§ 183, SEPARATION BY PRECIPITATION. 193 



For the separation of morphine from narcotine by ether, see 

 § 187. Ether and chloroform (free from alcohol) can also be 

 used to separate the former from- codeine and thebame. Morphine 

 Can be separated from thebaiue, codeine, and narcotine, by the 

 method of agitation ; the last three are removed by benzene 

 from ammoniacal solution, whilst scarcely traces of morphine are 

 dissolved. 



In a similar manner ddphinim and ddphirmdine may be sepa- 

 rated from staphisagrvne by agitation with ether, in which the 

 latter is insoluble ;i after removing the first two, staphisagrine 

 may be' extracted with chloroform. 



§ 183. Use of Suits, etc. ; Separation of Qmnine amd Ginchonidin.e, 

 etc.^ — Instances of the use of salts tin the separation of alkaloids 

 may be found in the employment of tartrates for the quantitative 

 estimation of quinine and cinchonidine in the presence of quiaidine 

 and cinchomne (cf. § 184, I.); by means of iodide of potassium or 

 sodimn, gmnidine can be separated from cinchonine and ' amorpJums 

 alkaloid' (cf. § 184, IV.). Wittstein recommended conversion into 

 oxalates in alcoholic solution for separating s^c^me and brucine;^ 

 quinine may be freed from cinchonidine by precipitation as hera- 

 palMte*(d.^ 184, II.). 



The separation of calabarine from physostigmine by potassio- 

 mercuric iodide, has already been described in § 174; the same 

 method might perhaps be feasible with chdidonme and sanguinarine.^ 



Chloride of gold can be used in separating rmiscarine from 

 amaiMne, as the double- salt of the former is more soluble in 

 water than that of the latter.' 



Perehloride of platinum \tui: the salt used in separating jjo^^^twe 

 from the olJier bark alkaloids, as the double salt of platinimi wiiih 

 that alkaloid is very sparingly soluble in water. By means of the 

 same salt, ammonia may be separated from those alkaloids and 

 amides that yield double salts of greater solubility (§ 98). It 

 must, however, be borne in mind that certain alkaloids undergo 



' See the paper by Marquis and myseK previously quoted. 



° Oomp. !MoenB, loc, cit.j Johanson, Archiv d. Fharm, x. 418. 1877 ; 

 Hielbig, foe. cit. 



' VierteljahresBChrift f. praot. Pharm. viiL 409, 1859. 



^•Compare Herapath, Phann. Joum. and Trans. [1], xi. 448 ; xii. 6 ; de 

 Vrij [3], vi. 461 ; N. Tijdsehr. voor de Pharm. 1881 ; Hielbig, loc. cit. 



^ See my ' Chem. Werthbestimmung,' 102. 



' Compare Hamack, Archiv f. exper. Pathol, und Pharmacol, iv-. 82, 187.5. 



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