8 PBATHEES 



for it is in the flight feathers that the qualities of 

 strength and cohesion are brought to highest perfection. 



Feathers, like the claws, the spurs, and the bill of a 

 bird, the hooves, horns, and nails of a mammal, and the 

 scales of fishes, are horny products of the epidermal 

 cells of the skin. There lies before me a flight 

 feather from a woodpigeon's wing. It consists of three 

 principal parts — the quill or calamus, the shaft or 

 rhachis, and the outer and inner webs. 



The quill is hollow, and more or less transparent. If 

 it is held up against the light a series of opaque objects 

 will be seen occupying the interior of the cylinder as 

 far as its junction with the solid shaft. Remove one 

 side of the quill with a sharp penknife, and the opaque 

 objects will appear as a string of little colourless caps 

 consisting of very thin horny flakes. There are fourteen 

 of these caps in the feather before me; they appear 

 to be functionless — waste products of growth ; but 

 German ornithologists dignify them by the name of 

 die Seele, ' the soul ' of the feather. 



The quill is a hollow cylinder, but the shaft which it 

 supports is solid, quadrangular in transverse section, 

 formed externally of strong horny substance and filled 

 with dense white pith. It has a well-marked furrow along 

 the under side and tapers to an extremely fine point. 



Thus far the structure of this feather is fairly simple, 

 combining the maximum of strength with a minimum 

 of weight and material. The outer and inner webs are 

 of far more delicate and complex character. They are 

 composed of hundreds of rami, termed in English, not 

 very appropriately, 'barbs.' Those of the outer or 



