72 The Fermentation of Cacao 
to set in again from the surface downwards. 
All these results will probably lead to the 
acknowledgment that an oxydase assists in 
producing the brown colouration of the beans, 
and that this is brought about by the oxidation 
of the tannic substances. Whether a decom- 
position of the glucosides takes place prior 
to oxidation has still to be investigated and 
ascertained. The behaviour of beans with a 
whitish break, z.e., Criollo beans, differs from 
the beans having purple cotyledons, z.¢., of the 
Forastero. variety, inasmuch as the devitalizing 
temperature is 5° to 10° higher (for Criollo 
beans), but in other respects the conditions 
are the same. Here, again, we have the same 
tannic substances formed in the white cells, 
as can be proved if sections of the beans are 
examined. Under the -microscope the cells 
containing the tannic substances can be 
distinguished in the purple (Forastero) beans, 
on account of the purple-coloured matter 
they contain, which matter also is of a tannic 
character. 
Comparing the results of all these experi- 
ments led to the discovery that the oxida- 
tion of tannic substances increases very quickly 
in weak alkaline and neutral reaction, and that, 
on the other hand, with an increased propor- 
tion. of .acid, the influence of the oxydase 
diminishes to a corresponding degree. The 
concentration of the acid which is noticeable 
in the pulp (some yy to 2 normal) causes, 
