BIRDS IN GENERAL. 5 



necessity of its consumption. Their very flesh 

 contracts a flavour from it, which renders it in 

 some very rancid, so as to make it utterly unfit for 

 food ; however, though it injures the flesh, it 

 improves the feathers for all the domestic pur- 

 poses to which they are usually converted. 



Nor are the feathers with which birds are co- 

 vered less an object of admiration. The shaft of 

 every feather is made proportionably strong ; but 

 hollow below for strength and lightness, and 

 above filled with a pith to feed the growth of the 

 vane or beard that springs from the shaft of the 

 feather on either side. All these feathers are 

 placed generally according to their length and 

 strength, so that the largest and strongest feathers 

 in flight have the greatest share of duty. The 

 vane, or beard of the feather, is formed with 

 equal "contrivance and care. It consists not of 

 one continued membrane, because if this were 

 broken, it could not easily be repaired ; but it is 

 composed of many layers, each somewhat in itself 

 resembling a feather, and lying against each other 

 in close conjunction. Towards the shaft of the 

 feather, these layers are broad, and of a semicir- 

 cular form, to serve for strength, and for the 

 closer grafting them one against another when 

 in action. Towards the outer part of the vane, 

 these layers grow slender and taper, to be more 

 light. On their under side they are thin and 

 smooth, but their upper outer edge is parted into 

 two hairy edges, each side having a different sort 

 of hairs, broad at bottom, and slender and beard- 

 ed above. By this mechanism the hooked beards 



