Aq 
fungi find it rather difficult to live under those conditions.' In reality 
the conditions are still much less favorable for bacteria than we have 
assumed in this calculation. The high temperature is also an obstacle 
to most bacteria. Fermenting wrapper leaves sometimes reach a tem- 
perature of 60° C. (140° F.), and still ferment again when the heap is 
repacked. It would be a very easy matter to isolate the active bacteria, 
if they should belong to the few thermophylic kinds that can be active 
in such a high temperature. But nine yeais have passed since the 
promulgation of the bacterial theory of tobacco fermentation, and thus 
far there is nowhere to be found a scientific description of the supposed 
tobacco bacterium. 
The following experiment shows that bacteria from the very surface 
of the tobacco leaves can not thrive in a concentrated tobacco extract. 
Such an extract containing 30.2 per cent of sotid matter was sterilized 
and a small piece (about 1 cm. square) of a freshly cured tobacco leaf? 
introduced, after which the flask was plugged with cotton. After 10 
days neither a seum nor a turbidity indicating the presence of bacteria 
could be noticed, but some clot-like masses were observed. ‘These 
masses proved to consist of a mycelium of a fungus, while even with 
the highest magnifying power no microbes could be observed. How- 
ever, a dilute solution, prepared by diluting the former with ten times 
its volume of water, formed a bacterial scum within two days upon 
exposure to the air. 
In a second trial, with a concentrated solution of 25 per cent of 
tobacco extract (contained in a test tube) exposed to the air for ten days 
to admit various kinds of microbes, there was neither a scum nor a 
bacterial turbidity produced. On microscopical examination, however, 
some few bacteria could be noticed. Now, if solutions of such concen- 
trations are so very unfavorable for bacterial growth, how much more 
must this be the case for the much higher concentration to be found in 
the cells of the fermenting wrapper leaves? 
Further experiments proved that even at a water content of 35 and 
40 per cent present in fermenting fillers* bacteria can not flourish upon 
the leaf surface at the temperature of the fermenting piles. In freshly 
cured heavy tobacco the water was determined and enough water added 
so that in two samples the percentage reached 35 and 40 per cent, 
respectively. These leaves were rolled up and placed in flasks, which 
were sealed with paraffin and kept for five days at a temperature of 
from 53° to 55° C., there being an abundance of air in the flasks. For 
1 According to Splendore (Revista Tecnica, Roma, 1899), Ocspora Nicotiane can not 
develop upon tobacco that hag less than 26 per cent of water, and, according to 
Behrens (Landw. Vers. Stat., Aug., 1899), Botrytis requires at least 30 per cont of 
water in cured tobacco to be able to grow on it. 
2This tobacco contained catalase, oxidase, and peroxidase and was subjected to 
“sweating” or “‘fermentation in bulk.” It sweated normally. 
* Hands of filler tobacco are dipped with their base deeper into the water than 
hands of wrapper tobacco, thus securing a higher water content. 
