a certain number of secret receipts for
restoring dead pearls to their primitive lustre. In one of these
concoctions there are eighty-three ingredients, each one more whimsical
than the last. In another the chief ingredient is dew gathered under
certain conditions, and from the leaves of certain plants. One easily
traces the influence here of the idea that the ancients entertained of
the origin of the pearl.
At
first glance these receipts seem only to associate the most dissimilar
elements, and those that could not possibly have any efficacy; but the
chemist discovers in them one remarkable fact: after the complex
reactions of one substance upon another, there remains always the
definite result of an acid liquor.
Recalling
now the constitution of the pearl, formed of concentric layers, and the
facility with which it is dissolved by an acid liquid, one can easily
see that a pearl plunged into this liquor will be attacked, and that
its exterior layer will quickly disappear. If the pearl submitted to
this operation is only yellow and opaque exteriorly, the removal of the
layer thus modified will leave bare the normal layers, and the pearl
will recover its lustre. If, on the contrary, the layers are
discoloured and opaque to the centre, nothing can restore it. In the
first case the operation is a success; in the second it is a failure.
The reason is no longer a mystery.
