^be Stor^ of tbe Stem 35 



obtained by beating all the soft parts from the filjres, 

 and pounding the fibres into a kind of felt. 



If leaves, and some kinds of stems, are soaked in 

 water until the soft parts are decayed, this decayed 

 portion can be gently ' brushed from the woody 

 frame-work, and the beautiful structure clearly ex- 

 hibited. 



Cells are not always placed in columns, or straight 

 lines ; they may be sf)iral, or in rings, or in six-sided 

 canals, or in porous sacs laid one against another. 



These interior tissues of the plant serve for circu- 

 lation, for breathing, for the digesting of food, for 

 building up of frame-work and of fleshy parts — as 

 the organs of the body perform such functions for 

 animals. 



The bark and rinds of stems and branches are 

 formed of tougher tissue, hardened by the air, sun, 

 and storms ; it is often spread with a thin varnish- 

 like coating, to protect the inner portions from rain, 

 and from insects. Some stems, as was noted in the 

 previous chapter, are provided with hairs, or fine 

 down ; they look as if dressed in fur jackets. 



Near this rind or bark, lie the sap vessels. If the 

 bark is cut through all about the trunk, the tree will 

 die for lack of circulation of sap. This cutting 

 around of the bark near the base of the trunk is 

 called girdling ; it is a way taken to kill trees which 



