ire ALoiNs. 



sulphuric acid and sugar) ; cnicin} (is said to dissolve green in cone, 

 hydrochloric, red in sulphuric acid. It can be extracted by shaking 

 with benzene (§55), but. is partially precipitated from aqueous 

 solution by basic acetate of lead) ; geraniin,^ laclucin and its allies,* 

 Knin,* Iwpinin^ itnuAafrin,^ olml^qmrdn^ (very sQightly soluble in 

 absolute alcohol) ; sparaifo^ermiw.® 



§ 169. Aloins. — ^There is another group of non-glucosidal bitter 

 principles to which I should like to direct attention ; visf., that of 

 . the aloins— a, series of closely allied but not identical chemical in- 

 dividua. All the members of the group are soluble in. water and 

 alcohol', sparingly only in, ether; but it must be dbseryed that the 

 separate aloins show notable diflferenoes in th^ir beha,viour to water. 

 That obtained from Natal aloes is the most difficultly soluble, 

 whilst the aloin of Cape aloes, which . is possibly isomeric with 

 liataloin, is comparatively freely dissolved.^* 



All the aloins can be obtained in yellow crystals, but show a 

 gi-eat disposition to form supersaturated aqueous solutions in 

 which, perhaj)s, they exist in an amorphous state and free from 

 water of crystallization. From such solutions the aloin can be 



' See Natirelle, Jonm. de Chim. m^d xxi. 69, and Scribe, Comptea reiidus, 

 XV. 802. See also my artiqle on the det ition of foreign bitters in beer in the 

 Archiv.d. Ph^rm. [3], iv. 293, 1874; also Kubioki, 'Beitr. ziv Ermittel. 

 freindet Bitterstoffe im Biere,' Diss. Dorpat, 1874 (Phann. Joum. and Trans. 

 [8], V. 566, 1875), and JundziU, 'tTeber die Ermittel. einiger Bitterstoffe im 

 Biere,' Diss. Dorpat, 1873. 



5 See Miiller, Arohiv d. Pharm. [1], xxii. 29, 1828. 



'Compare Ludwig and Kromayer, Arohiv i. Pharm. cxi. 1, 1862; also 

 Kromayer, ' Bitterstoffe.' 



* See Schroeder, N. Kepert, f. Pharm. x, 11, 1861. 



^ Compare Landerer, ibid.'i. 446, 1854.. This lupinin must not be eon- 

 founded with the glucoside of the sajne name discovered by Schuize and 

 Barbieri in 1878. Compare Ber. d. d. chem. Ges* xi. 2200 (Jbum. Chem. Soc. 

 xxxvi. 467). 



^ Compare Duncan, Phil. Mag. x. 465. 



' Compare Felletier, Annal. de Chim. et dePhysi ne,'iii, 1Q5 ; and Sobrero, 

 N. Jahrb, f. Pharm, iiL 286, 185S. 



' See Gerber, Archiv d. Pharm. xxxiv.167, 1831. 



^ See Peckolt, ■ Zeit-schr. d. allgemeinen oester. Apoth.^Ver. 133, 1878 

 {Pharm. Jouru." and Trans. [3], ix. 162, 1878). 



10 According to Treumann's researches (' Beitr. z, Kenntniss der Aloe,* Diss, 

 Dorpat, 1880) the following are the formulse of the various aloins (containing 

 water of crystallization) csQcnlated to the same number of atoms of oxygen, 

 Barbadces aloin = C48H58O21,, eHjO; Gape aloin ^OjoHsjOjo, eHjO ; Socotra 

 aloin ^O^eHaaOjo, eHjO; Natal aloin ^CisHjjOjo; Zanzibar aloin ^CjsHj^ao, 

 6-7H3O; Curasao aloin=044H5i,05i,, 6H2O. See also Fluckiger, Schweia,' 

 Wochenschr. f. Pharm..331, 1870; Pharm. Jonm. and Trans. [3], Ji. 198, 1871. 



