148 EESmS, BIT TEE PRINCIPLES, ETC. 



spirit. Griessmayer has availed himself of this property of hop- 

 resin in the examination of beer. Cf. § 55.) Other bitter prin- 

 ciples are hurin,'^ jervasic acid,' juniperin,^ Uriodendrin,^ hjcopin,^ 

 marruhm,^ mangostln,^ masopin^ and meconin.^ The last-named is 

 soluble in hot water, and can be extracted from'aqueous solution 

 after acidification with sulphuric acid, by shaking with benzene, 

 chloroform, or amylic alcohol. With benzene it can be obtained 

 fairly pure, and can be detected by cone, sulphuric acid, in which 

 it dissolves Avithout at first producing any colouration ; but the 

 solution gradually assumes a greenish, and in the course of twenty- 

 four hours a reddish tinge. If the liquid is then warmed, the colour 

 changes to emerald-green, blue and violet, and becomes finally red. 



Meconin is accompanied in opium by meconic acid, which is 

 sparingly soluble in water and ether, but more easily in alcohol. 

 Boiling with water or dilute acids decomposes meconic acid ; with 

 ferric chloride it strikes a blood-red colour, which is not discharged 

 by a little hydrochloric aci or chloride of gold. It can be 

 removed from aqueous solution by shaking with amylic alcohol. 

 Meconate of calcium is soluble, but the magnesium salt only 

 sparingly so. Chelldonic acid from Chelidonium majus is sparingly 

 soluble both in cold water and in alcohol.^'' 



There may be further mentioned here, mcthysticin^^ (which is 

 slightly soluble in cold ether and dissolves in pure cone, sulphuric 

 acid with fine reddish-violet, in commcrcicd with blood-red coloura- 

 tion), Jcawciin,^" narthecin,^^ nucin'^^ (coloured purple by alkalies), 



^ Compare Boussingault and Rivero, Annal. de Chim. et de Phys. xxviii. 430 

 (Amer. Journ. Pharm, ii. 346). 



^ Compare Weppen, Jahresb. f. Pharm. 31, 1872 (Journ. Chem. Soc. xxvi. 

 906). 



•' Compare Steer, Wiener Acad. Anz. B. xxi. 383. 



•* Compare Emmet, Kepert. f. Pharm. Ixxv. 88 (Amer. Journ. Pharm, iii. 5). 



■'' Compare Geiger, Repert. f. Pharm, xv. 11. 



" Compare Kromayer, Archiv d. Pharm, cviii. 257, 1862. 



7 Compare W. Schmidt, Annal. d. Chem. und Pharm, xciii. 83, 1854 (Amer. 

 Journ. Pharm, xxvii. 331). 



** Compare Genth, Annal. d. Chem. und Pharm, xlvi. 126, 1843. 



■' Compare Pelletier, Annal. d. Chem. und Pharm. Ixxxvi. 190, 1853, and 

 Anderson, xcviii. 44, 1856. See al.so my 'Ermittel, d. Gifte,' 2nd ed., 238. 



1" See Lerch, Chem. Centralblatt, 449, 1846. 



" Compare Nölting and Kopp, Monit. Hcientif. [3], iv. 920, 1874 (Pharm. 

 Journ. Tran.s. [3], vii. 149). 



1- Ibid. 



'» Cmpare Walz, N. Jahrb. f. Pharm, xiv. 345, 1861. 



'^ Compare Vogel and lleinschauer, N. Kepert. f. Pharm, v. 106 (1856) ; 

 vii. 1 (1858). 



