VEGETO- ALKALIES. 971 



derived from volatile animal oil (oil of Dippel), namely odorine, 

 ammoline and animine. 



The investigation of this class of bodies was commenced by 

 Derosne, 6 who in 1803 observed narcotine, and by Sertuerner, 

 who, in 1817, recognised in morphine from opium the first 

 vegetable base. These chemists were followed by others, par- 

 ticularly Robiquet and MM. Pelletierand Caventou, who in cin- 

 chona bark, nux vomica, and other vegetable matters found 

 organic bases, in which the medicinal virtues of the plants 

 resided. The analogy of these bases to metallic oxides and 

 their valuable applications in medicine have rendered the class a 

 favourite study with both chemists and pharmacians. The 

 method generally pursued in the preparation of such of these 

 bases as, like morphine, are insoluble in water, consists in treat- 

 ing the vegetable substance containing the base with a dilute 

 acid which forms a soluble salt with the base. This solution 

 is concentrated by evaporation, and slightly supersaturated with 

 a soluble alkali, ammonia, hydrate of lime, magnesia or carbo- 

 nate of soda, by which the vegetable base is precipitated 

 coloured and in an impure condition. To free it from foreign 

 matters, the base or a salt of it is crystallized from alcohol, or 

 if neither the base nor its salt is not much more soluble in hot 

 than in cold alcohol, and therefore does not crystallize well from 

 that liquid, the salt is rendered white by treatment with animal 

 charcoal and repeated crystallization, and the pure base finally 

 precipitated by means of carbonate of soda. 



The extraction of bases which are soluble in water and vola- 

 tile such as conicine, is more difficult. The leaves, flowers, root, 

 or seeds which contain the volatile base are submitted to distil- 

 lation with a weak solution of caustic alkali. The water which 

 distils over is found to be saturated with the organic base, and 

 generally contains besides a quantity of ammonia resulting 

 from the decomposition of a portion of the former. The dis- 

 tilled water is fully neutralised with dilute sulphuric acid, 

 mixed in a concentrated state with caustic alkali, and the whole 

 digested in a close vessel with ether, which last solvent takes up 

 the liberated vegetable base and the ammonia. The ethereal 

 solution being then distilled by the heat of a waterbath, the 

 ether and ammonia escape, and the vegetable base is left pure 

 in the retort. 



