191 NICOTIANA TABACUM 



De Candolle, Gcogr. Bot., ii, p. 848; Lindl., Med. Bot., p. 513; 

 Pritzel, Thesaurus Literat. Bot., ed. 1, p. 457. 



Official Part and Names. TABACI FOLIA ; the dried leaves of 

 Virginian Tobacco (B. P.). The dried leaves (Tabaci Folia) (I. 

 P.). TABACUM; the commercial dried leaves (U. S. P.). 



Preparation, Kinds of Tobacco, and Commerce. In America, 

 from which our official tobacco leaves are directed to be obtained, 

 the tobacco harvest takes place in August, when the plants are 

 regarded as ripe. At this period the stems are cut off from the 

 plants just above their roots, and then hung up in the drying 

 houses, where they are exposed to a considerable degree of heat, 

 and during this process of curing, as it is termed, they become 

 moist, or in bther words, are said to sweat. They are then further 

 dried and stripped of their leaves ; and the latter are then tied in 

 bundles, and packed for exportation, &c. In the process of pre- 

 paration tobacco leaves appear to undergo a kind of fermentation 

 by which important chemical changes take place in their composi- 

 tion, one of the most evident being the formation of some new 

 volatile principle, for the heavy narcotic odour of the dried leaves 

 is wanting in the fresh ones. 



In commerce two states of tobacco are distinguished, in one of 

 which it is termed unmanufactured or leaf tobacco, in the other 

 manufactured tobacco. In the British Pharmacopoeia the dried 

 leaves of Virginian tobacco, or unmanufactured tobacco, cultivated 

 in America, are alone official. Under the head of manufactured 

 tobacco are included the different forms of tobacco prepared for 

 chewing and smoking, and for taking as snuff. The description 

 of the numerous forms and varieties of manufactured tobacco does 

 not come within our province. 



Besides Virginian tobacco, which is derived, as we have seen, 

 from Nicotiana Tabacum, the plant now under notice, other com- 

 mercial kinds from the same plant are also obtained from the 

 United States of America, as Maryland, Kentucky, &c. By far 

 the greater proportion of unmanufactured tobacco imported into 

 the United Kingdom is from the United States. Professor 

 Thiselton Dyer has also just proved that Latakia Tobacco, which 



