Nor is this simply a matter of inference.  To a certain extent experimental evidence has borne out the conclusion, and has given at least a slight indication of practical results in the future.  Acting upon the suggestion that the difference between the high grades of tobacco and the poorer grades is due to the character of the bacteria that produce the fermentation, certain bacteriologists have attempted to obtain from a high quality of tobacco the species of bacteria which are infesting it.  These bacteria have then been cultivated by bacteriological methods and used in experiments for the fermentation of tobacco.  If it is true that the flavour of high grade tobacco is in large measure, or even in part, due to the action of the peculiar microbes from the soil where it grows, it ought to be possible to produce similar flavours in the leaves of tobacco grown in other localities, if the fermentation of the leaves is carried on by means of the pure cultures of bacteria obtained from the high grade tobacco.  Not very much has been done or is known in this connection as yet.  Two bacteriologists have experimented independently in fermenting tobacco leaves by the action of pure cultures of bacteria obtained from such sources.  Each of them reports successful experiments.  Each claims that they have been able to improve the quality of tobacco by inoculating the leaves with a pure culture of bacteria obtained from tobacco having high quality in flavour.  In addition to this, several other bacteriologists have carried on experiments sufficient to indicate that the flavours of the tobacco and the character of the ripening may be decidedly changed by the use of different species of micro-organisms in the fermentations that go on during the curing processes.

In regard to the whole matter, however, we must recognise that as yet we have very little knowledge.  The subject has been under investigation for only a short time; and, while considerable information has been derived, this information is not thoroughly understood, and our knowledge in regard to the matter is as yet in rather a chaotic condition.  It seems certain, however, that the quality of tobacco is in large measure dependent upon the character of the fermentations that occur at different stages of the curing.  It seems certain also that these fermentations are wholly or chiefly produced by microorganisms, and that the character of the fermentation is in large measure dependent upon the species of micro-organisms that produce it.  If these are facts, it would seem not improbable that a further study may produce practical results for this great industry.  The study of yeasts and the methods of keeping yeast from contaminations has revolutionised the brewing industry.  Perhaps in this other fermentative industry, which is of such great commercial extent, the use of pure cultures of bacteria may in the future produce as great revolutions in methods as it has in the industry of the alcoholic fermentation.