Dr. Oscar Loew 53 
on the bean and affects its flavour, the bean 
being, as may be said, ‘stewed in its own 
juice.’” 
According to the laws of osmosis some acetic 
acid and some alcohol from the fermenting 
liquor will doubtless enter through the testa 
and come in contact with the cotyledons, which 
thereby may be killed, if the temperature of 
the fermenting mass has not already accom- 
plished this. The reaction of the cotyledons 
after drying the fermented beans is acid, but 
whether this is wholly due to the entering 
acetic acid may be doubtful, since the reaction 
is weakly acid in the fresh state. A stronger 
acid reaction is shown by the slime tissue. 
The expression “stewed in its own juice” 
used by Chittenden can hardly be admitted, 
since the juice of the pulp, after being entirely 
decomposed by yeast and bacteria, is certainly 
not the ‘‘own juice” of the cotyledons. Still, 
that author attributes to it the generation of 
the flavour, 
The opinion of Prof. Harrison (see p. 36) 
that the decrease of tannin during the fermen- 
tation process stands in relation to the develop- 
ment of the aroma (see p. 37) is certainly far 
from the mark, as tannin cannot produce 
ethereal oils by any oxidation or fermenting 
process. Only colour and taste stand in this 
relation to the tannin content. 
Several experiments were made by the 
writer with an aqueous solution of 1 to 4 per 
