238 The Fermentation of Cacao 
These bodies tend to disappear if the beans 
are kept for a length of time. Perhaps a few 
others are formed, in which case the beans (all 
else being equal) would improve with keeping. 
Summary of the Changes which take place. 
(1) The testa is rendered ‘more brittle and 
acts as a diffusion membrane. Cacao red and 
other constituents diffuse into it. 
(2) ,The kernels assume a diffuse chocolate 
colour, are plumped up and become less ad- 
herent to the testa; this is the action of the 
volatile substances and the carbonic acid gas, 
(3) The sugar and, to some extent, the starch 
are converted to lower products, such as alcohol, 
acetic acid and carbonic acid gas. 
(4) The fats are lost’to a very slight extent. 
(5) Theobromine and cacao red are also very 
slighnly lost. 
(6) Some of the bitter principle is reduced or 
diffuses out of the bean. 
(7) Acetic acid and alcohol become present 
in the kernel. 
The Isolation and Cultivation of the Organisms 
which Ferment Cacao. 
The principle of the cultivation of organisms 
is to provide them with a medium which con- 
tains only food material and substances which 
are favourable to them. 
The medium must vary with different classes 
of organisms: thus yeasts will flourish upon 
saccharine media in which there is an absence 
