A Libby lesson? LEONARDO DA VINCI, speaking in about the year 1500 said, as rendered into English by Edward MacCurdy 1939: (No, he was not talking to me!) "This (the oyster) opens completely when the moon is full and when the crab sees it it throws a piece of stone or a twig into it and thus prevents it from closing up, so that it serves the crab for a meal. So it may be with the mouth when it tells its secret, that it puts itself at the mercy of the indiscreet listener." Leonardo / TT