VARIATION UNDER DOMESTICATION 71 



eons can be mated for life, and ■.his is a great conven- 

 ience to the fancier, for tlius many races may be im- 

 proved and kept true, though mingled in the same 

 aviary; and this circumstance must have largely fa- 

 vored the formation of new breeds. Pigeons, I may 

 add, can be propagated in great numbers and at a very 

 quick rate, and inferior birds may be freely rejected, 

 as when killed they serve for food. On the other hand, 

 cats, from their nocturnal rambling habits, cannot be ' 

 easily matched, and, although so much valued by women 

 and children, we rarely see a distinct breed long kept ^ 

 up; such breeds as we do sometimes see are almost ^ 

 always imported from some other country. Although I 

 do not doubt that some domestic animals vary less than 

 others, yet the rarity or absence of distinct breeds of the 

 cat, the donkey, peacock, goose, etc., may be attributed 

 in main part to selection not having been brought into 

 play: in cats, from the diflficulty in pairing them; in 

 donkeys, from only a few being kept by poor people, 

 and little attention paid to their breeding; for recently 

 in certain parts of Spain and of the United States this 

 animal has been surprisingly modified and improved by 

 careful selection: in peacocks, from not being very easily 

 reared and a large stock not kept: in geese, from being 

 valuable only for two purposes, food and feathers, and 

 more especially from no pleasure having been felt in the 

 display of distinct breeds; but the goose, under the con- 

 ditions to which it is exposed when domesticated, seems 

 to have a singularly inflexible organization, though it has 

 varied to a slight extent, as I have elsewhere described. 

 Some authors have maintained that the amount of 

 variation in our domestic productions is soon reached, 



