§ 148. BHINACANTHIN, ALKANNIN, ETC. 135 



into sagas and alizarin. ' According to Stenhouse, morindin 1,9 

 identical with ruberythric acid, morindon with alizarin (which is 

 doubted by Stein), and munjestin with pnrpurin. 



With regard to the constituents of maddei" that have been here 

 mentioned, and some others that accompajiy or can be obtained 

 from them, I refer in particular to the investigations of Schunk, 

 Bbchleder, Stenhouse and others, for an account of which 

 Gmelin's ' Chemistry ' may be consulted. 



Tor rhamnin, axmthorhamnin, chrysorJuimnin, and their allies, see 

 Fleury and Biswanger,' Qrtlieb, Liebeniiann, and Hermann.^ 



lihinacanihin, discovered by Liborius in Rhinacanthus com- 

 mimis, appears to possess some of the properties common to 

 anthraquinone-derivatives.* Ifc occurs in- the intercellular spaces 

 in the root bark, is soluble in ether, alcohol and dilute alkali, but 

 insoluble in pure and acidulated water. Alkalies produce a deep red 

 colouration, which is discharged or changed to greenish by acids. 



Alkmmin is insoluble in water, but yields fine red solutions 

 with ether, alcohol, bisulphide of carbon, fixed and ethereal oils. 

 The spectrum is figured on Plate I., 11. Alkannin is uncrys- 

 tallizable, dissolves in concentrated sulphuric acid (violet), in 

 alkalies (blue), and in alcoholic ammonia. 



Bixin behaves similarly to water, alcohol and ether. It dissolves 

 in aqueous alkalies also (blit the compounds thus produced are 

 sparingly soluble in alcohol), and is coloured blue by conceiitrated 

 iiulphuiie acid.*. 



Curcumm^ is also insoluble in water, but is dissolved yellow by 

 ether and alcohol, brown by alkalies. Boracic acid colours it red, 

 changing to dark blue on the addition of an alkalL (For its spec- 

 trum see Plate I., 12.) 



For camhogic acid, which is dissolved yellow by concentrated 

 sulphuric acid, see Johnstone* and Buchner.' 



' Journ. de Phann. et de Chim, xxvii. 666 ; Eepert. f. Pbarm. civ. 64. 



^ Bull, de la' Soc. de Mulhouse, xxx. 16 ; Ber. d. d. chem. Ges. xi. 16i8. 

 See also Lefort und Stein, Jahreeb. f. Phann. 145, 1867 ; 127, 1868 ; 123, 

 1869 (Jonrh. Chem. Soc. xxxvi.). 



3 Site Ber. d. Dorpater Naturf. Ges. 277, 1879 (Pharm. Journ. and Trans. 

 [3],ix. 162). 



* Compare Stein, Chem. Centralblatt, 939, 1867. 



' See iiinda und Daube, Joum. f. prakt. Chem. ciii. 474, and New Series, 

 ii. 86. 1870 (Journ. Chem. Soc. xxiv. 152). 



« Phil. Mag. 281, 1839. 



' Annal. d. Chem. und Pharm. xIt. 7?, 1843 (Amer. Joum, Pharm. xv. 129). 



