DIVISIONS OF THE ANIMAL KINGDOM. lv 



to our lakes and ponds, by the mere change of his natural 

 form. 



The common gallinaceous fowls, in the state of nature, 

 live amongst trees, and, when subjugated, still retain the 

 desire to roost on elevated objects. But they can now with 

 difficulty ascend the perches prepared for them ; their abdo- 

 minal viscera having extended, their bodies have enlarged 

 posteriorly, the breast has become wider, and the neck more 

 short, and their wings having become insufficient to support 

 the increased weight of their bodies, they have almost lost 

 the power of flight ; and so changed is their entire conforma- 

 tion, that naturalists can but conjecture from what parent 

 stock they have been derived. 



Besides the effect of increased or diminished supplies of 

 food in modifying the animal form, much is to be ascribed to 

 temperature, humidity, altitude, and, consequently, the rarity 

 or density of the air. The effect of heat is everywhere ob- 

 served, as it modifies the secretions which give colour to the 

 skin, and the degree of covering provided for the protection 

 of the body, whether wool or hair. In the case of the human 

 species, the effects of temperature on the colour of the skin, 

 and, with this, on the colour of the eyes and hair, are sufficient- 

 ly known. We cannot pass from the colder parts of Europe 

 to the warmer, without marking the progressive diversities of 

 colour, from the light complexion of the northern nations, 

 to the swarthy tinge of the Spaniards, Italians, and Greeks ; 

 and when we have crossed the Mediterranean into Africa, 

 the dark colour, which is proper to all the warmer regions of 

 the globe, everywhere meets the eye. The Jews, naturally 

 as fair as the other inhabitants of Syria, become gradually 

 darker, as they have been for a longer or shorter time accli- 

 mated in the warmer countries ; and in the plains of the 

 Ganges, they are as dark as Hindoos. The Portuguese who 

 have been naturalized in the African colonies of their nation, 

 have become entirely black. If we suppose, indeed, the great 

 races of mankind to have been called into existence in differ- 



