Young Mia - only 4 years' old - returned home from Nursery School complaining of a sore tummy.
"'s because your tummy is empty", her mother replied kindly. "You will feel better when you have something in it". Mummy then made Mia a small snack, and ... ... sure enough, Mia felt better after eating it.
Later the same afternoon, Mia's class tutor dropped by to see her mummy. While the two adults were chatting, the tutor mentioned she'd had a bad headache for most of the day.
At which point, Mia perked up and, turning to her tutor, suddenly announced:
"'s because it's empty - you'd feel better if you had something in it!"
... out of the mouths of babes and sucklings.