CHAPTER XII. 

 DECORTICATION. 



DECORTICATION is the separation of textile fibres from the 

 woody or pulpy matter with which they are generally associated. 

 There are two distinct classes of fibrous plants, i.e., those 

 in which the fibre is found in the stem of the plant, and those 

 in which the fibre forms the structural system of the leaf. 

 To the first class belong flax, true hemp, jute and ramie, 

 and to the latter most of the cordage fibres such as Manilla, 

 New Zealand and Mauritius hemps, Sisal, &c. 



When found in the stem of the plant, the fibres usually sur- 

 round the woody matter, to which they are bound by pectic or 

 gummy matter and are generally covered by a skin of varnish 

 which it is necessary to remove. 



When the fibre is found in the leaves of the plant it is usually 

 covered up by a succulent pulp which must be removed before 

 the fibre can be seen. 



The separation of stem fibres is much more easily accom- 

 plished than is the separation of leaf fibres. In the former 

 case it is only necessary to dissolve the gummy matter which 

 binds the fibre to the boon or harl and then to break 'up 

 and knock or shake out this woody matter. 



The gummy or pectic matter which binds the fibre to the 

 woody core of the flax, true hemp and jute plants, is dissolved 

 and decomposed by fermentation or retting. In the case of 

 flax and hemp the retting process may be done in two ways ; 

 the quicker method being known as water-retting and the 

 other as dew-retting. Jute is always water-retted. Water- 



