884 Wisconsin Academy of Sciences, Arts, and Letters. 
Rubiadin occurs as a glueoside in the root of Rubia tine- 
torium. 1 It crystallizes in yellow needles which melt at 290°. 
It is easily soluble in alcohol, ether, and benzene, but insoluble 
in water and carbon disulphide, also in lime water. In solu¬ 
tions of alkalies it dissolves with a red color. 
Chrysophanic acid, — Dihydroxy-1', 4'-methyl- 1 -anthraquin- 
one (?). 
i. ii. 
Chrysophanic acid occurs in the root of Rheum officinale, 1 
Rheum rhaponticum, 2 Rumex obtusifolius, 3 4 Rumex ecklonianus, 3 
Cassia angustifolia, 5 * Cassia speciosa 1 Rhamnus purshiana, 7 
Rhamnus japonica, G Rhamnus frangulafi and Tecoma ochraceae 8 
Chrysophanic acid crystallizes in yellow leaflets and melts 
at 196°. It is insoluble in water, soluble in alcohol, ether, 
acetone, benzene, chloroform, and petroleum ether. These so- 
1 Jr. Chem. Soc., 63, p. 969, 1137; 65, p. 182; Chem. News, 67, p. 299. 
1 Ann., 309, p. 32; Arch. d. Pharm., 245, p. 680; Ann., 9, p. 85; 50, p. 196; 
107, p. 324. 
2 Berl. Jahres., 23, p. 252; Jahresb. f. Pharm., 1882, p. 262. 
3 Jr. Chem. Soc., 97. p. 1. 
4 Arch. Pharm., 184, p. 37. 
6 Chem. Centralbl., 1864, p. 622; Jr. Pharm. Chirm, 12, p. 505. 
* Apoth. Ztgr., 15, p. 537; 16, p. 257, 538; 17, p. 372. 
7 Proc. A. Ph. A., 52, p. 288. 
* Z. oestei'. Apoth. Ver., 12, p. 31. 
