 with a sort of proboscis, and if any wild species of the 

 same genus had naturally possessed a proboscis, it 

 might have been argued that this had appeared as a 

 monstrosity ; but I have as yet failed to find, after 

 diligent search, cases of monstrosities resembling 

 normal structures in nearly allied forms, and these 

 alone bear on the question. If monstrous forms of 

 this kind ever do appear in a state of nature and are 

 capable of reproduction (which is not always the case), 

 as they occur rarely and singly, their preservation 

 would depend on unusually favourable circumstances. 

 They would, also, during the first and succeeding 



