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possess certain characters. A fresli leaf has no specific taste, nor lias 

 it any specific odor, but the finished leaf has a sharp, saline taste and 

 a characteristic odor. 



From the time the tobacco leaf is gathered in the field until the 

 manufacture of the cigar and even afterwards a series of highly inter- 

 esting changes take place in the leaf, as a result of which the charac- 

 ters of the finished leaf are developed and fixed. There are three 

 stages in these changes, viz, (1) the curing i3rocess; {'2) the sweating, 

 or fermentation; and (3) the cold sweat, after-fermentation, or aging, as 

 it IS variously called. 



THE CURING. 



There are two periods in the curing process: The first i)eriod, in 

 which the cells of the leaves are still alive and induce processes of 

 metabolism; and the second period, in which the cells have died and 

 the chemical changes have therefore no connection with the living 

 protoplasm. In the former i^eriod, which may last only a few days 

 (longer with the ribs), the starch content is dissolved and the sugar 

 formed is partly consumed by an increased respiration^ and iiartly 

 transported to the ribs, where, as Miiller-Thurgau has shown, starch 

 may be formed again. In the latter j)eriod the enzyms alone are active. 



Decrease of protein. — With the consumption of a large amount of the 

 sugar a state of inanition or starvation sets in, and the reserve protein 

 is attacked by an enzym, trypsin-like in character, the action of which 

 will continue after the death of the cells. A cold-prepared aqueous 

 extract of a fresh leaf will show albumin on the addition of nitric acid 

 and warming, w^hile the cured leaf does not give this reaction. The 

 reserve protein and a certain albuminous portion of the nucleo-proteids 

 of the protoplasm will thus finally be split and transformed into amido 

 compounds and bases, only the remaining nucleins resisting, hence the 

 decrease of protein matter in the curing and fermentation process will 

 stop at a certain point. Such proteolytic processes proceed not only 

 in plants exposed to darkness, which means their starvation or inani- 

 tion, but also in all cases where reserve protein must be dissolved to 

 enable further development, as in germination or development from 

 bulbs. 



It is in full accordance with physiological principles that when cells 

 are in want of nourishment they produce a larger amount of enzyms 

 than when well nourished. This explains why tobacco leaves killed 

 immediately after being gathered will show imperfections when after 

 having been moistened they are subjected to the curing process. The 

 enzyms that have been produced during the inanition state of the 



^ The respiration of a pile of such fresli leaves may soon lead to a considerable and 

 even injurious rise of temperature, as in the respiration of germinating barley on t^e 

 saaltine floor. A moderate rise is often intentionally brought on, as it hastens 

 tbpi curing. Sometimes this rise of temperature is called sweating, although the 

 cause here is a different one from the true sweating, or fermentation, following 

 after curing. 



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