22 



THE COTTON PLANT. 



it the power 

 twisted. If 



FIG. 4. aandc, Mag- 

 nified Drawings of 

 Cotton Fibre ; b, the 

 Same, from some 

 Unravelled Threads 

 of Cotton Cloth 

 (Royle). 



the hair give 

 a flat ribbon, 



it possesses of forming a thread when 

 examined under the microscope, the 

 cotton hair will be found ap- 

 parently to consist of two deli- 

 cate, transparent tubes, the one 

 twisted round the other, so as 

 to have the appearance of two 

 pieces of cord wound round 

 each other (Fig. 4). If, how- 

 ever, the hair be examined in 

 its young state, it will be 

 found to be an untwisted, 

 cylindrical tube. It is during 

 its growth that this change 

 takes place. As the seeds and 

 hairs grow, the capsules do not 

 appear to expand with equal 

 rapidity ; and, consequently, 

 the hair is exposed to pressure 

 on all sides. The result of 

 this is, that the hair collapses 

 in the middle, leaving a half- 

 formed tube on each side. 

 These uncollapsed portions of 

 it the ' appearance,' says Bauer, ' of 

 with a hem or border at each edge.' 



