A PIGEON, oppressed by excessive thirst, saw a goblet of water
painted on a signboard. Not supposing it to be only a picture,
she flew towards it with a loud whir and unwittingly dashed
against the signboard, jarring herself terribly. Having broken
her wings by the blow, she fell to the ground, and was caught by
one of the bystanders.

Zeal should not outrun discretion.