A certain amount of fermentation takes place 
in the curing houses during the “yellowing” of 
the leaf after it has been harvested, but as we 
have seen the main process of fermentation does 
not occur until it is “rehandled” by the manu- 
facturers. 
The general opinion held at present as the 
result of investigation is that the transforma- 
tions which are effected in the leaf are purely 
the result of chemical processes. As the plant 
slowly dies and decomposes special ferments 
are produced. These ferments set up an oxi- 
dization process which splits up the complex 
organic compounds which still exist in the leaf 
cells. The starch in the plant is changed into 
sugar which is slowly consumed. There is a de- 
crease in the fats and gummy substances, also 
in nicotine and nitrogenous compounds, and 
there is a formation of certain organic acids 
such as malic, citric and oxalic which are 
essential in the production of flavor. Briefly it 
may be said that the process is an attempt by 
the plant to prolong its existence by feeding on 
its own substance, by drawing on its own re- ( 
serves and on its own structure for the food 
which its cells no longer receive through the 
natural growing process. When the struggle 
is over the “fermentation” is complete. The 
necessity for maturing tobacco has long been 
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