CRUDE DRUGS. 477 



from Rheum rhaponticmn; they are more or less cylindrical, dis- 

 tinctly radiate, and contain, besides chrysophanic acid, rhapontin. 

 Rheum palmatmn, which is cultivated in France, Germany and 

 Russia, produces rhizomes that are lighter in color and less val- 

 uable than the Chinese rhubarb, the constituents being similar to 

 those of Austrian rhubarb. 



The rhizomes of other plants of the Polygonacese have been 

 used as substitutes for rhubarb, as follows : Calligonnm songari- 

 citm of Soongaria; Rumc.v aciitus of Europe; R. obtusifolins of 

 Europe and Asia ; R. abyssiniciis of Abyssinia ; and Polygonum 

 cuspidatum of China and Japan. 



ACONITUM.— ACONITE.— The tuberous root of Aconitum 

 napellus (Fam. Ranunculaceae), a perennial herb (Figs. 84, 141), 

 growing in the mountainous districts of Europe, Asia and West- 

 ern 'North America. It is also cultivated in temperate regions 

 (p. 268). The commercial supplies are obtained from England 

 and Germany, and in England the root is collected in autumn 

 from cultivated plants after the overground parts have died down, 

 whereas in Germany the roots are collected from wild plants dur- 

 ing the flowering period, this being done to distinguish the partic- 

 ular species yielding the drug. The root should be carefully dried. 



Description. — More or less conical or fusiform, 4 to 10 cm. 

 long, 5 to 20 mm. in diameter ; externally dark brown, smooth or 

 somewhat wrinkled, the upper portion with a bud, remains of 

 bud-scales or stem-scars, with numerous root-scars or short roots ; 

 fracture horny, somewhat mealy ; internally, bark light or dark 

 brown, i to 2 mm. thick, cambium irregular, 5- to 7-angled, wood 

 yellowish, in small bundles at the angles, pith light brown, about 

 2 to 6 mm. in diameter; odor very slight; taste sweetish, acrid, 

 pungent, accompanied by a sensation of numbness and tingling. 



The shrunken, hollow, older tubers, together with the over- 

 ground stem-remnants, should be rejected. 



Inner Structure. — See Figs. 206, 309. 



Constituents. — A number of alkaloids have been isolated, of 

 which aconitine is the most important; it occurs to the extent 

 of about 0.75 per cent., and forms rhombic prisms, which are not 

 colored by concentrated sulphuric or nitric acid. An aqueous 

 solution of the alkaloid, after acidulating with acetic acid, gives on 



