Chap. VI. MANNER OF FORMATION OF RACES. 223 



countries, such as Sierra Leone, the Malaj; archipelago, and 

 Madeira, they are exposed to new conditions of life ; and 

 apparently in consequence vary in a somewhat greater degree. 

 When closely confined, either for the pleasure of watching 

 them, or to prevent their straying, they must be exposed, 

 even in their native climate, to considerably different con- 

 ditions : for they cannot obtain their natural diversity of 

 food; and, what is probably more important, they axe 

 abundantly fed, whilst debarred from taking much exercise. 

 Under these circumstances we might expect to find, from the 

 analogy of all other domesticated animals, a greater amount 

 of individual variability than with the wild pigeon ; and this 

 is the case. The want of exercise apparently tends to reduce 

 the size of the feet and organs of flight ; and then, from the 

 law of correlation of growth, the beak apparently becomes 

 affected. From what we now see occasionally taking place in 

 our aviaries, we may conclude that sudden variations or 

 sports, such as the appearance of a crest of feathers on the 

 head, of feathered feet, of a new shade of colour, of an addi- 

 tional feather in the tail or wing, would occur at rare intervals 

 during the many centuries which have elapsed since the pigeon 

 was first domesticated. At the present day such " sports " 

 are generally rejected as blemishes ; and there is so much 

 mystery in the breeding of pigeons that, if a valuable sport 

 did occur, its history would often be concealed. Before the 

 last hundred and fifty years, there is hardly a chance of the 

 history of any such sport having been recorded. But it by 

 no means follows from this that such sports in former times, 

 when the pigeon had undergone miich less variation, would, 

 have been rejected. We are profoundly ignorant of the cause 

 of each sudden and apparently spontaneous variation, as well 

 as of the infinitely numerous shades of difference between the 

 birds of the same family. But in a future chapter we shall 

 see that all such variations appear to be the indirect result of 

 changes of some kind in the conditions of life. 



Hence, after a long course of domestication, we might 

 expect to see in the pigeon much individual variabilit}^. and 

 occasional sudden variations, as well as slight modifications 

 from the lessened use of certain parts, together with the 



