284 BIOLOGY. [Book hi. 



refuge and renews itself on the surface, and these two regions 

 are bound together by a graduated succession of layers, more 

 vitalized in proportion as they approach the bark, more dead in 

 proportion as they approach the centre. 



NOTE. 



The Freneli word auMer expresses better than any English word the white, 

 fresh tender wood between the body of the tree and the baik. — Translator. 



