INTRODUCTION. 
XXV 
a few months the skin begins to shrivel and recede from the shaft, and by 
the return of the usual period of moulting, it no longer encircles the 
feather, which, by these means, and by its own contraction, loosely hangs 
by its extremity alone. It is soon thrust out from the socket by the 
incipient feather, which is fed by a small vein and artery, these draw the 
nutriment, not from the reservoir of colouring matter in the tube, but from 
the body of the bird. The pith, that light, thin, and vascular appearance 
in the tube, and the medullary part, tlie soft, white substance found in the 
shaft of the quill, conduct and ditfuse, from numerous blood-vessels, the 
nourishment over its interior; in the same manner as the umbilical artery 
feeds the infant in the womb. The nutriment ceases, and the blood-vessels 
dry up, when the quill is fully hardened ; and the pith becomes a light 
transparent substance of no further service. As soon as the feather has 
fulfilled its office, it drops at the appointed period, like the one that pre- 
ceded it. In the inspection of birds, their plumage is the first part that 
takes our attention. A dress, combining elegance and lightness with 
strength, comfort with utility, forming a most effectual covering to protect 
the bird against the injuries of heat, and cold, and of a humid sky. If we 
examine its texture, we are struck with astonishment ; if we regard its 
hues, we are lost in surprize ; in the nice adaptation of one part with 
another, in the order and disposition of the layers, in the admirable 
harmony and curious mechanism of the whole of this apparatus, we see 
a conformation and design, infinitely surpassing human contrivance, arid 
which evince the regulating hand of God. This plumage is admirably 
suited to the intended purpose. A soft downy substance first clothes the 
body of the bird; and in those that require, from their habits and manners, 
greater warmth, it is generally of a blackish hue, to absorb and retain the 
heat, and is covered and overspread by various layers of feathers, admirably 
disposed, and in all instances adequate to their necessities and habits of life. 
The males are mostly distinguished for the vivid beauties of their colours, 
which render them more engaging and attracting to the eye than the 
females ; and in the warmer climates, nature has embellished birds in 
E 
