§ 156. ABSINTHIIN, ETC. 147 



(the same), cliimaioliilin,'^ chiratin" and oplielic acid, cicuim,^ 

 columhin.'^ 



Cotdin^ crystallizes in quadratic prisms, is sparingly soluble in 

 cold water, freely in alcohol, ether and chloroform. It melts at 

 130°. Ferric chloride colours the alcoholic solution dark brown. 

 Warming with nitric acid colours cotoin blood-red, jjaracotdin 

 brown. The latter melts at 152° (uncorrected). A description of 

 leucotin, oxyleucotin and hydrocotoin will be found in the re- 

 searches on cotoin and paracotoin above referred to. 



Elaterin^ is sparingly soluble in ether, and is coloured yellow 

 by cone, sulphuric acid. 1 to 2 drops of carbolic acid jDroduce a 

 red tinge, which changes to crimson on the addition of the same 

 quantity of cone, sulphuric acid. (See also § 55.) 



I may mention further, crythrocentaurin,'^ enpatorin,^ guacin,^ 

 hojJ-bitter.'^^ (To isolate the hop-bitter Isleib exhausts hops with 

 cold water, absorbs the bitter principle with charcoal, extracts it 

 from the same with 90 per cent, alcohol, distils, and, after 

 sejDarating the resin, shakes the resulting liquid with ether. He 

 confirms the statement that hop-bitter is not a glucoside, but, on 

 boiling with dilute acids, combines with a molecule of water 

 yielding sparingly soluble lupuliretin. Part of the hop-resin may 

 be removed from aqueous solution by shaking with petroleum 



^ Compare Fairbank, Viertel jahresschr. f. prakt. Pharm, ix. 582, 1860 

 (Amer. Journ. Pharm, xxxii. 256). 



" Compare Kemp, Pharm. Journ. and Trans. [3], 1, 251, 1870 ; Höhn, 

 Archiv d. Pharm, clxxxix. 229, 1869. 



■^ Compare Wikszeraski, ' Ein Beitr. z. Kenntniss der giftigen Wirkung d. 

 Wasserschierling.' Diss. Dorpat, 1875, and Jahresb. f. Pharm. 493, 1875. 



* Compare Boedecker, Annal. d. Chem. und Pharm. Ixix. 37, 1849 (Amer. 

 Journ. Pharm, xx. 324). 



^ Compare Hesse, und Jobst. Neues Eepert. f. Pharm, xxv. 23, 1876 ; Ber. 

 d. d. Chem. Ges. x. 149, 1877 ; Annal. d. Chem. und Pharm, cxcix. 17, 1879 

 (Pharm. Journ. Trans. [3], vi. 764 ; vii. 495, 1019 ; x. 521, 541). 



® Compare Zwenger, Annal. d. Chem. und Pharm, xliii. 359, 1842 ; Walz, 

 N. Jahrb. f. Pharm, xi. 21, 178, 1859 ; Köhler, K Kepert. f. Pharm, xviii. 

 577, 1869. 



7 Compare M<5hu, Jahresb. f. Pharm. 70, 1866 ; 92, 1870 ; 56, 1871 (Amer. 

 Journ. Pharm, xxxviii. 303). 



^ Compare Righini, Journ. f. Pharm, xiv. 623. 



^ Compare Pettenkofer, Eepert. f. Pharm. Ixxxvi. 311 ; Faurc^, Jahrb. f. 

 Pharm, xxii. 291. 



^" Compare Lermer, Vierteljahresschr. f. prakt. Pharm, xii. 504, 1863 ; 

 Bissell, Amer. Journ. Pharm, xlix. 582, 1877 ; Griessmayer, Ber. d. d. Chem. 

 Ges. xi. 292, 1878 (Journ. Chem. Soc. xxxiv. 449) ; Isleib, Archiv d. Pharm. 

 [3], xvi. 345, 1880 (Journ. Chem. Soc. xl. 101) ; Cech, Zeitschr. f. anal. Chem. 

 XX. 180, 1881 (Journ. Chem. Soc. xl. 946). 



10—2 



