1 68 THERMOGENIC BACTERIA. 



while FESCA and IMAI (I.) ascertained that nitrates are no longer 

 present in the fermented mass. The amount of nicotine is also re- 

 duced, only 70 per cent, of that originally present being afterwards 

 found (in one experiment) by Behrens. 



The flora of the fermenting tobacco heap does not consist solely 

 of bacteria. For example, JOH. BEHRENS (III.) frequently met 

 with the Aspergillus fumigatus already mentioned, and Davalos 

 and Behrens also very often detected Monilia Candida, remarks 

 on which will be given in a subsequent chapter. 



A few researches have been made into the fermentation of 

 snuff, the most important being those carried out by TH. SCHLOS- 

 ING (I. and II.) relative to the chemical changes involved. With 

 respect to the part played by micro-organisms he expressed himself 

 as follows: "The fermentation begins at the ordinary tempera- 

 ture under the predominant influence of micro-organisms, but above 

 a certain (still to be determined) limit, which is over 40 C. and 

 below 70 C., and is probably about 50 C., the changes become 

 purely chemical reactions in which the living organisms have no 

 longer any share." When giving utterance to this opinion Schlos- 

 ing was unacquainted with the newer researches in connection 

 with the heat-loving organisms which thrive at 70 C. It is 

 therefore desirable that his experiments should be repeated and 

 extended, with this fact borne in mind. 



The tobacco subjected to this fermentation is usually moist- 

 ened with a liquid containing sugar, syrup, honey, and the like, 

 in addition to various aromatics, and not infrequently alcohol 

 as well. In many cases this "sauce" also has added to it wine 

 yeasts, particularly for the grades known as St. Omer, St. Vincent, 

 and Paris tobaccos. These additions (found by experience to be 

 partly essential and partly useful) probably furnish the material 

 for, on the one hand, a weak alcoholic fermentation, and, on the 

 other, for the formation of esters. More detailed knowledge is, 

 however, lacking with regard to this primary fermentation, and to 

 the subsequent after-fermentation of the tobacco, either packed 

 tightly into casks or rolled up in "pigtail" form and wrapped in 

 linen cloths. The snuff yielded by the latter method is finer than 

 that obtained by the quicker cask-fermentation process. More 

 definite researches on this subject are highly desirable. 



106. The Preparation of Burnt Hay 



must also be briefly described in this place. There are two chief 

 methods, differing from one another, for the preservation of green 

 fodder, viz., either by acidifying it, allowing it to ferment, and so 

 producing "sour" fodder or ensilage for which see also Chapter 

 xxvi. ; or it is dried and then forms hay. The removal of the 

 water, of which the plants now under consideration contain some 

 85 per cent., can be effected in two different ways. Either the 



