Oysters open completely when the moon is full; and when the crab sees one it throws a piece of stone or seaweed into it and the oyster cannot close again so that it serves the crab for meat. Such is the fate of him who opens his mouth too much and thereby puts himself at the mercy of the listener.

The five senses are the ministers of the soul.

O time! swift devourer of all created things!

Learning is the only thing the mind never exhausts, never fears, and never regrets.

Many have made a trade of delusions and false miracles, deceiving the stupid multitudes.

Life, when is spent well, is long.

One day the world will look upon research upon animals as it now looks upon research on human beings.