190 ALKALOIDS. 



Supposing, then, both these alkaloids tq have been extracted 

 together. Iby shaking with chlorofoitfl, and to have been rfedis- 

 solved in dilute (2 per cent) acetic acid, the addition of dilute 

 sulphuric acid to such a solution would cause the precipitation of 

 the majority of the jervine as sparingly soluble acid sulphate 

 (Simon's vegetable baryta). According to Bullock this salt 

 requires 427 parts of cold wa.ter for solution, and the precipitate 

 contains 1.5 -5 per cent, of sulphuric acid (H2SO4). The hydro- 

 chloric acid precipitate (6 '65 per cent. HCl) is more soluble; the 

 most advantageous method of all is to precipitate nitrate of jervine 

 (soluble in 1,200 parts of cold, water) by adding nitrate of 

 potassitun, to ■ acetic acid solution. Veratro.idine remains in the 

 filtrate, frotn which it can be extracted by shaking with chloro- 

 form. In a similar manner ^aricw may be separated from other 

 cinchona alkaloids in the form of a sparingly soluble nitrate. 



The behaviour of two alkaloids to hoses will more frequently be 

 fouiid to present differences, of which advantage may be taken. 

 Here two cases kre to be distinguished : viz., either one alkaloid 

 is precipitated, and the other left in solution ; or, both are pre- 

 cipitated, but one is redissolved by an excess of the precipitant; 

 whilst the other is not. As an instance of the first of these two 

 cases, the separation of narcoline from nareeine may be cited ; the 

 former is almost completely precipitated by ammonia, whereas the 

 nareeine remains in solution. Morphine and codeine serve to 

 exemplify the second case, which is of more frequent occurrence; 

 excess of ammonia priecipitates the former tolerably completely, 

 but the codeine remains dissolved in lie filtrate, from which it 

 may be extracted by shaking with benzene. Oh the other hand, 

 an excess of lime-water causes the separation of narcotine, but 

 does not precipitate morphine; But nearly the whole of , the 

 latter alkaloid. is thro'wn down if chloride of ammonium be added 

 to the solution in caustic lime (§ 187). 



This method of precipitation with excess of alkali is, however, 

 unreliable in some cases, in which favourable results . might have 

 been anticipated. Strychnine can be separated from an acid 

 solution very satisfactorily by the addition of excess of ammonia ; 

 brucine under the same conditions reuiains in solution until the 

 greater part of the ammonia has volatilized. But if both alkaloids 

 are present together, part of the brucine will separate with the 

 strvchnirie on the addition of ammonia.'' 



' See my ' Ermittelnng von Giften,' 2nd edition, 259. 



