146 The Fermentation of Cacao 
time. This phenomenon led one to suppose 
that the action was due to the working of 
enzymes. 
It is difficult to give a concise, and at the 
same time a good definition of what is under- 
stood by an enzyme, but, speaking generally, 
one may say that enzymes are substances of 
vegetable or animal origin, which have’ the 
power of causing reactions between certain 
substances, without themselves playing any 
part in the composition of the substances 
formed by the said reaction; they are thus 
able, in minute quantities, to manipulate the 
decomposition of great quantities of these same 
substances; the enzymes are made harmless at 
a temperature of 100° C., most of them at a 
lower temperature still, viz., between 65°C. 
and 70° C., while the temperature at which the 
enzymes exhibit the greatest activity (the so- 
called optimum temperature) lies, for the most 
part, between 45°C. and 60°C. As regards 
the chemical composition of the enzyme nothing 
‘is known so far. 
In order to be positively: certain that the 
discolouration is actually due to the presence of 
an enzyme, attempts were made to isolate same. 
This was done as follows: The cacao beans 
were thoroughly washed with water, so as to 
remove the sugars, acids, &c., whereupon -they 
were crushed to pieces, and steeped into alcohol 
so as to be able to remove the seed pellicle 
easily. The seed pellicle contains much slime, 
