65. ESTIMATION OF ALKALOIDS. 61 



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

 temperature than that of atropine or hyoscyamine.] (See further 

 in 174.) 



Ernriine. 1 cc. of the potassio-mercuric iodide precipitates 

 0*0189 gram emetine. The precipitate has the composition 



Coniine. 1 cc. indicates 0*0125 gram, coniine provided that the 

 solution contain J to 1 per cent, 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 (C 18 H 16 NI) 2 + HgI 2 ( 174, 180). 



Nicotine. 1 cc. indicates '00405 gram nicotine; the composi- 

 tion of the precipitate is C 10 H 16 N 2 I 2 + HgI 2 . 



Strychnine and Brucine. 1 cc. precipitates 0'0167 gram strych- 

 nine and 0-0197 granf anhydrous brucine (in the latter case 

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

 cipitates have the composition C 21 H 29 N 2 2 HI + HgI 2 , and 

 C 23 H 26 N 2 4 HI + HgI 2 ( 174, 180). 



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

 centration being about 1 to 600, and the solution containing 7 to 10 

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

 four equivalents of colchicine to one of HgI 2 . 



Morphine and Narcotine. 1 cc. corresponds to 0'02 gram crys- 

 tallized morphine 2 and 0'0213 gram narcotine. (See also 174.) 



Veratrine, sabadilline, and sabatrine. 1 cc. indicates, according 

 to Masing, s 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 0-0374 gram 

 sabadilline and 0*03327 gram sabatrine. Correction for every cc. 

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

 ( 174). 



Physostlgmme. 1 cc. precipitates 0*01375 gram physostigmine 

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

 position of the precipitate is assumed to be C 15 H 21 N 3 2 HI + Hgl.,. 

 (See also 174.) 



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

 emetine prepared by Podwissotzki are published. 



2 For the application of potassio-cadmic iodide to the quantitative determina- 

 tion of opium alkaloids see Lepage, Repert. f. Pharm. 1875, 613. 



3 Archiv d. Pharm. ix. 310 (Journ. Chem. Soc. xxxii. 369). 



