176 A LOINS. 



sulphuric acid and sugar) ; cniciii'^ (is said to dissolve green in cone, 

 hydrochloric, red in sulphuric acid. It can he extracted hy shaking 

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

 solution hy basic acetate of lead) ; geraiiiin,- laduciii and its allies,^ 

 linin,^ hiplnia,^ mudarin,^ olivil,'' querem^ ('V'ery slightly soluble in 

 absolute alcohol) ; sparattospermin.^ 



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

 principles to which I should like to direct attention ; -viz., 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 observed that the 

 separate aloins shoAv notable differences in their behaviour to water. 

 That obtained from Natal aloes is the most difficultly soluble, 

 Avhilst the aloin of Cape aloes, Avhich is possil)ly isomeric with 

 natal oin, is comparatively freely dissolved. ^'^ 



All the aloins can be obtained in j'ellow crystals, but show a 

 great disposition to form supersaturated aqueous solutions in 

 which, perhaps, they exist in an amorphous state and free from 

 water of crj-stallization. From such solutions the aloin can be 



^ See Nativelle, Journ. de Chim. med. xxi. 69, and Scribe, Comptes rendns, 

 XV. 802. See also my article on the detection of foreign bitters in beer in the 

 Archiv d. Pharm. [3], iv. 293, 1874; also Kubicki, 'Beitr. zur Ermittel, 

 fremder Bitterstoffe im Biere,' Diss. Dorpat, 1874 (Pharm. Jonrn. and Trans. 

 [3], V. 566, 1875), and Jundzill, 'Ueber die Ermittel, einiger Bitterstoffe im» 

 Biere,' Diss. Dorpat, 1873. 



- See Müller, Archiv d. Pharm. [1], xxii. 29, 1S2S. 



•' Compare Ludwig and Kromayer, Archiv d. Pharm, cxi. 1, 1862 ; als» 

 Kromayer, ' Bitterstoffe.' 



^ See'Schroeder, N. Kepert. f. Pharm, x. 11, 1861. 



•'' Compare Landerer, ibid. i. 446, 1854. This lupinin must not be con- 

 founded with the glucoside of the same name discovered by Schulze and 

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

 xxxvi. 467). 



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



7 Compare Pelletier, Annal. de Chim. et de Physique, iii. 105 ; and Sobrcro, 

 X. Jahrb. f. Phai-m, iii. 286, 1855. 



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



" See Peckolt, Zeitschr. d. allgemeinen oester. Apoth. Ver. 133, 187S 

 (Pharm. Journ. and Trans. [3], ix. 162, 1878). 



1" According to Treumann's researches (' Beitr. z. Kenntniss der Aloe,' Diss, 

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

 water of crystallization) calculated to the same number of atoms of oxygen. 

 Barbadoes aloin = Cj^HjjjO.,,,, 6HoO ; Cape aloin = C4„Hr,„()._,,„ 6HoO ; Rocotra 

 aloin = C4-,H,,<,0„,|, 6H./) ; Natal aloin = C4r,Hr,,;Oo(i ; Zanzibar aloin = Cj^HjoOoq, 

 6— 7H/) ; Curasao aloin = C44H,,„0.jf|, 6H.jO. Sec also Eliickiger, Schweiz. 

 Wochenachr. f. Pharm. 331, 1870 ; Pharm.'journ. and Trans. [3], ii. 193, 1871. 



