TOBACCO 237 



three changes. In fact, Suchsland, the originator of this view, isolated 

 some of these bacteria from Havana tobacco, and introduced them into 

 the fermenting leaves of German tobacco. No practical results have, 

 however, been yet achieved by this mode of procedure. Other investi- 

 gators, following these lines, have described the various bacteria 

 concerned in fermentation. These are Bacillus mycoides and Bacillus 

 subtilis, two very common species, as well as five new kinds, named 

 respectively Bacillus tobacci I., II., III., IV., V. One or more of 

 these are supposed to be present among, and to be responsible for all 

 the changes that take place in the fermenting leaves. 



A third view, which finds most favour, is that certain chemical sub- 

 stances are present in the leaf, which are capable of exercising a very 

 strong oxidising action. All the changes are claimed to be due to the 

 oxidations of these substances. They are also claimed to be oxidising 

 enzymes. Loew's experiments prove beyond a doubt that such oxidis- 

 ing agents are present in the leaf, and that the great heat developed by 

 fermenting leaves is mainly due to them. His experiments do not, 

 however, prove that they produce all the changes, and it is still a matter 

 of doubt whether the aroma and flavour, which are the most important 

 factors, are due to them. If we assume the presence of bacteria, it 

 becomes easier to explain why it is that different kinds of tobacco have 

 such different flavours, for the bacteria found on the tobacco leaves of 

 different countries would naturally not belong to the same species. 

 The practice of petuning lends colour to this supposition. By 

 this process a liquid is sprayed on the fermenting leaves either 

 during or after the fermentation process. The petuning liquid is 

 supposed to give the peculiar flavour to Cuban tobacco. Its composition 

 is kept a secret. The changes described by Loew take place in all 

 fermenting tobacco leaves. All that can be said at present is that 

 the r61e of bacteria in the fermenting of tobacco has not yet been 

 determined. 



§7. INDIGO. 



This dye is obtained from a number of leguminous plants, native to 

 the East and West Indies, the best known being Indigofera tinctoria. 

 The plants are placed in cisterns, and kept at 25''-35° C. for 8-15 hours. 

 The glucoside indican, which is contained in them is transformed, 

 through the activity of a special bacillus which is found on the leaves, 

 into indigo-white, and a sugar called indigo-glucin. On the surface of 

 the water, however, the colour, instead of being of a greenish yellow 



