irO GLUCOSIDES OTHEll THAX TANNINS. 



a green colour and subsequently yield a yellow precipitate. 

 Fraxin is thrown down by acetate of lead.^ 



Syrinf/m (§ 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, sulphuric acid dissolves it with 

 deej) blue colouration ; Fröhde's reagent, blood- red passing to 

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

 from aqueous solution.- 



For fjlobularlti see Walz ;^ for coriamyrtin compare §155; for 

 inttosporln see v. Müller ;^ for samaderin see de Vrij.^ 



Colocynfhin can be obtained in yellowish crystals which dissolve 

 in cone. 'sulphuric acid with the gradual production of a fine red 

 coloiu' ; Fröhde's reagent 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. 



Bryoninis also precipitated by the latter reagent.^' 



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

 cone, sidphuric acid, see Hlasiwetz.''' 



Ainln crystallizes in shining silky needles soluble in hot water- 

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

 Ferrous sulphate colours the aqueous solution hlood-rcd. Both alcoholic 

 and cKßieous solutions gelatinize on cooling. In dilute alkalies apiin 

 dissolves with yellow colouration. 



For datiscln, Avhich is also coloured yellow by alkalies, see 

 Braconnot^ and Stenhouse.-' Ferric cldoride precijiitates it green ; 



^ For ;i numljer of other glncosides and allied substances (argynescin,. 

 aplirodfescin, etc.) discovered by Kochleder in horse-chestnuts, see Joiirn. f. 

 pract. Chem. Ixxxvii. 26, 1863 (Amer. Journ. Pharm, xxxv. 290). 



- I'or the nearly allied ligustrin, see Kromayer, Archiv d. Phai-m. cv. 9». 

 1861 ; for syringopicrin (easily soluble in water), ibid. cix. 26, 1862. 



■> N. Jahrb. f. Pharm, vii. 1, 18.57; xiii. 281, 1860. 



•"The Organic Constituents of Plants,' Melbourne, 1878. 



•■> Chem. Centralblatt, 92, 1859 ; Jahresb. f. Pharm. 208, 1872. See Blume, 

 Amer. Journ. Pharm, xxxi. o42. 



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



' Chem. Centralblatt, 449, 470, 1855. 



'^ Annalcs de Chimic ct de Physique [2], iii. 277, 1816. 



" Annal. d. Chem. und I'harm. xcviii. 166, 1856 (.lourn. Chem. Soc. ix. 

 226). For helianthic acid comi)are Ludwig und Kromayer, Archi\ d. Pharm. 

 [2], .\cix. 1, 1818 (Amer. Journ. Pharni. xxxii. 135). 



