2O Permanence and Evolution. 



being taken to eliminate the effects of rever- 

 sion. 



Secondly, when these are found, we may to a 

 certain extent generalise so far as to suppose in 

 the same or closely allied natural groups the 

 possibility of a moderately greater amount of 

 change through the same causes acting through 

 longer periods. As to all beyond, we must 

 suppose permanence to prevail, having no reason 

 to think the contrary. Our instances must 

 naturally be sought almost entirely among 

 domestic animals. 



In one chapter of Darwin's "Domestic Animals 

 and Cultivated Plants," he enunciates truths 

 which tend to the overthrow of his whole hypo- 

 thesis. I mean those in which he speaks of the 

 power of inheritance, and especially calls atten- 

 tion to the fact that characters can be " fixed," 

 as for instance when (Vol. II. p. 24, Edition II.) 

 he says that no character is more fleeting than 

 colour, especially in the horse, but that it 



