THE ORIGIN OF SPECIES. 27 



and whether it would endure other climates? Has the little 

 variability of the ass or Guinea-fowl, or the small power of en- 

 durance of warmth by the reindeer, or of cold by the common 

 camel, prevented their domestication? I cannot doubt that if 

 other animals and plants, equal in number to our domesticated 

 productions, and belonging to equally diverse classes and coun- 

 tries, were taken from a state of nature, and could be made to 

 breed for an equal number of generations under domestication, 

 they would vary on an average as largely as the parent species 

 of our existing domesticated productions have varied." 



As to amount of variation, there is the common 

 remark of naturalists that the varieties of domesti- 

 cated plants or animals often differ more widely than 

 do the individuals of distinct species in a wild state : 

 and even in l^ature the individuals of some species are 

 known to vary to a degree sensibly wider than that 

 which separates related species. In' his instructive 

 section on the breeds of the domestic pigeon, our au- 

 thor remarks that " at least a score of pigeons might 

 be chosen which if shown to an ornithologist, and he 

 were told that they were wild birds, would certainly 

 be ranked by him as well-defined species. Moreover, 

 I do not believe that any ornithologist would place 

 the English carrier, the short-faced tumbler, the runt, 

 the barb, pouter, and fantail, in the same genus ; more 

 especially as in each of these breeds several truly- 

 inherited sub-breeds, or species, as he might have 

 called them, could be shown him." That this is not 

 a case like that of dogs, in which probably the blood of 

 more than one species is mingled, Mr. Darwin proceeds 

 to show, adducing cogent reasons for the common 

 opinion that all have descended from the wild rock- 

 pigeon. Then follow some suggestive remarks : 



