94 CORDAGE FIBRES 



Under the microscope it presents the appearance of a flat, 

 ribbon-like band, more or less twisted on its longitudinal axis. 

 The cell walls are rather thin, and the lumen occupies about 

 two-thirds of the entire breadth, and shows up very pro- 

 minently in polarized light. Between its thickened edges the 

 fibre exhibits the appearance of a finely granulated surface. 

 Fibres of dead cotton, or those which have not reached 

 maturity, are seldom spirally twisted, and do not have a lumen, 

 but are thin, transparent bands. Immature and over-ripe 

 cotton fibres exhibit a smooth, straight, flat appearance, and 

 the external walls of the fibre are very thin. 



