When a rattlesnake got loose in the second-floor hall of the science building at my university, it created quite a furor. Fortunately, one of the professors was an expert on snakes.

An agitated student ran to fetch him, urging him to come quickly, as a dangerous snake was loose and terrorizing everyone in the building.

The professor leisurely strolled out into the hall, examined the snake from head to tail, and calmly returned to his office. “It’s not one of mine,” he said, and closed the door.