CRUDE DRUGS. 527 



Constituents. — A bitter, somewhat resinous principle, vibur- 

 nin; valerianic (viburnic) acid and other organic acids; resin; 

 tannin ; calcium oxalate ; ash about 10 per cent. 



Adulterants. — The barks of one or more allied species (espe- 

 cially Viburnum dentatuin, Fig. 179, D), are said sometimes to 

 be substituted for the official bark. 



HAMAMELIDIS CORTEX.— WITCHHAZEL BARK.— 

 The bark and twigs of Hamamelis virginiana (Earn. Hamameli- 

 daCeae), a shrub (Eig. 264) indigenous to Canada and the United 

 States west to Minnesota and south to Texas (p. 286). 



Description. — Bark in transversely curved pieces 5 to 20 

 cm. long, 5 to 15 mm. in diameter, bark .0.5 to i mm. thick; usu- 

 ally with the grayish-brown or reddish-brown periderm removed, 

 outer surface light brownish-red, smooth; inner surface light 

 reddish-brown, longitudinally striate ; fracture short-fibrous ; odor 

 slight ; taste astringent. 



Twigs 2 to 5 mm. in diameter; the outer surface varying in 

 color from, yellowish-brown to blackish-brown, smooth or some- 

 what scurfy, longitudinally wrinkled, and with numerous small 

 lenticels; small twigs somewhat' zigzag from numerous leaf-scars; 

 bark thin, easily separable from the whitish, hard, radiate wood; 

 pith small. 



Constituents. — Gallotannic acid, a glucosidal tannin, and 

 gallic acid. The bark apparently also contains a volatile oil which 

 is obtained by distillation in the preparation of hamamelis water 

 or extract of witchhazel. 



GOSSYPII CORTEX.— COTTON ROOT BARK.— The 

 dried bark of the root of Gossypium herhaceuui, and of other spe- 

 cies of Gossypium (Earn. Malvaceae), biennial or triennial shrubs 

 (Eig. 166) indigenous to sub-tropical Asia and Africa, and now 

 cultivated in all tropical and sub-tropical countries (p. 329). 



Description. — In flexible, transversely curved, or slightly 

 quilled pieces, 6 to 30 cm. long, 5 to 15 mm. in diameter, bark 

 0.2 to I mm. thick ; outer surface light brown, longitudinally wrin- 

 kled, 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. 



