II. 



ON THE TENDENCY OF VARIETIES TO 

 DEPART INDEFINITELY FROM THE 

 ORIGINAL TYPE.* 



Instability of Varieties supposed to prove the permanent 

 distinctness of Species. 



ONE of the strongest arguments which have been ad- 

 duced to prove the original and permanent distinct- 

 ness of species is, that varieties produced in a state of 

 domesticity are more or less unstable, and often have 

 a tendency, if left to themselves, to return to the 

 normal form of the parent species; and this insta- 

 bility is considered to be a distinctive peculiarity of 

 all varieties, even of those occurring among wild 

 animals in a state of nature, and to constitute a pro- 

 vision for preserving unchanged the originally created 

 distinct species. 



In the absence or scarcity of facts and observa- 

 tions as to varieties occurring among wild animals, 

 this argument has had great weight with natural- 

 ists, and has led to a very general and somewhat 



* Written at Ternate, February, 1858; and published in 

 the Journal of the Proceedings of the Linnsean Society for 

 August, 1858. 



