Chemical Observations and Experiments on Tobacco. 369 
- Arr. XIV.—Chemical Observations and Experiments on Tobacco ; 
by C. C. Conwett, M. D. 
Tue subsequent paragraphs embrace a brief account of a series of 
analytical investigations, as carefully conducted as they were difficult 
in execution, on an article, the commercial and medical importance of 
which, as well as its almost universal consumption as a luxury, is too 
generally appreciated to require comment. It may be readily infer- 
red, that a knowledge of its constituent principles cannot fail to be de- 
sirable. No complete analysis of tobacco, so far as I have read, has 
ever appeared before the public, excepting that of Wauquelin, who 
makes mention of only a few principles, one of which, viz. starch, ¥ 
do not find in that plant. . 
The following principles, complex and multiplied as they are, alt 
enter into the tissue of the Tobacco leaf. 
1. Gum. 
2. Mucus, or a substance soluble in water, as well as in spirit, and 
precipitable from either menstruum by subacetate of lead. 
3. Tannin. 
4, Gallic acid. 
5. Chlorophyllin. xy reticl 
6. A green pulverulent matter, soluble in boiling water, and sub+ 
siding on refrigeration. : 
7. A yellow oil, evolving in a concentrated degree the peculiar 
odor, and possessing the taste of Tobacco; it is the poisonous prin- 
ciple of the leaf. as Beessii 
8. A large quantity of light yellowish resin. 
9. Nicotin. be 
When Tobacco leaves are treated, according to the popular for- 
mula for the developement of Piperin, traces of a crystalline struc- 
ture may be observed; it is this substance alone, which, according to 
the received technology of English chemistry, should be called Ni- 
cotin. cia 
10. Tobacco, treated like opium in Sertuerner’s process for ob- 
taining morphia, yields a white substance, soluble in hot} but nearly 
insoluble in cold alcohol : whether this substance be strictly analo- 
gous to morphia, I am not immediately prepared to assert. 
11. A fine orange red coloring matter, soluble in the acids alone : 
this substance, when obtained in a solid form, possesses a bright red 
Vou. XVII.—No. 2. 20 
