Dr. J r Sack 143 



The phases of the external fermentation, as 

 observed with the tests described, may be 

 contained in the following : 



o 



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 2 H 6 + 2 -= C 2 H 4 2 + H 2 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. 



