204 VEETEBRATES. 



ment, and diffusing that nonrishment over the whole frame. 

 When, however, the quill has come to its full growth, and requinss 

 no. further nourishment, the vein and artery become less and less, 

 till at last the little opening by which they communicated with 

 the quill becomes wholly obliterated ; and the quill, thus deprived, 

 continues in its socket for some months, till in the end it shrinks, 

 and leaves room for a repetition of the same process of nature as 

 before. 



The moulting season commonly obtains from the end of 

 summer to the middle of autumn. The bird continues to struggle 

 with this malady during the winter ; and nature has kindly pro- 

 vided, that when there are the fewest provisions, that then the 

 animal's appetite shall be least craving. At the beginning of 

 spring, when food begins again to be plentiful, the animal's 

 strength and vigor return. It is then that the abundance of 

 provisions, aided by the mildness of the season, incite it to love, 

 and all nature seems teeming with life, and disposed to con- 

 tinue it. 



