SECT. XXI. WOODY FIBRE. 4-53 



SECTION XXI. 

 Woody Fibre. 



THE principal body of the root, stem, and 

 branches of trees, is designated by the appellation 

 of Wood. But the term is too general for the pur- 

 pose of analytical distinction, as the part designated 

 by it often includes the greater part of the sub- 

 stances that bave been already enumerated. It 

 remains therefore to be ascertained whether there 

 exists in the plant any individual substance different 

 from those already described, and constituting more 

 immediately the fabric of the wood. 



If a piece of wood is well dried and digested, HOW pro- 

 first in water and then in alcohol or such other sol- cured * 

 vent as shall produce no violent effects upon the 

 insoluble parts ; and if the digestion is continued 

 till the liquid is no longer coloured, and dissolves no 

 more of the substance of the plant, there remains 

 behind a sort of vegetable skeleton, which consti- 

 tutes the basis of the wood, and whicb has been 

 denominated Woody Fibre. It is composed of 

 bundles of longitudinal threads, which are divisible 

 into others still smaller. It is somewhat trans- Properties, 

 parent. It is without taste and smell, and is not 

 altered by exposure to the atmosphere. It is inso- 

 luble in water and alcohol; but the fixed alkalies 

 decompose it with the assistance of heat. When 

 heated in the open air it blackens without melting 



