Chemical Observations and Experiments on Tohacco. 369 



Art. XIV. — Chemical Observations and Experiments on Tobacco ; 

 by C. C. CoNWELL, M. D. 



The 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 Vauquelin, who 

 makes mention of only a few principles, one of which, viz. starch, I 

 do not find in that plant. 



The following principles, complex and multiplied as they are, all 

 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. 



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. 



8. A large quantity of light yellowish resin. 



9. Nicotin. 



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. 



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, Avhen obtained in a solid form, possesses a bright red 



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