Khaki 

 cotton. 



Mature, 

 immature 

 and over- 

 ripe cells. 



Irregular 

 twisting. 



Hygro- 

 scopic 

 property. 



a central core known as the Endochrome to the presence, extent 

 and colour of which the floss owes its peculiar tint. In all wild 

 cottons, for example, the endochrome gives a deep rusty hue (the 

 khaki or red cotton). So very constant is this peculiarity of the 

 uncultivated cottons that its appearance in the field may be accepted 

 as an almost certain sign of a low-grade plant, or of defective 

 cultivation or unsuited environment. It is in all probability a sign 

 of ' reversion ' to an ancestral and presumably hardier or more pre- 

 potent condition, when, with cultivated cottons, even a tendency 

 toward that colour of staple becomes manifest. (Cf. p. 7.) 



Contraction and Twisting. Thus the thickening endochromatic 

 core imparts to the cell, by transmission, its particular tint and 

 gives to it some of its special tinctorial reactions. To a peculiar 

 colour may often be attributed the merit of a staple, as for example 

 the mit afifi as compared with the abassi of Egypt. So again, 

 mention has been made of the different appearances of mature cotton 

 hairs, taken from pods before and after opening naturally. (Cf. p. 26.) 

 It is necessary to enlarge on these subjects. In the first condition 

 the cotton cells are seen to be flat filaments, in the second they have 

 twisted into a spiral form. 



If carefully examined it will be discovered that the cotton cells 

 are thin along what may be called their central plane and slightly 

 thickened outwards. In time this linear thickening becomes very 

 pronounced, but if over -ripening be allowed to ensue the extra 

 deposition of cellulose may cause a serious depreciation in value, 

 the cells becoming in consequence semi-rod-like bodies, devoid of 

 all elasticity and unsuited for spinning purposes. The normally 

 produced secondary deposits are, however, in no instance uniform 

 throughout the length of the cell. Thin portions are left here and 

 there, and, since drying must take place more readily from these, 

 contraction of the cell-wall at such positions would be but the 

 natural consequence. With contraction exerted from the centre 

 toward the circumference, spiral twisting becomes inevitable, and as 

 this takes place at various parts of the cell simultaneously, irregular 

 spiral twisting must necessarily ensue. It would seem probable 

 however, as pointed out by Monie, that spiral twisting normally 

 commences at the top and works toward the base of the cell a 

 consequence possibly of the earlier exposure of the extremity. 



The hygroscopic property of the cotton cell is one of its most 

 interesting features. When not uniform the twisting is coarse and 



