432 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



The hairs from immature seeds are known as " dead cotton " 

 and are distinguished by having very thin walls, a thin outer layer 

 of cutin, but lack the essential properties for technical uses. 



GOSSYPII CORTEX. Gossypii Radicis Cortex, Cotton Root Bark. 

 The dried bark of the root of Gossypium herbaceum and of other 

 species of Gossypium (Fam. Malvaceae), biennial or triennial herbs or 

 shrubs indigenous to sub-tropical Asia and Africa, and now cultivated 

 in all tropical and sub-tropical countries. 



Description. In flexible, transversely curved or slightly quilled 

 pieces, 6 to 30 cm. in length, 5 to 15 mm. in diameter, bark 0.2 to 1 

 mm. in thickness; outer surface light brown, longitudinally wrinkled, 

 with small lenticels, periderm frequently exfoliated; inner surface 

 light brown, longitudinally striate; fracture tough, fibrous, surface 

 light brown, tangentially striate, readily separable into fibrous layers ; 

 odor faint; taste slightly astringent and acrid. 



Inner Structure. (Figs. 189 and 190.) Periderm consisting of a 

 number of layers of rectangular or somewhat tabular cells, having 

 thin, yellowish-brown walls; primary cortex consisting of parenchyma 

 containing starch grains, tannin and large secretory cavities filled 

 with a brownish amorphous content; inner bark having nearly closed 

 rings of bast fibers arranged in interrupted concentric circles, sepa- 

 rated radially by medullary rays and tangentially by the leptome tis- 

 sue; bast fibers from 0.300 to 1.000 mm. in length, about 0.015 mm. 

 in width, the walls being about 0.005 mm. in thickness, strongly lig- 

 nified and with very few pores, the ends being acute or markedly 

 attenuate; medullary rays from 1 to 6 cells wide, the cells usually 

 filled with starch, the grains being single or 2- to 4-compound, the 

 individual grains spheroidal and from 0.003 to 0.020 mm. in diameter; 

 calcium oxalate in rosette aggregates, from 0.010 to 0.025 mm. in 

 diameter. 



Powder. Light brown; bast fibers long, narrow, thick-walled, 

 lignified; starch grains somewhat spheroidal from 0.003 to 0.020 

 mm. in diameter, single or compound; parenchymatous cells with 

 irregular yellowish and reddish tannin masses; calcium oxalate 

 crystals in rosette aggregates from 0.010 to 0.025 mm. in 

 diameter. 



Constituents. About 8 per cent of a peculiar, colorless acid 

 resin, which is soluble in water and becomes reddish and insoluble on 

 exposure to air. The drug also contains fixed oil; tannin; starch 

 and calcium oxalate. 



THE FLOWERS of the cotton plant contain an interesting glucoside, 

 gossypetin, which becomes green on oxidation and is colored orange- 



