Chemistry, composition, and 

 derived products of wood 



jJThe fundamental facts of wood as a 

 ™ibstance must ultimately determine 

 its possibilities as well as its limitations 

 in use. The chemical composition of 

 wood, the arrangement of the constit- 

 uent parts in the wood cells, and the 

 variation of all such characteristics 

 according to species and growth con- 

 ditions are investigated for the aid and 

 insight they afford in all fields of wood 

 research — in silvicultural control of the 

 material and its properties, in its selec- 

 tion, its seasoning and handling, its 

 impregnation with preservatives, its use 

 in construction, and its conversion into 

 pulp and derivative products of all 

 types. ■*•* 



Microstructure 



All wood is composed of cells, and 

 visible under higher magnifications are 

 smaller structural units. These sub- 

 divisions are being carefully explored. 

 The cell walls are made up of concentric 

 layers, which in turn are composed of 

 fibrils arranged spirally. The fibrils 

 are the smallest units that become 

 evident through any simple mechanical 

 disintegration, but by careful chemical 

 treatment they themselves may be 

 subdivided into spindle-shaped fusi- 

 form bodies and the latter into minute 

 spherical units. The spherical unit — 

 Aic ultimate visible component of 

 the cell wall — is about one hundred- 

 thousandth of an inch in diameter, and 

 beyond it the microscope cannot pene- 

 trate. It is possible, however, by indi- 

 rect methods using the ultracentrifuge 



and the X-ray, to determine the 

 approximate size and arrangement of 

 submicroscopic units. 



To the chemist, wood is a storehouse 

 of raw materials only partially devel- 



Top, Cross section of wood, magnified ; cen- 

 ter, cellulose fibers of wood, with lignin re- 

 moved; bottom, lignin structure of 

 wood, cellulose removed. 



M-2968, M-2960. M-9401-F 



