Dr. J. Sack 143 
The phases of the external fermentation, as 
observed with the tests described, may be 
contained in the following :— 
Immediately the seeds are placed in the 
sweating-boxes, the fungi and bacteria sur- 
rounding them, and which are to be found 
upon the cacao, change the sugar out of the 
pulp into alcohol, thence into acetic acid, 
subject to the necessary development of heat. 
To what form of life they belong may be 
gauged with a tolerable degree of certainty, 
as the changing of sugar into alcohol, thence 
into acetic acid, is a well-known process. 
The decomposition of sugar into alcohol 
is probably due to a fermentation fungus ; 
from sugar and water there arise alcohol and 
carbonic acid gas. 
The decomposition of alcohol into acetic 
acid is probably caused by a certain kind of 
bacteria. It is an oxidation process, that is 
to say the alcohol unites in this way with 
oxygen, and that according to the following 
formula :— 
C,H,O + O, = C,H,O, + H,0. 
Alcohol Oxygen Acetic acid Water 
Consequently oxygen is required for this 
decomposition, which is the reason why, as 
we could see from the test on page 140, 
the fermentation needs the action of the air. 
With the decomposition of the alcohol into 
acetic acid heat develops. 
