RHUBARB 549 



Rheum. Rhubarb. (U. S. P.) 



Synonym. — Rhei radix, B.P.; rhubarbe, Fr.; rhubar- 

 ber, G. 



The root of Rheum officinale Baillon (nat. ord. Poly- 

 gouacese). 



Description. — In cylindrical, conical or flattish segments, 

 deprived of the dark brown, corky layer, smoothish or some- 

 what wrinkled ; externally covered with a bright yellowish- 

 brown powder, marked with white, elongated meshes, con- 

 taining a white, rather spongy tissue and a number of sh6rt, 

 reddish-brown or brownish-yellow strige ; compact, hard; 

 fracture uneven ; internally white, with numerous red, 

 irregularly-curved and interrupted medullary rays, which are 

 radially parallel only near the cambium line ; odor some- 

 what peculiar, aromatic ; taste bitter, somewhat astringent. 

 When chewed, rhubarb feels gritty between the teeth, and 

 imparts a yellow color to the saliva. 



Constituents. — 1, a glucoside, chrysarobin (C27H30O14), 

 which yields 2-3 per cent, of chrysophanic acid (CigHioOJ, 

 also called rhein or chrysophan ; 2, rheotannic acid (CaeHggOJ, 

 which gives astringency to rhubarb ; 3, calcium oxalate (35 

 per cent.), causing grittiness ; 4, resinous bodies : phseoretin, 

 emodin, aporetin and erythroretin. Chrysophanic acid and 

 the resins are somewhat purgative, but the exact purgative 

 principle has yet to be discovered. 



Dose.—StomacUc—R. k C, I i.-ii. (30.-60.); Sh., 3 i. (4); 

 D. & Cats, gr.v.-x. (.3-.6). 



3Iild Purgative — Foals and Calves, 3 i.-^ii- (4.-8.); D., 

 3 i.-ii. (4.-8.). 



PREPARATIONS. 



Extractum Rhei Fluidum. Fluid Extract of Rhubarb. 



(U.S. P.) 



Made by maceration and percolation with alcohol and water, and 

 evaporation, so that 1 Cc. = 1 Gm. of the crude drug. 

 Dose. — Same as that of rhubarb. 



