170 GLUCOSTDES OTHER THAN TANNINS. 



a green colour and subsequently . yield a yellow precipitate. 

 Fraxin is thrown down by acetate of lead.^ 



Syringin (§ 55) crystallizes in colourless needles, dissolves with 

 difficulty in cold water, more easily in hot water and alcohol, but 

 is insoluble in ether. Basic acetate of lead does not precipitate it 

 from aqueous solution. Cone, sulphuiio acid dissolves it with 

 deep blue colouration ; Frohde's reagent, blood-red passing to 

 violet ; cone, nitric acid, deep red. Chloroform extracts syringin 

 fi'om aqueous solution.*^ 



For globidarin see Walzj'for cm-iamyrtw, compare g 1.55; for 

 pitosporin see V. Miiller ;* for sarMderin see de Vrij.* 



Colocynthin can be obtained in yellowish crystals which dissolve 

 iii cone, sulphuric acid with the gradual production of a fine red 

 colour ; Frohde's leagent produces a cherry-red. It is extremely 

 bitter, easily soluble in water and alcohol, but insoluble in ether. 

 Benzene (§ 55), or better, chloroform or amylic alcohol, extracts it 

 from aqueous solution ; it is precipitated by basic acetate of lead 

 and by tannin. 



Bryonm is also precipitated by the latter reagent.* 



For ononin, which gradually assumes a cherry-red colour with 

 cone, sulphuric acid, see Hlasiwetz.' 



Apiin. crystallizes m shining, silky needles soluble in hot water 

 or, more easily, in hot alcohol. Ether does not dissolve it. 

 Ferrous sulphate colours the aqueous solution blood-red. Both alcoholia 

 dnd aqueous sdwtions gelatinize on eoolmg. In dilute alkalies apiin 

 dissolves with yellow colburation. 



For datiscin, which is also coloui'ed yellow by alkalies, see 

 Braconnot' and Stenhouse.® Ferric chloride precipitates it green ; 



' !FoT a, nnmbev of other gincoeides and allied substances (argyraescin, 

 aphrodseBoin, etc.) discovered by Rochleder in horse-obestnuts, see Joum. f. 

 pract. Chem. lxxxvii,.26, 1863 (Amer. Joum. Phatm. xxxy. 290). 



^ For the nearly allied ligustrin, see Kromayer, Arehiv d. PhaTm. cy. 9r 

 1861 ; for Byringopicritt ^easily soluble in. water), ibid. cix. 26, 1882. 



3 N. Jahrb. f. Pharm. yii. 1, 1857 ; xiii. 281, 1860. 



* ' The Organic CoiiBtituents of Plants,' Melbourne, 187S. 



» Chem. GentralWatt, 92, 1859 ; Jahresb. f. Pharm. 208, 1872. See Blume, 

 Amer. Joum. Phatm. xxxi, 342. 



« N. Jahrb, f. Pharm. ix. 65, 217, 1859 (Amer. Journ. Pharm. xxxi. 249). 



' Chem. Centralblatt,.449, 470, 1855. 



« Annales de Chimie et de Physique [2], iii. 277, 1816, 



'.Annal. d. Chem. und Pharm, xcviii. 166, 1856 (Journ. Chem. Soc. ix. 

 226). For helJanthic acid compare Ludwig und Kromayer, Archir d. Pharm. 

 [2], xcix. 1, 1848 (Amer. Joum. Pharm. xxxii. 135). 



