80 DIFFICULTIES AND [CHAP. in. 



really so great, that abundant food has not made the 

 Pigeons produce more than their usual two eggs, as 

 well as change their appearance so completely. It 

 ought to make them extend their laying from the dual 

 to the plural number. This would be a less remarkable 

 change than those which are supposed to have taken 

 place. But it never happens. We ought, in truth, to 

 be more thankful than we are for the varied bounty of 

 Providence in creating the Pigeons to be prolific of 

 young, arid to supply an abundance of flesh in their 

 proper regions, while the Fowls are made to offer to us, 

 in profusion, a different kind of aliment. 



In the case of domesticated birds and animals, the 

 science of Comparative Anatomy hesitates to establish 

 the same distinctions that it is made, in the proficient 

 hands of Mr. Yarrell, to determine with the Swans, and 

 by M. Temminck with the Guans, and which, to some 

 minds, it ought to draw between Pigeons, unless the 

 actual process of transition from the Rock Dove to a 

 Fan-tail or Carrier has actually been observed and 

 recorded while going on, and can be repeated whenever 

 Man chooses to set about the task. And students, who 

 are not satisfied with the mere dictum and opinion of a 

 fallible, though learned, authority, have a right to re- 

 quire either documents proving how, when, and where 

 these races were first established, or else the exhibition 

 of a few more zoological results, to make it possible to 

 their belief that any such results ever have been pro- 

 duced in the way asserted. 



I have thus made bold to state a few reasons for 

 historic doubts whether the French savans and their 

 followers are standing on quite sure and impregnable 

 ground, when they derive all these curious races from 



