13 



One author has assumed that the chlorophyll is first attacked in the 

 curing' process and destroyed, but this is not correct. The green color 

 of the chlorophyll is in the beginning merely covered by the brown 

 substances. In the thin samples of fermented leaves of a light brown 

 color green spots may frequently be noticed, and even dark-colored, 

 freshly fermeuted leaves may sometimes yield a greenish solution upon 

 extraction with strong alcohol. It is of some interest to note that the 

 brown matters are insoluble in absolute alcohol. 



Ammonia. — An interesting feature in the curing and fermenting 

 process is the formation of a small amount of ammonia. As the green 

 leaves contain some asparagin, the formation of ammonia might be due 

 to a small extent to the decomposition of this amide, which readily 

 yields ammonia and aspartic acid. But in certain tobacco crops there 

 occur only minute quantities of asparagin. Certain amido compounds 

 formed by decomposition of jjroteids and also a part of tbe nicotine in 

 decomposing probably yield the principal amount of ammonia. The 

 nicotine undergoes, in the fermentation process at least, a considerable 

 diminution, as explained below. 



The opinion that the ammonia deteriorates the quality of the product 

 is certainly unfounded, as Fesca has correctly pointed out. It has been 

 demonstrated by Behrens that during the curing ]n'ocess a part of the 

 sulphur of the decomposed proteids is oxidized to sulphuric acid and 

 that the amount of compounds soluble in ether decreases. The latter 

 consist of a fatty substance and a volatile oil of disagreeable odor 

 derived principally from the gland hairs. 



The total loss of dry matter in the curing i)rocess is subject to great 

 variation, depending mainly upon the amount of starch present at the 

 time of gathering, as above stated. The diminution of dry matter may 

 be as much as 40 per cent. 



The i)rincipal changes in the curing process may be summed up as 

 follows : 



(1) Disappearance of starch. 



(2) Formation of sugar and its partial disappearance by respiration. 



(3) Decomposition of protein with formation of amido compounds. 

 (I) Decrease of fatty matter. 



(5) Decrease of tannin. 



(6) Change of color and flavor. 



THE SWEATING OR FERMENTATION PROCESS. 



The so-called fermentation process develops in the tobacco leaves the 

 characteristic qualities of the commercial article. It is natural to sup- 

 pose that the same agency which finishes the curing x^rocess after the 

 death of the cells remains active during the so-called fermentation 

 l^rocess also. The fermentation follows immediately after the curing 

 when both are done by the grower, but wliere the cured tobacco is 

 bought ui) by manufacturers several months may pass before it is sub- 



