400 LOBELIACE^. 



■ 



trimmed. The cakes arrive wrapped in paper, sealed up and bearing 

 the label of some American druggist or herb-grower. 



Lobelia has a herby smell and, after being chewed, a burning acrid 

 taste resembling that of tobacco. 



Chemical Composition — Lobelia has been examined by Procter, 

 Pereira (1842), Keinsch (1843), Bastick (1851), also by F. F. Mayer.' 

 The first-named chemist^ traced the activity of the plant to an alkaloid 

 which he termed Lohelina, and his observations were confirmed by the 

 independent experiments of Bastick.* Lewis (1878) obtained it by 

 mixing the drug with charcoal and exhausting the powder with water 

 containing a little acetic acid. The liquid is cautiously evaporated to 

 the consistency of an extract and triturated with magnesia, from the 

 excess of which the aqueous solution of lobeline is separated by filtra- 

 tion. It is agitated with amylic alcohol (or ether), which by spontane- 

 ous evaporation affords the alkaloid. The latter is again dissolved in 

 water and filtered through animal charcoal; from the dried powder 

 lobeline is to be removed by ether. 



Lobeline is an oily, yellowish fluid with a strong alkaline reaction, 

 especially when in solution. In the pure state it smells slightly of the 

 plant, but more strongly when mixed with ammonia. Its taste is 

 pungent and tobacco-like, and when taken in minute doses, it exercises 

 in a potent manner the poisonous action of the drug. Lobeline is to 

 some extent volatile, but its decomposition begins when it is heated to 

 100' C. either pure or in presence of dilute acids or caustic alkalis. 

 Lobeline dissolves in water, but more readily in alcohol or ether, the 

 latter of which is capable of removing it from its aqueous solution, 

 neutralizes acids, forming with some of them crystallizable salts, so^ 

 in water or alcohol. 



The herb likewise contains traces of essential oil (the Lohelianin of 

 Pereira ?), resin and gum. The seeds afforded Procter about 30 per 

 f^^'i^^ fixed oil, sp. gr. 0-940, which was found to dry very rapidly Ihe 

 Lohelim of Keinsch appears to be an indefinite compound. 

 ^ In 1871 Enders at our request performed some researches on Lobelia 

 in order to isolate the acrid substance to which the herb owes its taste. 

 He exhausted the drug with spirit of wine and distilled the hquid m 

 presence of charcoal, which then retained the acrid principle. The char- 

 coal was washed with water, and then treated with boiling alcolioj 

 Ihis on evaporation yielded a green extract, which was further purineQ 

 by means of chloroform. Warty tufts were thus finally obtained, ye^ 

 always of a brownish colour. The tufts are readily soluble in ether ana 

 tt^'^t^^?^_^S^ }- --^^^ > they possess the acrid taste o 



It 



luble 



bory 



;oluble 



plumbic salt is insoluble in water. 



, ^ ^, „^^^ica,o ita piuiuuic sail IS msoiUDie lu wav^^^^ i 



Lewis suggests that lobelacrin is nothing else than lohehaUJI 

 tobehne, which he believes to exist ready formed in the plant. From 



