THE VEGETABLE AND ANIMAL KINGDOMS. 153 



now ascertained that these are variable under particular con- 

 ditions as to food. It has been tried with confined birds ; and 

 even in a wild state there occur individuals strangely modified in 

 this respect, the magpie, woodpecker, and rook, having all been 

 found with the crossed mandibles of the loxia. 1 Look also at 

 the changes from the wild animals to those domesticated ones 

 which are known to be descended from them. "When the 

 eggs of the wild goose," says Professor Low, " are taken, and 

 the young are supplied with food in unlimited quantity, the 

 result is remarkable. The intestines, and with them the ab- 

 domen, become so much enlarged, that the animal nearly loses 

 the power of flight, and the powerful muscles which enabled 

 him in a wild state to take such flights, become feeble from 

 disease, and his long wings are rendered unserviceable. The 

 beautiful bird that outstripped the flight of the eagle, is now a 

 captive without a chain." Another change is the transition 

 from grey to white plumage. In the domestication of the pig, 

 the author last quoted admits that there are reductions of the 

 number of teeth, and variations of the number of the dorsal, 

 lumbar, sacral, and caudal vertebrae, producing differences 

 greater than what are usually regarded as sufficient to consti- 

 tute species. But the most striking observations on this sub- 

 ject are those of M. Roulin, made during a residence of several 

 years in Columbia, relative to the races which had been intro- 

 duced there in a domesticated state by the early voyagers, and 

 allowed to run wild during the three centuries which have 

 since elapsed. As an example, the hog : " Wandering all day 

 in the wood, this animal has lost nearly all marks of servitude ; 

 its ears have become erect, its head broadened, and raised at 

 the upper part, and its colour has been rendered permanent." 

 It has, in short, returned to a strict resemblance to the wild 

 boar of France. The cow, also, from the cessation of the prac- 

 tice of milking, has lost the abundant flow of milk which is 

 found in her species in Europe : to get milk from her at all, 

 it is necessary that her calf should be left with her. M. Roulin 

 arrived at the following conclusions : that animals naturalized 

 in new countries undergo durable changes, bringing their 

 organization into accordance with the climates in which they 

 are destined to live ; and that habits of independence soon 

 make the domestic species resume the characters of the wild 

 species from which they have sprung. We have here, it will 



1 Magazine of Natural History, vii. 57. 



