ORDER ACCIPITRES. 115 



volatile character of the feathered race, and the latter of the 

 complexion of the quadrupeds. 



The tension of fibre, the dry temperament, and extreme 

 mobility of the muscles in birds, render their sensibiUty more 

 energetic. Organs so excitable are put in sudden motion by 

 the slightest impressions. Such animals have need of multi- 

 plied sensations . They pass their lives in a perpetual state of 

 agitation and motion. Repose is to them a torment ; for, in 

 proportion as their sensations are more lively, so are they more 

 changeable, as is observable amongst mankind. The birds are 

 of an irritable and nervous constitution : everything animates 

 them to excess. They are ardent, choleric, amorous in the 

 extreme, and quick and impetuous in all their actions. They 

 all sleep but little ; and as for what has been said concerning 

 the immersion of swallows in the bottom of lakes during the 

 winter, and the retreat of quails into caverns, it appears ex- 

 tremely contrary to the nature of those animals. Emigration 

 is the much more natural and probable mode of accounting for 

 their disappearance. 



The extent of sensibility possessed by birds cannot be, as we 

 have already seen, at all traced to the sense of touch, which, 

 from the covering of their bodies, and the hard and osseous 

 character of their beaks and feet, must be extremely obtuse. 

 Laminae, or very callous scales, invest all the toes ; and among 

 a few species only the beak is just barely surrounded at its 

 base with a little naked skin. But from what we have already 

 said concerning the power of vision in birds, it appears evident 

 that their quick sensibility, and extreme vivacity of character, 

 are greatly dependent on the wonderful development of this 

 sense. We may remark, indeed, as a general rule, though 

 perhaps not wholly without exceptions, that a.nimals of very 

 limited power of vision, and still more those which are destitute 

 of sight, are sedentary and inactive. The fishes, which are so 

 lively and agile, have, like the birds, a very extended range of 

 sight; while worms, moUusca, zoophytes, &c. whose gait is 

 groping and slow, are almost all blind, 



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