NATURE AND PROPERTIES. 257 



acid, ammonia, and other substances less known are 

 chiefly, if not entirely, derived from the products of the 

 decomposition of albuminoids. The substances that 

 cause the objectionable pungent smell in tobacco are 

 formed from the broken-up constituents of these high 

 combinations. The conditions under which these bad- 

 smelling combinations originate are not properly known ; 

 but it is probable that they are developed with, and 

 under the same conditions that cause the formation of, 

 ammonia, as the disagreeable pungent flavour is found 

 generally in tobacco that has undergone fermentation to 

 a great extent. It is believed that the conditions that 

 favour the development of nicotine are also conducive 

 to the formation of albuminous substances in the leaf, 

 viz. fresh nitrogenous manure, bad physical state of the 

 soil, &c. 



According to Nessler, the quality of tobacco depends 

 to a great degree on the amount of cellulose it contains. 

 He found that a good tobacco invariably contained more 

 than a bad one, Havana yielding as much as 46 per cent. 

 The fact that tobacco burns better after being stored for a 

 time may be partly due to an increase of cellulose 

 in it. 



Every tobacco contains more or less fat, gum, ethereal 

 oil, &c. It is not properly known in what way fatty 

 matters affect the quality of tobacco. Many other 

 organic matters exist in tobacco in combination with 

 substances from which it is most difficult to separate 

 them; they have not as yet been quantitatively ascer- 

 tained, and are therefore little known. Most of them 

 are only developed during the drying and fermenting 



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