crude
fancies and curious fables have gradually passed away. It is the object
of the present chapter to present a rational explanation of the origin
and formation of Pearls, so far as the lights of our present knowledge
can guide us in solving these difficult problems.
For
a long time it was currently believed that Pearls were found only in
diseased shell-fish, and to this day in some parts of Great Britain,
when a Pearl is discovered in a mussel ór oyster, the edible part is
thrown away as unfit for use, while the Pearl, however valueless, is
carefully preserved. Hence we often find, even at the present day, that
Pearls are alluded to as " morbid secretions."
On
this subject, Professor Coutance, of the Medical School of Brest, has
some remarks which are at once sensible and amusing :—" Au point de vue
physiologique, l'huître ne fait, en produisant la Perle rien d'anormal,
puisque la nacre de la coquille est formée de la même substance. Elle
ne tire de son fond aucune matière nouvelle poure faire la Perle : elle
y emploie seulement, peut-être au préjudice de sa coquille, une part de
l'élément carbonate qui constitue celle-ci, ou sert même à la réparer.
La maladie de l'huître n'est donc qu' une hypersécrétion ; c'est sans
doute beaucoup, et nous continuons à la plaindre, comme nous plaignons
un
