51 
its characteristic odor. ‘Nicotine free” cigars made of such tobacco 
’ are also devoid of any trace of aroma. Treatment with much alcohol 
also removes the odor more or less, and this alcoholic extract on evapo- 
ration at the ordinary temperature leaves a residue recalling the odor 
of the tobacco. This residue upon treatment with ether can be sepa- 
rated into a soluble and an insoluble part, but neither of these has any 
odor, Showing that the substances which caused the odor are easily 
volatilized or chemically changed. Indeed, they are easily changeable, 
as can be observed when sweated tobacco is distilled with water. Five 
hundred and fifty grams of Florida tobacco of a superior odor were 
mixed with eight times its weight of water and nearly 500 c.c¢. were 
distilled off. On the surface of the slightly turbid distillate, which had 
a weak but rather disagreeable odor, resembling somewhat that of ran- 
cid oils, minute oil drops were seen. Not only was the distillate devoid 
of any specific odor, but also the contents left in the flask had lost the 
original odor. The odor is also easily removed by dry heat. Two 
hours exposure to air at a temperature of 100° C. (212° F.) suffices to 
deprive tobacco of most agreeable odor of this desirable quality. 
Tobacco leaves, even from the best tobacco regions, are by no means 
distinguished by peculiar flavor in their fresh or cured state.’ The 
curing exerts a beneficial effect upon the quality of the aroma only in 
so far as a part of the protein is destroyed by it. Cured tobacco, even 
from the best sources, has a mere straw odor. The fine odor and genu- 
ine aroma are generated by the sweating process. The better regulated 
the sweating process, the finer the aroma, other things being equal. 
Whenever the sweat is not proceeding well—-ascribed sometimes to a 
high fat content, or perhaps caused by imperfect curing, or by inju- 
ries to the oxidizing enzyms in the curing barn—the product will have 
a poor aroma. These circumstances make it clear that the original 
resin in the leaves can not be the cause of the aroma, as some authors 
have surmised. Indeed, the resinous matter from fresh or cured leaves 
does not show any particular flavor when heated; neither has the ethe- 
real oil contained in the hairs of the fresh leaves a beneficial effect on 
the quality of the tobacco. 
It is well known that it is especially the so-called gummy leaves that 
sweat best and give the finest aroma. Such leaves are found among 
- the upper and not among the lower or sand leaves, and are very rich in 
extractive matters. When such leaves are shrinking in the process of 
drying in the curing process, these soluble inatters may sometimes be 
forced to the surface, to some extent, in the form of a concentrated solu- 
‘While the juice of fresh tobacco leaves assumes, after a short time, the odor of 
cucumbers, fresh leaves dried at 50° C., and afterwards moderately warmed with 
water, gradually develop the agreeable odor of dried malt; an interesting fact, since 
the germinating barley on the malting floor also at first develops the odor of cucum- 
bers. 
