452 



BOTANY AND PHARMACOGNOSY. 



Constituents.- — Resin 8 to 12 per cent., 85 to 90 per cent, of 

 which consists of a glucoside jalapurgin (convolvulin), which is 



Fro. 195. Transverse section of jalap: Ph, cork cells; Se, resin cells; O, rosette 

 aggregates of calcium oxalate; Si, sieve cells; G, tracheae; C^, primary cambitmi; C^» 

 secondary cambium. — After Meyer. 



insoluble in ether and the more active constituent; and jalapin, 

 which is soluble in ether and resembles scammonin. Jalap also 

 contains calcium oxalate, starch, gum and sugar. 



