The Swan Taken for the Goose

A wealthy man kept a goose and a swan together, not for the same purpose, but the one for its song, the other for his table. Now when the goose had to undergo the fate for which it was being reared, it was night, and the darkness did not allow the two birds to be told apart. But the swan, carried off in the goose's place, struck up a song, the prelude of its death. Its voice made it known, and its song saved it from death.