A noted psychiatrist was a guest at a blonde gathering, and his hostess naturally broached the subject in which the doctor was most at ease.
"Would you mind telling me, Doctor," she asked, "how you detect a mental deficiency in somebody who appears completely normal?"
"Nothing is easier," he replied. "You ask a simple question which anyone should answer with no trouble. If he hesitates, that puts you on the track."
"What sort of question?"
"Well, you might ask him: Captain Cook made three trips around the world and died during one of them. Which one?"
The blonde thought a moment, then said with a nervous laugh, "You wouldn't happen to have another example would you I must confess I don't know much about history."