108 
ORIGINAL COMMUNICATIONS. 
to dryness, when the well known and characteristic crystals 
of nitrate of potassa presented themselves. 
Experiment 15. — The exhausted residue of the experi- 
ment fourteen, was treated with nitric acid, which caused 
effervescence, afterwards diluted with water and filtered. 
This solution was precipitated white by the oxalate of ammo- 
nia, and deep blue by the ferro-cyanuret of potassium. 
It may be inferred from the foregoing experiments that 
the principal constituents of the Lobelia Inflata are as follows, 
viz: 
1st. Gum; 2d. Gallic acid; 3d. Volatile oil; 4th. Greenish 
resin or chlorophyle; 5th. A green, fixed, oily, matter; 6th. 
JI peculiar, alkaline, acrid principle; 7th. Salts of lime, and 
potassa; 8th. Oxide of iron; and to these may be added Lig- 
nin. 
From the foregoing observations, it will be seen that a 
marked analogy may be traced between Lobelina and Nico- 
tina, the active principle of the Nicotiana tabacum. Its 
uncrystallizability, its loss of odour by acidifying combinations, 
its acetate being not crystallizable, and lastly the minute pro- 
portion it holds with regard to the plants, bulk for bulk, 
are some amongst other striking marks of their resemblance. 
Judging from a variety of experiments, it can hardly occupy 
more than y J^th, weight for weight, while tobacco, according 
to Berzelius, yields but one part in a thousand. This re- 
mark applies more particularly to the plant as a whole, for the 
seeds contain, at least, twice the quantity. 
The empyreumatic oil, as obtained in experiment thirteen, 
is so analogous in some of its sensible properties, to that 
obtained from tobacco, as still farther to warrant the belief of 
a similarity in chemical properties with that plant, though in 
a less concentrated form. Had the heat employed in its 
formation been more moderate and better regulated, there 
can be but little doubt that the product would have had a still 
more striking analogy. 
It is a curious fact, that the agitation of ether with the in- 
