FEATHERS OF BIRDS. 511 



over the whole of its external surface ; but as it 

 retires towards the root, it leaves a succession of 

 very thin pellucid membranes, in the form of cones, 

 which, when dried, constitute what is termed the pith 

 of the quill. The last remnant of the bulb is seen 

 in the slender ligament which passes through the 

 lower orifice, and preserves the attachment of the 

 feather to the skin. In process of time, this also 

 decays, and the whole feather is cast off, prepara- 

 tory to the formation of another, which in due sea- 

 son is to replace it. All the feathers are in general, 

 moulted annually, or even at shorter periods; and 

 the same complicated process is again begun and 

 completed, by a new matrix produced for the occa- 

 sion, every time a new feather is to be formed. 



It is impossible, on reviewing these curious facts, 

 not to be struck with the admirable art and fore- 

 sight, which are implied in all this long and com- 

 plicated series of operations. While the bird was 

 yet nourished by the fluids of the egg, the ground 

 had already been prepared for its future plumage, 

 and for the formation of instruments of flight. A 

 temporary investment of down is in readiness to 

 shelter the tender chicken from the rude impres- 

 sions of the air, and an apparatus is preparing for 

 the construction of the most refined instruments 

 for clothing and for motion : first the scaffolding, as 

 it may be called, is erected, by the help of which 

 each portion is built up in succession, and in proper 

 order. Nature's next care is to construct the vane, 

 which is the part of the feather most essential to 

 its office : and then to form the shaft, to which the 

 vane is to be affixed, and from which it receives 

 its support : lastly, she forms the barrel of the 



