ALKALOIDS. 



391 



A little water is now added to the residue, and this solution, which should yet 

 have a slight acid reaction, is shaken with about three times its own volume of 

 acetic ether, which dissolves some coloring and extractive matters, but does not 

 act upon the alkaloid salts. The two strata of liquids which form on standing 

 in a tube are separated by means of a pipette, and the operation is repeated, if 

 necessary, i. e., if the ether should have been strongly colored. 



The remaining acid aqueous solution is next slightly supersaturated with 

 sodium carbonate, which liberates the alkaloids. Upon now shaking the solu- 

 tion with acetic ether, all alkaloids are dissolved in this liquid, which, after 

 being separated from the aqueous solution, leaves upon evaporation, at a low 

 temperature, the alkaloids generally in a sufficiently pure state for recognition 

 by special tests. It may, however, be necessary to purify the residue further 

 by neutralizing with an acid, allowing to crystallize in a watch-glass, and sep- 

 arating the small crystals from adhering mother-liquor. 



The above method for detecting alkaloids in the presence of organic matter 

 generally answers the requirements of students. 



The practical toxicologist has in most cases of poisoning some data (deduced 

 from the symptoms before death, or from the results of the post-mortem exam- 

 ination) pointing to a certain poison, which, of course, facilitate his work con- 

 siderably. 



Important alkaloids. 



a. Liquid and volatile alkaloids. 



Sparteine, C 15 H 26 N 2 Scoparius. 



Coniine, C 8 H 17 N Conium maculatum. 



Nicotine, C 10 H U N 2 Tobacco plant. 



b. Solid and fixed alkaloids. 



