400 THE MECHANICAL FUNCTIONS. 



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, preparato- 

 ry to the formation of another, which, in due season, is to 

 replace it. All the feathers are, in general, moulted annual- 

 ly, or even at shorter periods; and the same complicated 

 process is again begun and completed by a new matrix pro- 

 duced for the occasion, 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 foresight which are 

 implied in all this long and complicated 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 tempora- 

 ry investment of down is in readiness to shelter the tender 

 chicken from the rude impressions of the air, and an 

 apparatus is preparing for the construction of the most re- 

 fined instruments for clothing and for motion: first, the scaf- 

 folding, 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 

 quill, which is prolonged for the purpq^e of converting it 

 into a lever of sufficient length for the mechanical office it 

 has to perform. In proportion as each structure is finished, 

 she neglects not to remove the scaffolding which had been 

 setup as a temporary structure; the membranes, with all 

 their partitions, are carried away, the vascular pulp of the 

 bulb is absorbed, and its place supplied by air, tiius securing 

 the utmost lightness, without any diminution of strength. 

 Is it possible for any rational mind, after meditating upon 

 these facts, to arrive at the persuasion that they are all the 

 mere results of chance? 



