THE DOMESTIC FOWL. 73 



of any two wild species, that would continue to re- 

 produce offspring, like itself, and not finally revert back 

 to one or other original type. 



As to the great question of the " immutability of 

 species," so closely allied to the investigation of the 

 different varieties of poultry, as far as the limited 

 researches of physiologists and naturalists have gone 

 and they have been confined almost entirely to birds 

 under the control or influence of man I have been 

 led to the conclusion that sub-species, and even varie- 

 ties, are much more permanent, independent, and 

 ancient, than is currently believed at the present day. 

 My conviction is, that the diversities which we see 

 even in the most nearly-allied races of birds, are not 

 produced by any transmuting influence of time, vari- 

 ation or increase of food, change of climate, (except in 

 some instances in their feathers,) nor by hybridization ;* 

 but that each distinct variety, however nearly resem- 

 bling any other, has been produced by a Creative 

 Power. Moreover, facts would seem to prove that 

 hybrids, possessed of the power of reproduction, are 

 even then saved from being barren only by their pro- 

 geny more or less rapidly reverting to the type of one 

 parent or the other ; so that no intermediate race is 

 founded. Things sooner or later go on as they went 

 before, or they cease to go on at all. This is the case 

 with our domestic animals generally ; and is well 

 known to breeders as one of the most inflexible diffi- 



* The prevalence of bright colors in the animals of polar and cold regions is 

 well known, and is ascribed to the influence of climate ; the arctic fox, the 

 polar bear, and the American snow bird, are striking instances. The same 

 character is remarkable in some species which are more darkly colored in 

 warmer situations. A similar fact is also observable in those birds and animals 

 which change their color in the same country, at the winter season, to white- 

 or grey, as the ermine, {Mustela ermina,) and weasel, (M. nivalis,) the varying 

 hare, squirrel, reindeer, the white game bird of Lapland, (Tetrao lagopus,) and 

 the American snow bunting (Emberiza nivulis.) In cold regions, too. the fur 

 and feathers are thicker, and more copious, so as to form a much more effectual 

 defence against the climate than the coarser and rarer textures which are 

 seen in warm countries. 



Difference of food might be naturairy expected to produce considerable cor- 

 responding modifications in the color, form, and size of animals. For instance, 

 oxen become very large and fat when reared for many generations on rich soils, 

 but are distinguished by shortness of the legs ; while, on drier situations, their 

 whole bulk is less, and the limbs more muscular and strong. Some singing birds, 

 too, chiefly of the lark and finch kinds, are known to become gradually black 

 if they are fed on hemp seed alone. 



4 



