"Would you mind telling me, Doctor," she asked "how you diagnose mental deficiency in a patient who appears perfectly normal?"
"Very Easy," the psychiatrist replied. "You ask him a very basic and simple question which anyone can answer without any problem. If he or she thinks or hesitates, that gives you the first clue."
"What kind of question?" she asked "Could you give an example"
"Well, you might ask , ' Vasco de Gamma made nearly five trips around the world and died during one of them. Which one?"
The lady thought for a moment, and then said with a nervous laugh, "You wouldn't happen to have another example would you? I must confess I don't know very much about history."
