FERMENTATION OF TOBACCO. 161 



assumption that these play a part in producing the successive 

 alterations in the leaf material. During fermentation the 

 temperature gradually rises, and it is attempted in various 

 ways to limit the temperature to about 50 C. The effect of 

 fermentation is that aromatic bodies are produced in the 

 leaves, and simultaneously part of the nicotine, according to 

 Behrens, disappears. Suchsland was the first to investigate 

 the micro-organisms present in fermenting tobacco. He 

 attempted to improve its quality by introducing pure cultures 

 of selected species of bacteria. Nothing further is known 

 with regard to these species. More recently, Behrens, Vern- 

 hout, Koning, and others have described some of the vast 

 number of species that are present, and Koning found by 

 parallel experiments that an inoculation with certain pure 

 cultures selected from fermenting tobacco, partly aerobes, 

 but chiefly facultative anaerobes, exercised a favourable 

 influence on the aroma and flavour of the tobacco. In the 

 same way the after-fermentation, which takes place when the 

 leaves are packed together, appears to be due to the action of 

 micro-organisms. A contrary view has been expressed by 

 0. Loew, who attaches no importance to micro-organisms 

 in the fermentation, but seeks the active causes in the oxidising 

 enzymes, which he proves to be present in the leaves. H. 

 Jensen, as well as Splendore, found that leaves which had been 

 heated in a current of steam (90- 100 C.) showed every 

 sign of a good fermentation, and that this was not prevented 

 by treatment of the leaves with mercuric chloride, formol, 

 and chloroform, which certainly appears to confirm Loew's 

 conclusion. Behrens bases upon his observations the belief 

 that micro-organisms play a part in the fermentation, a view 

 the correctness of which is rendered more probable by the 

 results of Schloesing's experiments on the fermentation of 

 snuff tobacco. The experiments undertaken in the author's 

 laboratory with parallel fermentations carried out with both 

 American and African tobacco lead to the conclusion, especially 

 when facultative anaerobes are employed, that certain species 

 do play a part in determining the aroma and flavour of 

 tobacco. 



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