Sunday, 25 May 2008

Pliny's misconceit

A beautifully poetic ancient Arab narrative suggests that pearls are created by the oyster sipping the moonlight dew off the surface of the water.

Curiously this literary myth assumed a credibility and plausibility in early texts, which carried on right up into the middle of the second millennia. The Roman savant Pliny in his Historia Naturalis repeated the whimsy as if it were scientific fact. He even suggested the colour of a pearl was down to the weather.

”If the dew is pure and clear, then are the pearls are white, faire and orient…but if grosse and troubled, the pearls likewise are dim, foul and duskish…”

In such awe were his words held that no one it seemed wanted to contradict him for more than 1500 years. Middle Age manuscripts followed this idea unquestioningly, which perhaps is a sign of the cloistered distance between the literate and the water. It was the first Europeans exploiting the oyster beds of the Americas who realised that it was “some old philosopher’s conceit”, as Richard Hawkins put it. Scientifically, Anselmus de Boot was the first to argue in 1600 that the pearl was generated from the nacre inside of the shell. Even this would have to wait a further century before the physicist Reaumnur could prove it satisfactorily with the advent of the microscope.

The misconception is the more strange because pearls were so valued throughout early history. Possibly associations of wealth and religion allowed their mystery to go unquestioned. Certainly the early Chinese already knew that if they placed beads or tiny figurines of deities inside the soft mantle of a live oyster, the oyster would respond and coat it with the same mother-of-pearl that it used to make its own shell. These beads and carvings were then taken to the temples and offered to the gods in the hope that they would bestow good luck upon the donor. Early Chinese texts said the pearl was formed “as if by disease” which is a pretty good clue that they realised pearls came from hard objects being inserted inside the shell. A grain of sand is often quoted, but in reality it is usually something larger and less likely to be dislodged. The theory which had defied learned men until 4000 years was not too dissimilar from the principles that would eventually be adopted in Ayuga Bay, Japan and patented in by Kokichi Mikimoto and Tsauhei Mire in 1906 for the cultivation of artificial pearls.