Permanence and Evolution. 13 



but genera, if properly established, will be found 

 to differ not only more than species, but in 

 different respects (see Wigand, Vol. I.), and 

 so species as compared with varieties, if the 

 distinction can be maintained. Each case must 

 stand by itself. The burden of proof must 

 always lie on the asserter of mutability, for the 

 permanence of the forms of organised nature 

 that which is first impressed upon the casual 

 observer, and that which additional inspection 

 only serves more and more thoroughly to 

 demonstrate. Granting that it is proved that 

 colour can vary independently of reversion, 

 this proves nothing as to the shape of the limbs 

 nor that last as to the dental formula. 



Darwin says that some authors have asserted 

 that an important part never varies, and that 

 the same authors rank only such parts as 

 important as never vary ; but even so there 

 would be no arguing in a circle, for at any 

 rate we should be told that there were some 



