2 
ON LOBELINA. 
Lobelia, the active principle of Lobelia inflata, by S. Colhoun, 
M. D.,* Professor of Materia Medica in Jefferson Medical 
College." At the period that my former essay was written, 
this paper by Dr. C. was cursorily examined, but the fact that 
his active principle was insoluble in ether, at once caused a 
belief that the principles werejdifferent,and that, that contained 
in my essay was unique. A subsequent and more critical exa- 
mination of Dr. C.'s paper has led to the conclusion that he did 
not succeed in isolating lobelina, but that his principle was an 
impure hydrochlorate of that base, as is evident from the fol- 
lowing extract from his paper, viz : 
"The process by which this active principle was obtained, 
was first by dissolving it in acidulated water ; muriatic acid 
being used for this purpose, the menstruum continued to act 
on the leaves for seven hours ; it was then evaporated, the heat 
separating the superfluous acid. 
" Crystals, on the fluid being sufficiently reduced, were dis- 
covered on the bottom of the vessel : they were mixed with 
some foreign earthy salt, the existence of which was proved 
by burning the substance remaining after the evaporation, in a 
small bottle kept for some hours in a red heat. 
" To avoid the salts thus formed with the acid, alcohol was 
used as the solvent ; the extract remaining after its evaporation 
was beautifully transparent, and had the other properties above 
described. [Alluding to a previous description.] It was this 
extract that was principally used to form salts with the acids." 
From these remarks it is evident, that the substance de- 
scribed as lobelina, was really a mixture of the hydrochlorate 
of that base, with such other matter as alcohol will extract from 
the watery extract of Lobelia inflata. Hence, this principle 
could not have had an alkaline reaction, and there is no men- 
tion made in the paper of its possessing this reaction. It states 
that " lobelia [lobelina] forms salts with the acids," not that 
it neutralizes acids ; and consequently we are led to believe 
♦An acknowledgement was due Dr. Colhoun for omitting a notice of his 
paper in the essay before mentioned. Since the present essay has been 
prepared, we lament to state that his death has occurred. 
