§ 65. ESTIMATION OF ALKALOIDS. 61 



the hyoscine of Hohn and others. Its gold salt melts at a higher 

 temperature than, that of atropine or hyoscyamincj (See further 

 in§ 174.) 



Emetine. — 1 co. of the potassio-mercuric iodide precipitates 

 0-0189 giam emetine. The precipitate has the compositiou 

 C^oHj^NAI^ + Hgl,.! 



Conitne. — 1 cc. indicates 0-0125 gram, coniine provided that the 

 solution contain ^ to 1 per can t* of the alkaloid, as little free acid as 

 possible, and, in addition, 3 to 4 per cent, of chloride of potassium. 

 If these conditions are complied with the composition of the pre- 

 cipitate will be (CigHigNIjjH- Hglj (§§ 174, 180). 



Nicotine. — 1 cc. indicates. 0'0040& gram nicotine; the composi- 

 tion of the precipitate is CijHmNJ^ + Hgl2. 



Strychnine and Brucina. — 1 cc- precipitates 0'0167 gram, strych- 

 nine and 0'0197 gram anhydrous brucine (in the latter case 

 as little free acid as possible should be present). The pre- 

 cipitates have the composition CjiBjaNoO^HI + Hglj, and 

 C23HjeNAHI + HgI,(§§ 174, 180). 



Colchicine. — 1 cc precipitates 0'0317 gram colchicine, the con- 

 centration being about 1 to 600, and the solution containing 7 to 1 

 per cent, of sulphuric acid. The precipitate appears to contain 

 four equivalents of colchicine to one of Hgl^. 



Morphine and Narcotirm. — 1 ec. corresponds to 0'02 gi-am crys- 

 tallized morphine- and 0-6213 gram narcotine. (See also § 174.) 



Veratiine, sdbadilline, and sabalrine. — 1 cc. indicates, according 

 to Masing,^ 0'0296 gram veratrine. Little sulphuric acid only 

 should be present and a correction of 0-000068 gram veratrine 

 made for every cc. of liquid. According to the same chemist, 

 1 cc. of the potassio-mercuric iodide is equivalent to 00374 gram 

 sabadillineand 0-03327 gram sabatrine. CoiTCction for every cc. 

 0-00005 gram of the former and 0000408 gram, of the latter 



(§ 174). 



■Physostigmim. — 1 cc. precipitates 0-01375 gram physostigmme 

 (Masing), Correction for every cc. 0-000105 gram. The com- 

 position of the precipitate is assumed to be CijHjjjSTgOjHI + Hgl^. 

 (See also § 17,4.) 



> This formula, also, will have to be altered as soon as analyses of the pure 

 emetine prepared by Podwissotzki are published. 



2 ForUle application of potassio-cadmic iodide to the qu.intitative determina- 

 tion of opium alkaloids see Lepage, Bepert. f. Pharm. 1875, 618.' 



* Arohiy d. Pharm. ix. 810 (Journ. Chem. Soc. xxxii. 369). 



