WHITE OAK 569 



Actions and Uses. — Pyrogallol is an excellent agent for 

 the treatment of chronic psoriasis and for ringworm. An 

 ointment containing an amount of pyrogallol, varying from 

 gr.x. to 3 i. to the ounce of lard, is commonly employed. 

 Toxic symptoms may follow its extensive application. 



QuERCUS Alba. White Oak. (U. S. P.) 



Synonym. — Quercus cortex, B.P.; cortex quercus, ecorce 

 de chene, Fr.; eichenrinde, G. 



The bark of Quercus alba Linne (nat. ord. Cupuliferse). 



Habitat. — North America, in woods. 



Description. — In nearly flat pieces, deprived of the corky 

 layer, about 5 Mm. thick; pale brown ; inner surface with 

 short, sharp longitudinal ridges; tough ; of a course, fibrous 

 fracture ; a faint, tan-like odor, and a strongly astringent 

 taste. As met with in the shops, it is usually in irregularly 

 coarse, fibrous powder, which does not tinge the saliva 

 yellow. 



Constituents. — 1, quercitannic acid, 6 to 11 per cent ; 2, a 

 bitter principle, quercin ; 3, resin ; 4, a sugar, quercite. 



Dose.— H., 3 ss.-i. (15.-30.); C, 3 i.-ii. (30.-60.); Sh. & Sw., 

 3i.-ii. (4.-8.); D., gr.x.-xxx. (.6-2.). 



Action and Uses. — White oak bark is identical in action 

 with tannic acid, but the latter is preferable for internal use. 

 Oak bark is a cheap substitute for tannic acid applied 

 externally in poultices, infusions, and decoctions, as an 

 astringent. It is administered internally in infusion, or 

 decoction (1-8), in diarrhoea and dysentery. The infusion 

 may be given in gruel and combined with giuger, opium 

 and alcohol in the treatment of " scouring " in foals and 

 <jalves. 



Catechu. Catechu. (U. S. & B. P.) 



Synonym. — Catechu nigrum, terra japonica, cutch, E.; 

 cachou, Fr.; katechu, pegucatechu, G. 



