232 The Fermentation of Cacao 



which falls when most of the sugar is converted 

 into these two bodies. 



This produces important changes in the 

 testa and kernels of the seeds ; some of these 

 are obvious, and others are shown by careful 

 examination and analysis. The first question 

 to decide is exactly how these changes take 

 place, and in what way substances pass the 

 exterior and the interior of the seed. 



If fresh beans covered by their pulp, and 

 other beans in various stages of fermentation, 

 are placed in different solutions of salts or 

 other chemicals, removed at various times, 

 washed well in distilled water, and their kernels 

 carefully extracted and analysed, these chemi- 

 cals will be found to be present ; the amount 

 that has reached the kernels depends on the 

 degree of fermentation that the beans have 

 undergone ; fermented beans have a far greater 

 proportion of these, i.e., alcohol and acetic 

 acid, in their interiors than unfermented beans. 



From this it is shown that the fresh sac- 

 charine pulp and testas allow but limited pene- 

 tration, whereas the testas of fermented beans 

 have become good diffusion membranes, 

 allowing matter in solution to pass freely to 

 and from the kernels. It was at one time 

 thought that whatever passed into or out of 

 the bean did so by the hilum ; this may occur 

 to some extent, but that the whole testa acts 

 as a diffusion membrane is shown by the 

 following experiment : Beans were soaked for 



