§ 156. ABSINTHIIN, ETC. 147 



(the same), ehimaphilin,^ chiralin^ and ophelic acid, eicutin,^ 

 colvmbin.* 



Cotdin^ crystallizes in quadratic prisms, is sparingly soluble in 

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

 1 30°. IFerric chloride colours the alcoholic solution dark brown. 

 Warming with nitric acid colours cotoln blood-red, pwracotain 

 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. 



Elakrin^ is sparingly soluble in ether, and is coloured yeUow 

 by cone, sulphuric acid. 1 to 2 drops of carbolic acid produce 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, ei'ythrocentawrin,'' eupatorin,^ gvmm,^ 

 hap-hiUery^ (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 

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

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

 boUing 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 pfetroleum 



^ Compare Fairbank, Vierteljahresschr. f. prakt. Fharm. ix. 582, 1860 

 (Amer. Joum. Pharm. xxxii. 256). 



' Compare Kemp, Pharm. Joum. and Trans. [3], 1, 251, 1870 ; Hohn, 

 Archiv d. Pharm. olxxxix. 229, 1869. 



' Compare Wikszemski, ' Ein Beitr. z. Kenntniss der giftigen Wirlcung d. 

 Wassersohierling.' Diss. Dorpat, 1875, and Jahresb. f. Fharm. 493, 1875. 



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

 Joum. Pharm. xx. 3.24). 



* Compare Hesse, und Jobat. Neues Eepert. f. Fharm. xxv, 23, 1876 ; Ber. 

 d. d. CJiem. Geg. x. 149, 1877 ; Annal. d. Chem. und Fharm. cxcix. 17, 1879 

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



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

 N. Jahrb. f. Fharm. xi. 21, 178, 1859 ; Kohler, N. Eepert. f. Fharm. xviii. 

 577, 1869. 



' Compare M^hu, Jahresb. f. Fharm. 70, 1866 ; 92, 1870 ; 56, 1871 (Amer. 

 Journ. Fharm. xxxviii. 303). 



8 Compare Eighini, Joum. f. Fharm. xiv. 623. 



' Compare Pettenkofer, Eepert. f. Pharm. kxxvi. 311 ; Faur^ Jahrb, f. 

 Fharm. xxii. 291. 



' 1° Compare Lermer, Vierteljahresschr. f. prakt, Pharm. xii, 504, 1863 ; 

 Biasell, Amer. Joum. Fharm. xlix. 582, 1877 ; Griessmayer, Ber. d. d. Chem. 

 Gob. x.\. 292, 1878 (Joum. Chem. Soc. xxxiv. 449) ; Isleib, Archiv d. Fharm. 

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

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



10—2 



