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, 



