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«ition of the leaves, which only appears and becomes capable of working 

 mischief when sufficient moisture is present. According to Sturgiss, 

 this is caused by bacteria, which swarm on the leaves, among which 

 two forms were invariably found in company, one a rod-shaped organism 

 and the other a micro-coccus. Careful observation of healthy dry leaves, 

 which were brought into a room saturated with moisture, shewed that 

 the disease progressed in the following mancer : first, small, brown 

 patches caused by a Cladosporium were found here and there on the 

 leaves ; at the expiration of some weeks, this organism which did not 

 multiply further, died off, and in its place appeared the above-men- 

 tioned bacterium. The author considers this pole burn to be primarily 

 due to the presence of a mycelium, which partially destroys the leaf 

 cells and thus allows of the entrance of putrescent bacteria into the tis- 

 sues, and it is owing to this that the otherwise harmless Cladosporium 

 becomes harmful. The remedy is self-evident, from the fact that in 

 dry air the leaves are not attacked. Finally, the hastening of the dry- 

 ing process by artificial heat is indicated. 



A disease called " Stem-Rot," which Sturgiss examined, is also men- 

 tioned. It appears on the stems of the tobacco leaves when hung up to 

 diy. At first, a pure white, satin-like mildew appears on the stems, 

 consisting of the mycelium of a Botrytis which the author identifies 

 with Botrytis longibrachiata, Oudem. This fungus destroys the 

 fibre and especially injures the leaves by inducing a foul 

 decomposition. When the tobacco is ripe and has passed into the 

 hands of the manufacturers, it is subjected to a so-called " fermentation 

 process," which is brought about by putting the tobacco bundles into 

 great heaps, on which the whole mass becomes warm. That this spon- 

 taneous heatiDg is due to the activity of micro-organisms was formerly 

 more a matter of conjecture than actual knowledge. The temperature 

 in the middle of the heaps varies very much ac ording to circumstances. 

 The more the loss of heat is prevented externally, the greater, up to a 

 certain point, will be the temperature in the middle of the heaps. Con- 

 sequently, big heaps become warm quicker and easier than small ones. 

 It is self-evident that a certain amount of heat and moisture is necessary 

 to the commencement of the fermentation, In practice Xessler has re- 

 corded in the middle of the heaps a maximum temperature of 135*5 Q P. 

 Suchsland that of 141 ■ 8° F. As a rule the temperature is not allowed 

 to rise higher that 122° F., the heaps are then taken asu? der and built 

 up again, care being taken that the outside of the heap is in the middle. 

 This turning over is repeated until the whole mass is thoroughly fer- 

 mented. Regarding the aim of the fermenting process, nothing very 

 definite is known up to the present time. This much is certain that the 

 fermentation improves the appearance and aroma of the tobacco, and 

 perhaps it is only then that it becomes durable and transportable. The 

 most important chemical change during fermentation consists in the 

 loss of nicotine, about 24 to 28 per cent, of the original quantity disap- 

 pearing. Behrens, who in his researches showed that the nicotine is not 

 present in a free state, either in fermented or unfermented tobacco, but 

 in a non- volatile combination, considers it probable that part of the ni- 

 cotine is used up by the organisms of fermentation for their nutriment. 

 He even proved by an experiment, under not too favourable conditions, 

 that the mould Botrytis cinerea was able to supply itself with the ne- 



