some circumstances it may be lactic acid, or the rancid-smelling butyric
acid. Kismet! The planter trusts to nature to provide the right kind of
fermentation. This fermentation is set up and carried on by the minute
organisms (yeasts, bacteria, etc.), which chance to fall on the beans
from the air or come from the sides of the receptacle. One yeast-cell
does not make a fermentation, and as no yeast is added a day is wasted
whilst any yeasts which happen to be present are multiplying to an army
large enough to produce a visible effect on the pulp. _Any_ organism
which happens to be on the pod, in the air, or on the inside of the
fermentary will multiply in the pulp, if the pulp contains suitable
nourishment. Each kind of organism produces its own characteristic
changes. It would thus appear a miracle if the same substances were
always produced. Yet, just as grape-juice left exposed to every
micro-organism of the air, generally changes in the direction of wine
more or less good, so the pulp of cacao tends, broadly speaking, to
ferment in one way. It would, however, be a serious error to assume that
exactly the same kind of fermentation takes place in any two
fermentaries in the world, and the maximum variation must be
considerable. As the pulp ferments, it is destroyed; it gradually
changes from white to brown, and a liquid ("sweatings") flows away from
it. The "_sweatings_" taste like sweet cider. At present this is allowed
to run away through holes in the bottom of the box, and no care is taken
to preserve what may yet become a valuable by-product. I found by
experiment that in the preparation of one cwt. of dry beans about 1-1/2
gallons of this unstable liquid are produced. In other words, some seven
or eight million gallons of "sweatings" run to waste every year. In most
cases only small quantities are produced in one place at one time. This,
and the lack of knowledge of scientifically controlled fermentation,
and the difficulty of bottling, prevent the starting of an industry
producing either a new drink or a vinegar. The cacao juice or
"sweatings" contains about fifteen per cent. of solids, about half of
which consists of sugars. If the fermentation of the cacao were
centralised in the various districts, and conducted on a large scale
under a chemist's control, the sugars could be obtained, or an alcoholic
liquid or a vinegar could easily be prepared.

[Illustration: CHARGING THE CACAO ON TO TRUCKS IN THE PLANTATION, SAN
THOME.]

[Illustration: CACAO IN THE FERMENTING TRUCKS, SAN THOME.
The covering 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 been shown to be due
    to oxygen (activated by an oxidase, a ferment encouraging
    combination with oxygen) acting on the astringent
    colourless substance, which, like the photographic developer,
    pyrogallic acid, becomes brown on oxidation.

    (3) _Aroma._ A notable change is that substances are created
    within the bean, which _on roasting_ produce the fine
    aromatic odour characteristic of cocoa and chocolate, and
    which Messrs. Bainbridge and Davies have shown is due to a
    trace (0.001 per cent.) of an essential oil over half of
    which consists of linalool.[3]

    (4) _Stimulating Effect._ It is commonly stated that during
    fermentation there is generated theobromine, the alkaloid