ng of banana leaves keeps the beans warm.]

The planter decides when the beans are fermented by simply looking at
them; he judges their condition by the colour of the pulp. When they are
ready to be removed from the fermentary they are plump, and brown
without, and juicy within.

(_b_) _Changes in the Interior of the Bean._--What is the relation
between the comparatively simple fermentation of the pulp and the
changes in the interior of the bean? This important question has not yet
been answered, although a number of attempts have been made.

As far as is known, the living ferments (micro-organisms) do not
penetrate the skin of the bean, so that any fermentation which takes
place must be promoted by unorganised ferments (or enzymes). Mr. H.C.
Brill[2] found raffinase, invertase, casease and protease in the pulp;
oxidase, raffinase, casease and emulsinlike enzymes in the fresh bean;
and all these six, together with diastase, in the fermented bean. Dr.
Fickendey says: "The object of fermentation is, in the main, to kill the
germ of the bean in such a manner that the efficiency of the unorganised
ferment is in no way impaired."

[2] _Philippine Journal of Science_, 1917.

From my own observations I believe that forastero beans are killed at 47
degrees C. (which is commonly reached when they have been fermenting 60
hours), for a remarkable change takes place at this temperature and
time. Whilst the micro-organisms remain outside, the juice of the pulp
appears to penetrate not only the skin, but the flesh of the bean, and
the brilliant violet in the isolated pigment cells becomes diffused more
or less evenly throughout the entire bean, including the "germ." It is
certain that the bean absorbs liquid from the outside, for it becomes so
plump that its skin is stretched to the utmost. The following changes
occur:

(1) _Taste._ An astringent colourless substance (a tannin or
a body possessing many properties of a tannin) changes to a
tasteless brown substance. The bean begins to taste less
astringent as the "tannin" is destroyed. With white (criollo)
beans this change is sufficiently advanced in two days, but
with purple (forastero) beans it may take seven days.

(2) _Colour._ The change in the tannin results in the white
(criollo) beans becoming brown and the purple (forastero)
beans becoming tinged with brown. The action resembles the
browning of a freshly-cut apple, and has