The polite policeman explained that this elderly gentleman said that he was lost in the park... and couldn't find his way home.
"Oh Morris ", said grandma, "You've been going to that park for over 30 years! So how could you get lost ?"
Leaning close to grandma, so that the policeman couldn't hear. Morris whispered, "I wasn't lost... I was just too tired to walk home."
It has recently been discovered that research causes cancer in rats.