CHAPTER V. 



SCIENCE IN ITS APPLICATION TO TOBACCO. 



Few plants are so susceptible to soil, feeding and 

 culture, as tobacco. Certainly no other crop requires 

 more scientific knowledge to grow it to perfection. 

 Men who have raised it for years, who have closely stud- 

 ied their own and others' experiments, agree with the 

 authors that the scientific aspect of tobacco culture is 

 just beginning to be understood. The curing of the 

 leaf, and its subsequent fermentation, are also only just 

 beginning to be understood. All these matters open up 

 most fascinating fields in chemistry, physics and bacte- 

 riology, upon which we have space to but briefly touch. 



AS TO THE COMPOSITION OF TOBACCO. 



Constituents of Tobacco Leaf. Nicotine is the ac- 

 tive principle of tobacco upon which its peculiar value 

 depends. To it the narcotic and intoxicating qualities of 

 the leaf are mainly due. It is an oily substance that 

 quickly evaporates, and has a strong, pungent and pecul- 

 iar odor. Nicotine is present in the plant from the 

 time it commences to grow in the seed bed, until it has 

 reached maturity and gone through all the fermentative 

 changes incident to curing, sweating and manufacture. 

 The flavor and characteristic odor of tobacco are supposed 

 to be due to a volatile substance called nicotianine. For 

 practical purposes it may be considered with nicotine, 

 or as a part of it. 



The percentage of nicotine varies in the different 

 parts of the plant, and this variation increases as the 

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