438 CONVOLVULACE^. 



causes the separation of protoxide of copper from an alkaline tartrate of 

 that metal. 



A second bitter principle, Chiratin, C^*'H^^O^^, may be removed by 

 means of tannic acid, with which it forms an insoluble compound. 

 Chiratin is a neutral, not distinctly crystalline, light yellow, hygro- 

 scopic powder, soluble in alcohol, ether and in warm water. By boiling 

 hydrochloric acid, it is decomposed into Chiratogenin, C^^H-^0^, and 

 ophelic acid. Chiratogenin is a brownish, amorphous substance, soluble 

 in alcohol but not in water, nor yielding a tannic compound. No 

 sugar is formed in this decomposition. 



These results exhibit no analogy to those obtained in the analysis 

 of the European gentians. Finally, Hohn remarked in chiretta a 

 crystallizable, tasteless, yellow substance, but its quantity was so 

 minute that no investigation of it could be made. 



The leaves of chiretta, dried at 100° C, afforded 7"5 per cent, of ash; 

 the stems 3"7 ; salts of potassium and calcium prevailing in both. 



Uses. — Chiretta is a pure bitter tonic, devoid of aroma and astrin- 

 gency. In intense bitterness it exceeds gentian, Erythrcea and other 

 European plants of the same order. It is much valued in India, but is 

 not very extensively used in England, and not at all on the Continent. 

 It is said to be employed when cheap, in place of gentian, to impart 

 flavour to the compositions now sold as Cattle Foods. 



Substitutes and Adulteration — Some other species of Ophelia, 

 namely, 0. angustifolia Don, 0. densifolia Griseb., 0. elegans Wight, 

 0. pulchella Don, and 0. multijiora Dalz, two or three species of 

 ExacuTYi, besides Andrographi» paniculata Wall., are more or less 

 known in the Indian bazaars by the name of Chiretta^ and possess 

 to a greater or less degree the bitter tonic properties of that drug. 

 Another Gentianacea, Slevogtia orientalis Griseb., is called Chota 

 Chiretta, i.e. small chiretta. It would exceed due limits were we to 

 describe each of these plants : we have therefore given a somewhat 

 detailed description of the true chiretta, which will suffice for its identi- 

 ffcation. We have frequently examined the chiretta found in the 

 English market, but have never met with any other than the legitimate 

 sort.^ Bentley noticed in 1874 the substitution of Ophelia angustofolia, 

 which he found to be by far less bitter than true chiretta. 



CONVOLVULACE^. 



SCAMMONIUM. 



Scammony ; F. Scammonee ; G. Scammoniuvi. 



Botanical Origin — Convolvulus Scammonia L., a twining plant 

 much resembling the common C. arvensis of Europe, but differing 

 from it in being of larger size, and having a stout tap-root. It occurs 



^ Moodeen SheriflF, Siippl. to the Pliarma- ^ Mr. E. A. Webb has pointed out a case 



copaia of Irulia, 1869. pp. 138. 189. — Con- of false-packing in which the roots of 



suit also PAannaco/jcEJa q/'/ndia, 1868. pp. Rubia coriUfolia L. {Munjit) had been en- 



J48-9. closed in the bundles of chiretta. 



